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STATE STANDARD OF THE USSR UNION

Tested 1985

Failure to comply with the standard is punishable by law

1. The design and dimensions of the flared ends of the pipes must correspond to those indicated in Fig. 1 and in table. 1.

*Size provided by tool

Note. It is allowed to use pipes made of steel grade 12Х18Н10Т with a diameter D H1 , exceeding the upper deviation of the tolerance field d 9, while the diametric tension of the nipple on the pipe should not exceed 0.16 mm.

*Size for reference.

Table 1

Dimensions in mm


	Limit deviations

2 , 3. (Changed edition, Amendment No. 1, 2).

4. When flaring pipes into a nipple radius r control only by the lower deviation.

5. For pipes made of steel grades 20A and 20, subjected to sandblasting, the roughness parameter of the inner surface of the cone of the flared part should be no more Ra 2.5 microns GOST 2789-73.

6. Longitudinal and annular marks, scratches, nicks and cracks are not allowed on the inner surface of the cone of the flared part of the pipe.

7. The depth of prints from the dies (nipples) and longitudinal marks on the outer surface of the cone of the flared part of the pipe should not exceed 0.03 mm, but should not go beyond the tolerance for wall thickness.

The depth of prints from the dies (nipples) on the remaining external surfaces of the pipes should not exceed the tolerance limits for wall thickness.

8. Transition internal conical surface The transition from the flared part of the pipe to the cylindrical one should be smooth, without a transverse annular flow. A sharp transition is allowed without the formation of an annular influx.

For aluminum alloy pipes with D n? 10 mm slight overflow is allowed.

The transition from the inner and outer conical parts to the cylindrical part during calibration should be smooth.

Note: Removal by cutting of the annular bead at the transition of the inner conical surface of the flared part of the pipe to the cylindrical one is not allowed.

9. The edge of the cone of the flared part of the pipe should not have cracks, burrs and should be rounded.

10. The wall thickness at the edge of the conical flared part of the pipe should not be less than 70% of the wall thickness of the cylindrical part of the pipe. For aluminum alloy pipes with D n 8 mm, a wall reduction of up to 55 - 60% is allowed.

Dimensions in mm

	Material grade	Wall thickness, S

		Weight 1 m, kg



	12Х18Н10Т (Х18Н10Т)




	12Х18Н10Т (Х18Н10Т)




	12Х18Н10Т (Х18Н10Т)




	12Х18Н10Т (Х18Н10Т)




	12Х18Н10Т (X18H10T)




	12Х18Н10Т (Х18Н10Т)




	12Х18Н10Т (Х18Н10Т)




	12Х18Н10Т (Х18Н10Т)




	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	I2X18H10T (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12X18H10T (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)

2. Pipes diameters D n = 30 mm and D n = 34 mm may be used in technically justified cases.

(Changed edition, Amendment No. 1, 2).

15. Technical specifications - according to GOST 13977-74.

UDC 62t.643.4:006.354 Group G18

STATE STANDARD OF THE USSR UNION

GOST

PIPING CONNECTIONS

BY OUTER CONE 13977-74 1 2

Specifications

Tube connections on external cone. Specifications

Resolution State Committee standards of the Council of Ministers of the USSR dated September 10, 1974 No. 3124, the implementation period is set

Tested 1985

Failure to comply with the standard is punishable by law

This standard applies to pipeline connections with an outer cone, used in various liquid and gas environments, including aggressive ones, at temperatures from minus 60 to plus 500 ° C and pressures up to 106 MPa (1060 kgf/cm 2), in depending on the materials of pipes and fittings on aircraft and their servicing equipment.

It is allowed to use these compounds in other types of equipment subject to the requirements of this standard.

1. TECHNICAL REQUIREMENTS

1.1. The grades of fittings materials, the combination of pipe and fittings materials and the permissible temperatures for their use must correspond to those indicated in the table. 1. Examples of assembling pipes and fittings are given in Appendix 1.

* Reissue (January 1988) with Amendments L® 1, 2, approved in December 1980, January 1986 (I US 3-81, 5-86).

Type of fittings	Material grades	Permissible temperature in C
Type of fittings	fittings	Permissible temperature in C
Feeders, adapters, elbows, tees, crosses, plugs, plugs, covers	13X11N2V2MF (1Х12Н2ВМФ)
Nipples, union nuts, nuts
Feeders, adapters, elbows, tees, crosses, washers, plugs, covers

Union nuts^ nuts, adapters, adapters, elbows, tees, crosses, plugs, plugs, covers


Nuts, union nuts, adapters, adapters, plugs, plugs, covers
	45, ZOHGSA
Angles, tees, crosses

Nipples, union nuts, nuts
Feeders, adapters, elbows, tees, crosses	Br.AZhMtsYu-3 -1.5

3.2. The material for truo and fittings must comply with the technical documentation specified in table. 2.

GOST 13977-74 S. 11

1.6. Operating and maximum permissible tightening torques union nuts^ connections of pipelines made of steel grades 20A, 12Х18Н10Т and aluminum alloy when testing them for tightness with hydraulic or air pressure must correspond to those indicated in the table. 5.

Table 5

Pipe size £> H XS, mm	Tightening torques, Nm (kgcm), for pipes made of
	steel grades 20 A and 12XI8H10T		aluminum alloy
		Maximum acceptable		Maximum acceptable
		Maximum acceptable		Maximum acceptable

Note. Tightening the union nuts of connections for which torque values are not specified should be done with wrenches in accordance with GOST 2839-80 and GOST 2841-80.

1.2-1.6.

1.7. The union nuts of pipeline connections during assembly on products are tightened with wrenches in accordance with GOST 2839-80 or GOST 2841-80.

The union nuts for critical connections are tightened using torque wrenches.

1.8. The fittings for pipeline connections must be heat treated:

parts made of ZOHGSA grade steel at 29.0^-35.5. NKS E;

nipples and nuts made of steel grade 14Х17Н2 for 23.0-^32.0 HRC S; parts made of steel grade 13Х11Н2В2МФ for 25.0-^35.0 HRC S; parts made of steel grades 12Х18Н9Т and 12Х18Н10Т are hardened; hot-stamped parts made of aluminum alloys are hardened and aged according to T or T1 modes;

stamped parts made of grade 45 steel are normalized; parts made of steel grade 10X11H23T3MP for HRC 3 >32.0; parts made of steel grade 1X16N2AM for 25.0-*-35.0 HRC 3; parts with unspecified heat treatment must have mechanical properties corresponding source material.

(Changed edition, Amendment No. 2).

1.9. The fittings for pipeline connections must have the following protective coatings according to GOST 9.306-85:

Made of stainless steel and bronze - Chem. Pass.;

Carbon and alloy steel: with internal thread- Kdb-9. Chem. ok. Phos. gfj; With external thread- Kd9-12Khim.oks.fos.gfzh and without thread - Kd15.hr.;

Made of aluminum alloys - An.Ox.hr.

To improve the screwability of threaded fittings made of stainless steels The internal surfaces of union nuts may be subjected to copper plating (for operating temperatures up to 300 °C) or electrochemical phosphating with a thickness of 0.003-0.006 mm (for operating temperatures up to 500 °C). In this case, the letters M or Ef are entered into the designation of the nut*, respectively, for example:

Other types of coatings that improve screwability are permitted.

For fittings that come into contact with fuel, cadmium plating must be replaced with galvanizing with the same coating thickness, and the letter C is introduced into the fitting designation, for example:

For parts made of carbon steels operating in oil, it is allowed to use a Chemical coating instead of cadmium plating. Okay. prm, in this case the letter “O” must be entered into the designation of parts, for example:

Coating technology - according to technical documentation approved in accordance with the established procedure.

(Changed edition, Amendment No. 1,2).

1.10. Fittings made from aluminum alloys can be subjected to color anodizing in colors corresponding to the color markings of pipelines.

1.11. Additional protective coatings for fittings must be assigned in accordance with technical documentation approved in the prescribed manner.

1.12. By agreement of the parties, it is allowed: not to cadmium coat (not galvanize) the conical and internal cylindrical sealing surfaces of the connecting fittings that have contact with the working fluid; replacement of cadmium plating (zinc plating) with Khim.oks.fos.gfzh coating for the screw-in part of screw-in fittings; no hydrophobization of parts. In this case, the letters U, V, G are entered into the designation of the reinforcement accordingly.

(Changed edition, Amendment No. 2).

1.13. Cracks, spots, burrs, risks, dents and other mechanical damage are not allowed on the surface of the reinforcement.

1.14. The thread must be clean and free of burrs, broken threads and dents.

1.15. Allowed:

a) traces of threads on the surface of the centering belt and on the unprocessed surfaces of angles, tees and crosses;

b) minor dents and marks from stamps - no more than half of the maximum deviations for the corresponding size of reinforcement;

c) surface defects allowed technical specifications on rods from which parts are made;

d) on the outer cylindrical surfaces of the union nuts there are untreated areas (flat areas);

e) an increase in the diameter of the centering belt of the reinforcement by no more than 0.3 mm after thread formation by knurling.

1.16. Not specified in standards maximum deviations sizes:

a) processed surfaces: diametrical - according to Y12;

L12 other covering and male surfaces - according to Y14;. L14;

b) unprocessed surfaces of stamped reinforcement - according to table. 6;

c) “turnkey”: for parts made by stamping and from round bars - according to h 12, for parts made from hexagonal bars - equal to the maximum deviations of the “turnkey” size of the bar. The surfaces of turnkey bosses in stamped fittings are calibrated;

(Changed edition, Amendment No. 1, 2)

1.17. Unspecified radii from machining - -0.4 mm max. (for the instrument). "

1.18. Unspecified stamping radii - R 2.5 mm.

1.19. Stamping slopes - no more than 5°.

1.20. The permissible displacement along the die parting plane is no more than 0.3 mm.

1.21. Metric thread; tolerance fields - according to GOST 16093-81: for external threads of steel parts - 6e; for external threads of parts made of aluminum alloy and bronze - 6h; for internal threads of parts - 5N6N. Runs (reduced), grooves and chamfers - according to GOSTT0549-80.

Notes:

K. When making threads using the rolling method, lead-in chamfers must be made at an angle of 30 ° instead of 45 °.

2. Maximum deviations of radii and chamfers according to GOST 10549-80: ±0.3 for sizes from 0.5 to 1 ash (iokl.) and ±0.5 mm for sizes from 1 to 3mm (incl.).

Table a -6

Dimensions in mm

	Workpiece material
workpiece size		Aluminium alloy
workpiece size
	Prev. off
A. Linear dimensions(except for curvature radii):


St. 16 to 25

St. 25 to 40

St. 40 to 60

St. 60 to 100
B* Dimensions of radii of curvature:

(Changed edition, Amendment No. 1).

1.23. Allowed:

misalignment of the outer cylindrical surfaces and the hexagon - no more than half the tolerance for the turnkey size;

misalignment of the external processed cylindrical surfaces and internal cylindrical surfaces - no more than half the tolerance for internal diameters;

GOST 1E977-74 S. 15

on the internal surfaces of through and intersecting holes in the reinforcement, ledges from misalignment of axes - no more

in all squares, instead of roundings, r = -^-perform

stepped ledges from the intersection of drill holes;

in technically justified cases, in stamped fittings, obtain a turnkey size machining maintaining the required accuracy and with a surface roughness of at least class 4;

by agreement of the parties, manufacture of reinforcement without holes for locking with wire, while adding the letters BK to the designation of the reinforcement, for example;

blunting of an incomplete thread of the connecting element of the fitting;

To improve the tightness of pipeline connections with D H >16 mm, the conical sealing surfaces of rough and fittings are processed with a surface roughness of class 8 instead of class 7.

(Changed edition, Amendment No. 2).

1.24. Dimensions and maximum deviations for reinforcement must comply with those specified in the standards before coating

1.25. For parts intended for use in oxygen systems, c-symbol The letter K must be added, for example:

1.26. When using pipeline connections established by standards, it should be taken into account that the endurance limit of a pipeline made of steel grade 12Х18Н10Т with dimensions D„ Xs equal to 12x1 mm, determined at normal temperature, is o_1 = 181 MN/m 2 (18.5 kgf/mm 2).

Note. Material. pipes - according to GOST 19277-73.

2. ACCEPTANCE RULES

2.1. To verify compliance of fittings, pipes and their connections with the requirements of this standard, acceptance tests are established.

2.2. Each batch of fittings and pipes is subjected to acceptance tests.

The batch must consist of parts of the same grade of material and the same standard size.

2.3. Acceptance tests are carried out in the following scope and sequence:

a) control of the dimensions of fittings and pipes and checking the fit of conical surfaces - 3% of the batch, but not less than 10 pieces;

b) determination of the wall thickness at the edge of the flared part of the pipe - 2% of the batch, but not less than 10 pieces;

c) checking the skew angle of the flared part of the pipe relative to the axis of the pipeline - 2 pcs. from the party;

d) checking the condition of the inner surface of the pipe - continuous control; .

e) tests for strength and tightness of pipes - continuous control; .

f) external inspection of fittings and pipes - complete control;

g) determination of hardness - 10% of the batch;

h) control of coatings - 1% of the batch, but not less than 3 pieces.

2.4. If, when testing fittings and pipes (clauses 2.3a, b, c, g, h), unsatisfactory results are obtained for at least one of the indicators, the entire batch is returned for revision.

If, when testing fittings and pipes (clauses 2.3 d, e, f), parts are found that do not meet the requirements of this standard, these parts are returned for revision.

Repeated tests according to paragraphs. 2.3a, b, c, h are carried out on a double sample, according to paragraphs. 2.3 g, e, f, g - on every detail.

The results of repeated tests are final.

2.5. The consumer carries out quality control of the received product

duction in the scope and sequence of acceptance tests. .

2.6. The technical control mark must be applied by impact on each suitable part (on the edges of the hexagon or on the turnkey platforms, except for parts whose marking location is indicated on the drawings). It is allowed to mark thin-walled or small-sized parts with paint or on a tag for the entire batch of parts.

3. TEST METHODS

3.1. The dimensions of fittings and pipes are controlled using a universal measuring instrument. Thread inspection should be carried out prior to coating.

(Changed edition, Amendment No. 1).

3.2. Testing the external conical surfaces of the reinforcement for fit is carried out using a special gauge based on the paint imprint on the cone of the reinforcement.

The print must be circular, without a break, and located in a plane perpendicular to the axis of the cone.

3.3. Testing the internal conical surfaces of pipes for fit is carried out using a special gauge using a paint imprint on the gauge cone, while the union nut must be tightened with the operating torque according to table. 5. The print must be circular, without a break. A diagram for testing the inner conical surface of a pipe for fit using a special gauge is shown in the drawing.

It is allowed not to check the paint imprint of the conical surfaces of fittings and pipes when checking connections for tightness using hydraulic or air pressure and tightening the union nut with the operating torque according to Table. 5.

3.4. Control of the wall thickness at the edge of the flared part of the pipe is carried out according to technical documentation approved in the prescribed manner.

3.5. The skew angle of the flared part of the pipe relative to the axis of the pipeline is checked using a universal measuring tool.

3.6. Check internal surfaces pipes for the absence of foreign objects, dents and sagging is carried out by rolling a ball.

3.7. Tests for strength and tightness are carried out according to technical documentation approved in the prescribed manner.

3.8. External inspection of fittings and pipes is carried out visually. The surface of the pipes under the nipple, in the absence of nipple displacement, is checked by cutting two pipes from the batch.

3.9. Hardness control is carried out using hardness measuring instruments using the Rockwell and Vickers methods in accordance with GOST 23677-79.

EVIL. Control of coatings is carried out according to technical documentation approved in accordance with the established procedure.

4. LABELING, PACKAGING, TRANSPORTATION AND STORAGE

4.1. Each part, except for nuts in accordance with GOST 13958-74 and plugs in accordance with GOST 13974-74, must be marked containing:

values of outer diameters of pipes;

P. 18 GOST 13V77-74

symbol of the material grade.

4.5. When transporting parts to countries with tropical climates, packaging and preservation are carried out in accordance with GOST 9.014-78.

4.6. Parts must be transported in clean and dry covered vehicles that protect them from precipitation and mechanical damage.

4.7. Parts must be stored in the packaging provided for by this standard, on racks in light (L) storage conditions in accordance with GOST 9.014-78.

APPENDIX Y

EXAMPLES OF PIPE AND FITTINGS ASSEMBLY

1. Examples of assembling pipes and fittings are shown in Fig. 1-10.

Straight bore pipe assembly

Assembling pipes with a pass-through elbow

table 2

Type of semi-finished product	Material grade
			For products general use	Assortment
	12Х18Н10Т (Х18Н10Т)

		High precision pipes according to GOST 9567-75
		See reference appendix 2

Rods for nipples, union nuts, nuts, passages, adapters, plugs, plugs, caps		See reference appendix 2		Rods normal accuracy according to GOST 2590-71 Rods of the 5th accuracy class according to GOST 8560-7® and GOST 7417 - -75

	14Х17Н2 (1Х17Н2)
	12Х18Н9Т (Х18Н9Т)
	13Х11Н2В2МФ (1Х12Н2ВМФ)			Rods of the 4th accuracy class according to GOST 8560-78 and GOST 7417 - -75

Assembly of pipes with a straight sealable bore


	Hexagonal rods of the 5th and round rods of the 9th accuracy class according to GOST 1628-78
Stampings for angles, tees, crosses		St. reference appendix 2	GOST 105Q-74
	12Х18Н9Т (Х18Н9Т)
	13X11N2V2MF (1Х12Н2ВМФ)

	Br.AZhMtsYu-3-1.5			Round bars, 9th accuracy class according to GOST 1628-78

Continuation of the table. 2

Type of semi-finished product	Material grade	Technical documentation for semi-finished products
		For basic products	For general purpose products	Assortment
Sheets for washers	D1ATV, D16ATV	See reference appendix* 2
	D1AT, D16AT
	12Х18Н10Т (Х18Н10Т)	See reference appendix 2

Notes:

1. Turning rods made of grade 45 steel must be supplied in normalized condition.

2. For products of general use, replacement of materials is allowed:

steel grade 45 steel ZOKHGSA - according to GOST 4543-71;

grade 45 steel (stamping) and grade aluminum alloy. AKv aluminum alloy grade AK4-1 according to GOST 21488--76; aluminum alloy grade D16T aluminum alloy grades AK4-1T1 according to GOST 21488-76 and AK4-1chT1 according to the technical documentation specified in help app 2 (except union nuts);

steel grade 13ХПН2В2МФ steel grade YuХПНИЗТЗМР (Х12Н22ТЗМР) and steel grade 12Х18Н9Т steel grade 12Х18Н10Т according to GOST 5949-75. In case of replacement of materials in symbol fittings must be indicated with the corresponding designation of the brand of the substitute material,

(Changed edition, Amendment No. I, 2).

1.3. Symbols of fittings materials for pipeline connections must correspond to those indicated in table. 3

Table 3

Material group	Designation	Material grade	Symbol of the material grade
Material group	Designation	Material grade	for basic products	for general purpose products
Stainless steel		13Х11Н2В2МФ (1Х12Н2ВМФ)
		14Х17Н2 (Х17Н2, EI268)
		12Х18Н9Т (Х18Н9Т) I2X18H10T (X18H1GT)
		10X11H23T3MP (EPZZ)
		1X16N2AM (EP479)
Alloy and carbon steels
Alloy and carbon steels
Aluminum alloys		D16T, D1ATV, D16ATV, D1AT, D16AT, AK6
Aluminum alloys
		Br. AZhMtsYu-3-1.5

1.4. The working pressures inside the pipeline, depending on the material, diameter and wall thickness of the pipes, are given in Table 4.

1.5. Indicated in the table. 4 working pressures "P slave" are determined at a temperature of plus 20°C; they are for reference and are calculated using the formula

Rrab. =Pjtl>

where P is the minimum destructive pressure in MPa (kgf/cm?) ha - safety factor equal to 3.15.

The minimum breaking pressure is determined by the formula:

where d - inner diameter pipeline; S.- minimum

wall thickness in mm; and c is the tensile strength of pipes in MN/m2.

Outside diameter pipes D	material	Wall thickness, s

Continuation of the table. 4

Dimensions in mm

Pipe outer diameter D	material	Wall thickness, s

		Operating pressure in MPA (kgf/cm*)

continuation of table. 4

Dimensions in mm

Pipe outer diameter D	material	Wall thickness, s

		Working pressure in MPA (kgf/cm2)

Continuation of the table. 4

Dimensions in mm

Pipe outer diameter	Brand of material	Wall thickness, s

		Working pressure in MPa (kgf/cm?)

S. 10 GOST T3977-7D

(Changed edition, Amendment No. 1, 2).

Official publication Reproduction prohibited

Put into effect by Resolution of the State Committee of Standards of the Council of Ministers of the USSR dated September 10, 1974 N 2124

Interstate standard GOST 13977-74

"PIPELINE CONNECTIONS BY EXTERNAL CONE. TECHNICAL CONDITIONS"

Tube connections on external cone. Specifications

Instead of GOST 13977-72

This standard applies to pipeline connections with an outer cone used in various liquid and gas environments, including aggressive ones, at temperatures from minus 60 to plus 500 ° C and pressures up to 106 MPa (1060 kgf/cm 2), depending on materials of pipes and fittings on aircraft and their servicing equipment.

It is allowed to use these compounds in other types of equipment subject to the requirements of this standard.

1. Technical requirements

Table 1

Type of fittings	Material grades		Permissible temperature in °C
Type of fittings	fittings		Permissible temperature in °C
Feeders, adapters, elbows, tees, crosses, plugs, plugs, covers	13Х11Н2В2МФ (1Х12Н2ВМФ)	12Х18Н10Т (Х18Н10Т)
Nipples, union nuts, nuts	14Х17Н2 (1Х17Н2)
Feeders, adapters, elbows, tees, crosses, washers, plugs, covers	12Х18Н9Т (Х18Н9Т)
	12Х18Н10Т (Х18Н10Т)
Union nuts, nuts, adapters, adapters, elbows, tees, crosses, plugs, plugs, covers





Nuts, union nuts, adapters, adapters, plugs, plugs, covers

Angles, tees, crosses




Nipples, union nuts, nuts	14Х17Н2 (1Х17Н2)
Feeders, adapters, elbows, tees, crosses	Br.AZhMts10-3-1, 5

1.2. The material for pipes and fittings must comply with the technical documentation specified in table. 2.

table 2

Type of semi-finished product	Material grade	Technical documentation for semi-finished products
		For basic products	For general purpose products	Assortment
	12Х18Н10Т (Х18Н10Т)	GOST 19277-73	GOST 9941-81

			GOST 8733-74	High precision pipes according to GOST 9567-75
		See Appendix 2		Pipes according to GOST 18475-82
				Soft copper pipes according to GOST 617-90
		See Appendix 2	GOST 1051-73	Standard precision rods according to GOST 2590-88
			GOST 4543-71
	14Х17Н2 (1Х17Н2)		GOST 5949-75	Rods of the 5th accuracy class according to GOST 8560-78 and GOST 7417-75
	12Х18Н9Т (Х18Н9Т)
	13Х11Н2В2МФ (1Х12Н2ВМФ)			Rods of the 4th accuracy class according to GOST 8560-78 and GOST 7417-75
Rods for union nuts, nuts, adapters, plugs, adapters, plugs, caps		21488-97 increased accuracy
	Br.AZhMts 10-3-1, 5	GOST 1628-78		Hexagonal rods of the 5th and round rods of the 9th accuracy class according to GOST 1628-78
		See Appendix 2	GOST 1050-88
	12Х18Н9Т(Х18Н9Т)		GOST 5949-75
	13Х11Н2В2МФ (1Х12Н2ВМФ)

	Br.AZhMts 10-3-1, 5	GOST 1628-78		Round bars, 9th accuracy class according to GOST 1628-78
Sheets for washers	D1ATV, D16ATV	See Appendix 2
	D1AT, D16AT		GOST 21631-76
	12Х18Н10Т (Х18Н10Т)	See Appendix 2		According to GOST 19903-74, 19904-90
			GOST 5582-75, soft

Notes:

1. Turning rods made of grade 45 steel must be supplied in normalized condition.

2. For products of general use, replacement of materials is allowed:

steel grade 45 steel 30KhGSA - according to GOST 4543-71;

steel grade 45 (stampings) and aluminum alloy grade AK6 aluminum alloy grade AK4-1 according to GOST 21488-97; aluminum alloy grade D16T aluminum alloy grades AK4-1T1 according to GOST 21488-76 and AK4-1chT1 according to the technical documentation specified in Appendix 2 (except for union nuts) and steel grade 13Х11Н2В2МФ steel grade 10Х11Н23ТЗМР (Х12Н22ТЗМР) and steel grade 12Х18Н9Т steel grade 12Х18Н10Т on GOST 5949-75. In case of replacement of materials, the symbol of the reinforcement must indicate the corresponding designation of the brand of the replacement material.

1.3. Symbols of fittings materials for pipeline connections must correspond to those indicated in table. 3.

Table 3

Material group	Group designation	Material grade	Symbol of the material grade
Material group	Group designation	Material grade	for basic products	for general purpose products
Stainless		13Х11Н2В2МФ (1Х12Н2ВМФ)
		(X17N2, EI268)
		12Х18Н9Т (Х18Н9Т) 12Х18Н10Т (Х18Н10Т)
		10Х11Н23Т3МР (ЭПЗЗ)
		1X16N2AM (EP479)
Alloy and carbon steels
Alloy and carbon steels
Aluminum alloys		D16T, D1ATV, D16ATV, D1AT, D16AT, AK6
Aluminum alloys
		Br.AZhMts10-3-1, 5

1.4. The working pressures inside the pipeline, depending on the material, diameter and wall thickness of the pipes, are given in Table. 4.

Table 4

Dimensions in mm

Pipe outer diameter D H	Material grade	Wall thickness, s

		Working pressure in MPA (kgf/cm2)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)



	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)


	12Х18Н10Т (Х18Н10Т)

(Changed edition, Amendment No. 1, 2).

1.5. Indicated in the table. 4 operating pressures P slave are determined at a temperature of plus 20°C; they are for reference and are calculated using the formula

R slave = R/p,

where P is the minimum destructive pressure in MPa (kgf/cm2);

n - safety factor equal to 3.15.

The minimum breaking pressure is determined by the formula

where d is the internal diameter of the pipeline;

S- minimum thickness walls in mm.

1.6. The operating and maximum permissible torques for tightening the union nuts of pipeline connections made of steel grades 20A, 12Х18Н10Т and aluminum alloy when testing them for tightness with hydraulic or air pressure must correspond to those indicated in the table. 5.

Table 5

Pipe size D N × S, mm	Tightening torques, N m (kgf cm), for pipes made of
	steel grades 20A and 12Х18Н10Т			aluminum alloy
			Maximum allowed			Maximum allowed
		Prev. off	Maximum allowed		Prev. off	Maximum allowed

Note. Tightening the union nuts of connections for which torque values are not specified should be done with wrenches in accordance with GOST 2839-80 and GOST 2841-80.

1.5, 1.6. (Changed edition, Amendment No. 2).

1.7. The union nuts of pipeline connections during assembly on products are tightened with wrenches in accordance with GOST 2839-80 or GOST 2841-80.

The union nuts for critical connections are tightened using torque wrenches.

1.8. The fittings for pipeline connections must be heat treated:

parts made of steel grade 30HGSA for 29.0-35.5 HRC e;

nipples and nuts made of steel grade 14Х17Н2 for 23.0-32.0 HRC e;

parts made of steel grade 13Х11Н2В2МФ for 25.0-0.35 HRC e;

parts made of steel grades 12Х18Н9Т and 12Х18Н10Т are hardened;

hot-stamped parts made of aluminum alloys are hardened and aged according to T or T1 modes;

stamped parts made of grade 45 steel are normalized;

parts made of steel grade 10Х11Н23Т3МР for HRC e ≥32.0;

parts made of steel grade 1X16N2AM for 25.0-0.35 HRC e;

parts with unspecified heat treatment must have mechanical properties corresponding to the original material.

(Changed edition, Amendment No. 2).

1.9. The fittings for pipeline connections must have the following protective coatings:

Made of stainless steel and bronze - Chem. Pass.;

Made of carbon and alloy steel: with internal thread - Kd6-9. Chem. ok. Phos. gfj; with external thread - Kd9-12. Chem. ok. Phos. gfzh and without thread - Kd15.hr.;

Made of aluminum alloys - An. Oks. hr.

To improve the screwability of threaded fittings made of stainless steel, the internal surfaces of union nuts can be subjected to copper plating (for operating temperatures up to 300°C) or electrochemical phosphating with a thickness of 0.003-0.006 mm (for operating temperatures up to 500°C). In this case, the letters M or Ef are entered into the designation of the nut, respectively, for example:

Union nut 12-13-M GOST 13957-74.

Other types of coatings that improve screwability are permitted.

Cover 12-22-Ts GOST 13976-74

For parts made of carbon steels operating in oil, it is allowed to use a Chemical coating instead of cadmium plating. Oks. prm, in this case the letter O must be entered into the designation of parts, for example:

Cover 12-22-O GOST 13976-74

Coating technology - according to technical documentation approved in accordance with the established procedure.

(Changed edition, Amendment No. 1, 2).

1.10. Fittings made from aluminum alloys can be subjected to color anodizing in colors corresponding to the color markings of pipelines.

1.11. Additional protective coatings for fittings must be assigned in accordance with technical documentation approved in the prescribed manner.

1.12. By agreement of the parties, it is allowed: not to cadmium coat (not galvanize) the conical and internal cylindrical sealing surfaces of the connecting fittings that have contact with the working fluid; replacement of cadmium plating (zinc plating) with Chemical coating. ok. Phos. gfzh for the screw-in part of screw-in fittings; no hydrophobization of parts. In this case, respectively, enter the letters U, V, G into the designation of the reinforcement.

(Changed edition, Amendment No. 2).

1.13. Cracks, spots, burrs, risks, dents and other mechanical damage are not allowed on the surface of the reinforcement.

1.14. The thread must be clean and free of burrs, broken threads and dents.

1.15. Allowed:

a) traces of threads on the surface of the centering belt and on the unprocessed surfaces of angles, tees and crosses;

b) minor dents and marks from stamps - no more than half of the maximum deviations for the corresponding size of reinforcement;

c) surface defects allowed by the technical specifications for the rods from which the parts are made;

d) on the outer cylindrical surfaces of the union nuts there are untreated areas (flat areas);

e) an increase in the diameter of the centering belt of the reinforcement by no more than 0.3 mm after thread formation by knurling.

1.16. Maximum size deviations not specified in the standards:

a) processed surfaces: diametrical - according to H12; h12; other covering and male surfaces - according to H14, h14;

b) unprocessed surfaces of stamped reinforcement - according to table. 6;

c) “turnkey”: for parts made by stamping and from round bars - according to h12; for parts made from hexagonal rods - equal to the maximum deviations of the turnkey size of the rod. The surfaces of the turnkey bosses in stamped fittings are calibrated;

d) corner - according to GOST 8908-81.

(Changed edition, Amendment No. 1, 2).

1.17. Unspecified radii from machining are no more than 0.4 mm (for a tool).

1.18. Unspecified stamping radii - R 2.5 mm.

1.19. Stamping slopes - no more than 5°.

1.20. The permissible displacement along the die parting plane is no more than 0.3 mm.

1.21. Metric thread - according to GOST 9150-81; tolerance fields - according to GOST 16093-81; for external threads of steel parts - 6e; for external threads of parts made of aluminum alloy and bronze - 6h; for internal threads of parts - 5N6N. Runs (reduced), grooves and chamfers - according to GOST 10549-80.

Notes:

1. When making threads using the rolling method, lead-in chamfers must be made at an angle of 30° instead of 45°.

2. Limit deviations of radii and chamfers according to GOST 10549-80 ±0.3 for sizes from 0.5 to 1 mm (excl.) and ±0.5 mm for sizes from 1 to 3 mm (incl.).

Table 6

Dimensions in mm

Workpiece size	Workpiece material
		Aluminum alloy and bronze
	Prev. off
A Linear dimensions (except for radii of curvature)


St. 16 to 25

St. 25 to 40

St. 40 to 60

St. 60 to 100

B. Dimensions of radii of curvatures

1.22. Tapered thread- according to GOST 6111-52.

1.23. Allowed:

The misalignment of the outer cylindrical surfaces and the hexagon is no more than half the tolerance for the turnkey size;

Misalignment of the external machined cylindrical surfaces and internal cylindrical surfaces is no more than half the tolerance for internal diameters;

On the internal surfaces of through and intersecting holes in the reinforcement, the ledges from misalignment of axes are no more than 0.2 mm;

In all squares, instead of roundings, make stepped ledges from the intersection of the drill holes;

In technically justified cases, in stamped reinforcement, obtain a turnkey size by mechanical processing while maintaining the required accuracy and with a surface roughness of at least class 4;

By agreement of the parties, manufacture of reinforcement without holes for locking with wire, while adding the letters BK to the designation of the reinforcement, for example:

Nut M20X 1, 5-31-BK GOST 13958-74

Blunting of an incomplete thread of a connecting element of a fitting;

To improve the tightness of connections of pipelines with D H ≥16 mm, the sealing conical surfaces of pipes and fittings should be processed with a surface roughness of class 8 instead of class 7.

(Changed edition, Amendment No. 2).

1.24. The dimensions and maximum deviations for the reinforcement must comply with those specified in the standards before coating.

1.25. For parts intended for use in oxygen systems, the letter K must be added to the designation, for example

Cover 12-31-K GOST 13976-74

1.26. When using pipeline connections established by standards, it should be taken into account that the endurance limit of a pipeline made of steel grade 12Х18Н10Т with dimensions D H ×s equal to 12x1 mm, determined at normal temperature, is σ -1 = 181 MN/m 2 (18.5 kgf/mm 2) .

Note. Pipe material - according to GOST 19277-73.

2. Acceptance rules

2.1. To verify compliance of fittings, pipes and their connections with the requirements of this standard, acceptance tests are established.

2.2. Each batch of fittings and pipes is subjected to acceptance tests.

The batch must consist of parts of the same grade of material and the same standard size.

2.3. Acceptance tests are carried out in the following scope and sequence:

a) control of the dimensions of fittings and pipes and checking the fit of conical surfaces - 3% of the batch, but not less than 10 pieces;

b) determination of the wall thickness at the edge of the flared part of the pipe - 2% of the batch, but not less than 10 pieces;

c) checking the skew angle of the flared part of the pipe relative to the axis of the pipeline - 2 pcs. from the party;

d) checking the condition of the inner surface of the pipe - continuous control;

e) tests for strength and tightness of pipes - continuous control;

f) external inspection of fittings and pipes - complete control;

g) determination of hardness - 10% of the batch;

h) control of coatings - 1% of the batch, but not less than 3 pieces.

2.4. If, when testing fittings and pipes (clauses 2.3a, b, c, g, h), unsatisfactory results are obtained for at least one of the indicators, the entire batch is returned for revision.

If, when testing fittings and pipes (clauses 2.3 d, e, f), parts are found that do not meet the requirements of this standard, these parts are returned for revision.

Repeated tests according to paragraphs. 2.3a, b, c, h are carried out on a double sample, according to paragraphs. 2.3 g, e, f, g - on every detail.

The results of repeated tests are final.

2.5. The consumer carries out quality control of received products in the scope and sequence of acceptance tests.

3. Test methods

3.1. The dimensions of fittings and pipes are controlled using a universal measuring tool. Thread inspection should be carried out prior to coating.

(Changed edition, Amendment No. 1).

3.2. Testing the external conical surfaces of the reinforcement for fit is carried out using a special gauge based on the paint imprint on the cone of the reinforcement.

The print must be circular, without a break, and located in a plane perpendicular to the axis of the cone.

3.4. Control of the wall thickness at the edge of the flared part of the pipe is carried out according to technical documentation approved in the prescribed manner.

3.5. The skew angle of the flared part of the pipe relative to the axis of the pipeline is checked using a universal measuring tool.

3.6. The internal surfaces of pipes are checked for the absence of foreign objects, dents and sagging by rolling a ball.

3.7. Strength and tightness tests are carried out according to technical documentation approved in the prescribed manner.

3.9. Hardness testing is carried out using hardness measuring instruments using the Rockwell and Vickers methods in accordance with GOST 23677-79.

3.10. Control of coatings is carried out according to technical documentation approved in accordance with the established procedure.

4. Labeling, packaging, transportation and storage

4.1. Each part, except for nuts in accordance with GOST 13958-74 and plugs in accordance with GOST 13974-74, must be marked containing:

values of outer diameters of pipes;

symbol of the material grade.

Nuts in accordance with GOST 13958-74 and plugs in accordance with GOST 13974-74 are marked with a thread designation and a symbol for the material grade.

Marking is carried out by impact on the edges of the hexagon or on turnkey platforms, except for parts whose marking location is indicated on the drawings. For stamped fittings, markings can be applied during the stamping process on the body of the part (except for turnkey platforms) in a raised font. Font - according to GOST 2930-62. Font depth at impact method marking - no more than 0.3 mm. Bronze reinforcement is not marked by material.

For parts subjected to galvanizing and for parts intended for use in oxygen systems, the letters C and K must be added to the marking text, respectively.

For parts made from hexagonal rods, preliminary marking text is allowed on the edge of the hexagon of the rods using a continuous method, and the presence of repeating markings on the edge of the parts is allowed.

It is allowed to mark thin-walled and small-sized parts with paint or on a tag for the entire batch of parts.

4.2. Each part is wrapped in anti-corrosion paper in accordance with GOST 16295-93 and packaged in type I wooden boxes in accordance with GOST 2991-85, lined inside with waterproof paper in accordance with GOST 8828-89. The packaging must ensure the safety of the packaged parts during transportation by any type of transport.

Parts intended for oxygen systems are wrapped in vegetable parchment in accordance with GOST 1341-97. The use of grease and oily wrapping material is not permitted.

Each box contains parts of only one type.

Gross weight no more than 32 kg.

4.3. Each box contains a passport and a packing list, which indicates:

name or trademark of the manufacturer;

symbol of the part;

number of details;

date of manufacture;

4. Parts intended for use in oxygen systems must be degreased before assembly.

5. For locking, it is necessary to use wire with a diameter of 0.8-1.2 mm. The wire must be twisted, be in a taut state and protect threaded connections from self-unscrewing. Breaks and flattening of the wire are not allowed.

The seals must be pressed against some surface, and the ends of the wire must be bent and pressed against the seal. Fastening the wire in assemblies according to Fig. 3-5 and 7, 8, 10 in order to ensure locking of connections, make them to any fixed structural element or behind a special eye or hole.

The brand of wire, the type of seal and the type of suspension of the caps (plugs) are assigned by the product developer. At the discretion of the product developer, other types of locking are allowed, as well as the absence of locking and sealing.

Appendix 2

Technical documentation for semi-finished products for main purpose products

Type of semi-finished product	Material grade	Technical documentation
		OST 1 90038-71
Rods for nipples, union nuts, nuts, adapters, adapters, plugs, plugs, caps		TU 14-1-2330-77
		ChMTU 1-950-74
	14Х17Н2 (1Х17Н2)	TU 14-1-378-72;
	12Х18Н9Т (1Х18Н9Т)	TU 14-1-377-72
	13Х11Н2В2МФ (1Х12Н2ВМФ)	TU 14-1-3297-82; TU 14-1-1791-76
Rods for nuts, adapters, adapters, plugs, plugs, caps		GOST 21488-97; OST 1 90174-75
Stampings for angles, tees, crosses		OST 1 90085-73, group 3
	12Х18Н9Т(Х18Н9Т)	OST 1 90176-75, group 3
	13Х11Н2В2МФ (1Х12Н2ВМФ)	OST 1 90176-75, group 3
		OST 1 90073-72, group 3
Sheets for washers	D1ATV, D16ATV	OST 1 90070-72
Sheets for washers	12Х18Н10Т (Х18Н10Т)	TU 14-1-2186-77

Notes:

1. It is allowed to replace materials: steel grade 45 with steel grade 30KhGSA TU 14-1-950-74 (rods) and OST 1 90085-73 (stampings); steel grade 45 (stampings) and aluminum alloy grade AK6 aluminum alloy grade AK4-1 according to OST 1 90073-72; steel grade 12Х18Н9Т steel grade 12Х18Н10Т; steel grade 13Х11Н2В2МФ steel grade 10Х11Н23Т3МР (Х12Н22ТЗМР) according to TU 14-1-378-72, TU 14-1-312-72; steel grade 13Х11Н2В2МФ steel grade 1Х16Н2АМ (EP479) according to TU 14-1-948-74 and TU 14-1-3575-83. In case of replacement of materials, the symbol of the reinforcement must indicate the corresponding designation of the brand of the replacement material.

2. The assortment is indicated in table. 2 GOST 13977-74.

(Changed edition, Amendment No. 1, 2).

UDC 62t.643.4:006.354 Group G18

STATE STANDARD OF THE USSR UNION

OUTER CONE PIPELINE CONNECTIONS

GOST 13977-74*

Specifications

Tube connections on externa! cone Specifications

GOST 13977-72

By Resolution of the State Committee of Standards of the Council of Ministers of the USSR dated September 10, 1974 No. 2124, the introduction date was established

It is allowed to use these compounds in other types of equipment subject to the requirements of this standard.

Tested 1985

Failure to comply with the standard is punishable by law

1. TECHNICAL REQUIREMENTS

Official publication

Reproduction is prohibited

* Reissue (January 1988) with Amendments No. 1, 2, approved in December 1980, January 1986 (IUS 3-81. 5-86)

Table 1

Type of fittings	Material grades	Acceptable temperature
Type of fittings	fittings	Acceptable temperature
Conductors, adapters, elbows, tees, crosses, plugs, plugs, covers	(1Х12Н2ВМФ)
Nipples, union nuts, nuts
Adapters, adapters, angles, tees, crosses, washers, plugs, caps

Union nuts, nuts, bushings, adapters, elbows, tees, crosses, plugs, plugs, caps


Nuts, union nuts, passages, adapters, plugs, plugs, covers
	45, ZOHGSA
Angles, tees, crosses

Nipples, union nuts, nuts
Feeders, adapters, coals, tees, crosses	Br.AZhMtsYu-3 -1.5

1.2. The material for pipes and fittings must comply with the technical documentation specified in table. 2.

table 2

Type of semi-finished product	Material grade
			For general purpose products	Assortment
	12Х18Н10Т (Х18Н10Т)	GOST 19277-73	GOST 9941-81

			GOST 8733-74	High precision pipes according to GOST 9567-75
		See reference appendix 2		Pipes according to GOST 18475-82
				Soft copper pipes according to GOST 617-72
Rods for nipples, union nuts, nuts, passages, adapters, plugs, plugs, covers		See reference sheet attached 2	GOST 1051-73	Standard precision rods according to GOST 2590-71 Rods of the 5th accuracy class according to GOST 8560-^78 and GOST 7417- -75
			GOST 4543-71
	14Х17Н2 (1Х17Н2)		GOST 5949-75
	12Х18Н9Т (Х18Н9Т)
	13Х11Н2В2МФ (1Х12Н2ВМФ)			Rods of the 4th accuracy class according to GOST 8560-78 and GOST 7417- -75

GOST 13977-74 S.

Type of semi-finished product	Material grade	Technical documentation for semi-finished products
		For basic products	For general purpose products	Assortment
Rods for union nuts, nuts, passages, plugs, adapters, plugs, caps		increased accuracy
	Br.AZhMts 10-3-1.5	GOST 1628-78		Hexagonal rods of the 5th and round rods of the 9th accuracy class according to GOST 1628-78
		St. reference attached not 2	GOST 105Q-74
	12Х18Н9Т (Х18Н9Т)		GOST 5949-75
	13X11N2V2MF (1Х12Н2ВМФ)

	BrAZHMtsYU-3-1.5	GOST 1628-78		Round bars, 9th accuracy class according to GOST 1628-78

4 GOST 13977-74

Notes

1. Turning rods made of grade 45 steel must be supplied in normalized condition.

2. For products of general use, replacement of materials is allowed:

steel grade 45 steel ZOKHGSA - according to GOST 4543-71;

steel grade 45 (stampings) and aluminum alloy grade AK6 aluminum alloy grade AK4-1 according to GOST 21488-76; aluminum alloy grade D16T aluminum alloy grades AK4-1T1 according to GOST 21488-76 and AK4-1chT1 according to the technical documentation specified in reference Appendix 2 (except for union nuts);

steel grade 13Х11Н2В2МФ steel grade 10Х11ШЗТЗМР (Х12Н22ТЗМР) and steel grade 12Х18Н9Т steel grade 12Х18Н10Т according to GOST 5949-75. In case of replacement of materials, the symbol of the reinforcement must indicate the corresponding designation of the brand of the replacement material

(Changed edition, Amendments No. 1,2).

GOST 13977-74 S.

1.3. Symbols of fittings materials for pipeline connections must correspond to those indicated in table. 3

Table 3

Material group	Designation	Material grade	Symbol of the material grade
Material group	Designation	Material grade	for basic products	for general purpose products
Stainless steel		13Х11Н2В2МФ (1Х12Н2ВМФ)
		14Х17Н2 (Х17Н2, EI268)
		12Х18Н9Т (Х18Н9Т) 12Х18Н10Т (X18H1GT)
		10X11H23T3MP (EPZZ)
		1X16N2AM (EP479)
Alloy and carbon steels
Alloy and carbon steels
Aluminum alloys		D16T, D1ATV, D16ATV, D1AT, D16AT, AK6
Aluminum alloys
		Br. AZhMtsYu-3-1.5

1.4. The working pressures inside the pipeline, depending on the material, diameter and wall thickness of the pipes, are given in Table. 4.

1.5. Indicated in the table. 4 operating pressures P slave are determined at a temperature of plus 20°C; they are for reference and are calculated using the formula

Rrab “1G ~ PI

where P is the minimum destructive pressure in MPa (kgf/cm 2) n is the safety margin equal to 3.15.

The minimum breaking pressure is determined by the formula:

where d is the internal diameter of the pipeline; S - minimum wall thickness in mm; o in - tensile strength of pipes in MN/m 2.

Table 4

Dimensions in mm

Pipe outer diameter D	material	Wall thickness, s

		Working pressure in MPA (kgf/cm2)

GOST 13977-74 S. 9

Pipe outer diameter D	material	Wall thickness, s

		Working pressure in MPA (kgf/cm*)

8 GOST 13977-74

Pipe outer diameter D	material	Wall thickness, s

		Working pressure in MCA (kgf/cm2)

GOST 1ЭУ7-74 С

Pipe outer diameter	material	Wall thickness, s

		Working pressure in MPa (kgf/cm*)

and~££Ш IDOJ 01

KB. The operating and maximum permissible tightening torques for union nuts, pipeline connections made of steel grades 20A, 12Х18Н10Т and aluminum alloy when testing them for tightness with hydraulic or air pressure must correspond to those indicated in the table. 5.

Ta b 1 and ca 5

Tightening torques, N*m (kgf-cm), for pipes made of
steel grades 20 A and 12Х18ы0Т		aluminum alloy
	Maximum acceptable		Maximum acceptable
	Maximum acceptable		Maximum acceptable

Note. Tightening the union nuts of connections for which torque values are not specified should be done with wrenches in accordance with GOST 2839-80 and GOST 2841-80

1.2-1.6.

1.7. The union nuts of pipeline connections during assembly on products are tightened with wrenches in accordance with GOST 2839-80 or GOST 2841-80.

The union nuts for critical connections are tightened using torque wrenches.

1.8. The fittings for pipeline connections must be heat treated:

parts made of steel grade ZOKHGSA at 29.0 h-35.5 NNS E;

nipples and nuts made of steel grade 14Х17Н2 for 23.0-^32.0 HRC 9; parts made of steel grade 13Х11Н2В2МФ for 25.0n-35.0 HRC 3; parts made of steel grades 12Х18Н9Т and 12XI8H10T are hardened; hot-stamped parts made of aluminum alloys are hardened and aged according to T or T1 modes;

stamped parts made of grade 45 steel are normalized; parts made of steel grade 10X11H23T3MP for HRC 3 >32.0; parts made of steel grade 1X16N2AM for 25.0^35.0 HRC 3; parts with unspecified heat treatment must have mechanical properties corresponding to the original material. (Changed edition, Amendment No. 2).

1.9. The fittings for pipeline connections must have the following protective coatings in accordance with GOST 9.306-85:

Made of stainless steel and bronze - Chem. Pass.;

Made of carbon and alloy steel: with internal thread - Kdb-9. Chem. ok. Phos. gfj; with external thread - Kd9-12Khim.oks.fos.gfzh and without thread - Kd15.hr.;

Made of aluminum alloys - An.Ox.hr.

To improve the screwability of threaded fittings made of stainless steel, the internal surfaces of union nuts can be subjected to copper plating (for operating temperatures up to 300 °C) or electrochemical phosphating with a thickness of 0.003-0.006 mm (for operating temperatures up to 500 °C). In this case, the letters M or Ef are entered into the designation of the nut, respectively, for example:

Union nut 12-13-M GOST 13957-74.

Other types of coatings that improve screwability are permitted.

Cover 12-22-Ts GOST 13976-74.

Cover 12-22-0 GOST 13976-74.

Coating technology - according to technical documentation approved in accordance with the established procedure.

(Changed edition, Amendment No. 1, 2).

1.10. Fittings made from aluminum alloys can be subjected to color anodizing in colors corresponding to the color markings of pipelines.

1.11. Additional protective coatings for fittings must be assigned in accordance with technical documentation approved in the prescribed manner.

1.12. By agreement of the parties it is allowed; do not cadmium (do not galvanize) the sealing conical and internal cylindrical surfaces of the connecting fittings that have contact with the working fluid; replacement of cadmirvanium (zinc plating) with a Khim.oks.fos.gfzh coating for the screw-in part of screw-in fittings; no hydrophobization of parts. In this case, the letters U, V, G are entered into the designation of the reinforcement accordingly.

(Changed edition, Amendment No. 2).

1.13. Cracks, spots, burrs, risks, dents and other mechanical damage are not allowed on the surface of the reinforcement.

1.14. The thread must be clean and free of burrs, broken threads and dents.

1.15. Allowed:

a) traces of threads on the surface of the centering belt and on the unprocessed surfaces of angles, tees and crosses;

b) minor dents and marks from stamps - no more than half of the maximum deviations for the corresponding size of reinforcement;

c) surface defects allowed by the technical specifications for the rods from which the parts are made;

d) on the outer cylindrical surfaces of the union nuts there are untreated areas (flat areas);

e) an increase in the diameter of the centering belt of the reinforcement by no more than 0.3 mm after thread formation by knurling.

1.16. Maximum size deviations not specified in the standards:

a) processed surfaces: diametrical - #12; /g 12 other male and female surfaces - each #14; h 14;

b) unprocessed surfaces of stamped reinforcement - according to table. 6;

c) “turnkey”: for parts made by stamping and from round bars - #12, for parts made from hexagonal bars - equal to the maximum deviations of the “turnkey” size of the bar. The surfaces of turnkey bosses in stamped fittings are calibrated;

d) corner - according to GOST 8908-81 ±

(Changed edition, Amendment No. 1, 2)

1.17. Unspecified radii from machining -^ -0.4 mm max. (for the instrument).

1.18. Unspecified stamping radii - R 2.5 mm.

1.19. Stamping slopes - no more than 5°.

1.20. The permissible displacement along the die parting plane is no more than 0.3 mm.

Table 6

Dimensions in mm

	Workpiece material
Workpiece size		Aluminum alloy and bronze
	Prev. off
A. Linear dimensions (except for radii of curvature);


St. 16 to 25

St. 25 to 40

St. 40 to 60

St. 60 to 100
B Dimensions of radii of curves:

(Changed edition" Amendment No. 1).

1.22. Conical thread - according to GOST 6111-52.

1.23. Allowed:

misalignment of the outer cylindrical surfaces and the hexagon - no more than half the tolerance for the turnkey size;

misalignment of the external processed cylindrical surfaces and internal cylindrical surfaces - no more than half the tolerance for internal diameters;

on the internal surfaces of through and intersecting holes in the reinforcement, the ledges from misalignment of axes are no more than 0.2 mm;

in all squares instead of rounding g == -^-do

stepped ledges from the intersection of drill holes;

in technically justified cases, in stamped reinforcement, obtain a turnkey size by mechanical processing while maintaining the required accuracy and with a surface roughness of at least class 4;

by agreement of the parties, manufacture of reinforcement without holes for locking with wire, while adding the letters BK to the designation of the reinforcement, for example:

Nut N120X1.5-ZGBK GOST 13958-74;

blunting of an incomplete thread of the connecting element of the fitting;

To improve the tightness of connections of pipelines with D H >16 mm, the sealing conical surfaces of pipes and fittings should be processed with a surface roughness of class 8 instead of class 7.

(Changed edition, Amendment No. 2).

1.24. Dimensions and maximum deviations for reinforcement must comply with those specified in the standards before coating

1.25. For parts intended for use in oxygen systems, the letter K must be added to the designation, for example:

Cover 12-31-K GOST 13976-74

1.26. When using pipeline connections established by standards, it should be taken into account that the endurance limit of a pipeline made of steel grade 12Х18Н10Т with dimensions D H Xs equal to 12x1 mm, determined at normal temperature, is -181 MN/m 2 (18.5 kgf/mm 2) .

When iechanna. Material tr u 5y - according to GOST 19277-73.

(Changed edition, Rev. Ml).