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• Introduction
• 1.2 Inverter arc power supplies
• 1.3 Selection of electrodes and welding mode
• 2.1 Classification of doors
• 2.2 The order of assembly of a metal door
• 3. Labor protection
• Conclusion
• Bibliography
• Introduction
• In this term paper, I will try to explain in detail the procedure for assembling and installing a metal door using manual arc welding.

Connected by welding various metals, their alloys, some ceramic materials, plastics, glasses and dissimilar materials. The main application is found in the welding of metals and their alloys in the construction of new structures, the repair of various products, machines and mechanisms, and the creation of two-layer materials. Metals of any thickness can be welded. The strength of the welded joint in most cases is not inferior to the strength of the whole metal.

Connection during welding is achieved due to the occurrence of atomic-molecular bonds between the elementary particles of the bodies being joined. The rapprochement of atoms is hindered by uneven surfaces in places where it is planned to connect the parts, and the presence of contaminants in the form of oxides on them.

Depending on the methods used to eliminate the causes that prevent the achievement of a strong connection, all existing varieties welding (and there are about 70 of them) can be classified into three main groups - pressure welding (solid state welding), fusion welding (liquid state welding) and fusion and pressure welding (liquid-solid state welding).

In fusion welding, the connection of parts is achieved by local melting of the metal of the elements being welded - the base metal - along the edges at the point of their contact or the base and additional metals and wetting the solid metal with liquid. The molten base or base and additional metals spontaneously (spontaneously) without the application of external force merge, forming a common so-called weld pool. As the heat source is removed, solidification occurs - crystallization of the metal of the weld pool and the formation of a seam connecting the parts into one. The weld metal in all types of fusion welding has a cast structure.

Powerful heat sources are used to melt metal. Depending on the nature of the heat source, electric and chemical fusion welding are distinguished: in electric welding, the initial source of heat is electric current; in chemical welding, an exothermic combustion reaction of gases (gas welding) or a powdered combustible mixture (thermite welding) is used as a heat source.

• Objective:
• To study the features of the assembly and installation of a metal door made of sheet and angle steel St3.
• Tasks: learn how to choose the right sizes, necessary materials, current strength and welding methods for assembling and installing a metal door.
• Relevance. Doors of this type are widely in demand in industrial, warehouse, basements, garages, technical rooms, as well as multi-apartment buildings, as an entrance door to an apartment and an entrance.
• 1. General information about the steel used. choice of arc power source, electrodes and welding mode
• 1.1 General information about the steel used
• Steel is an alloy of iron with carbon and/or other elements. Steel contains no more than 2.14% carbon. In this case, we use steel grade St3, which means carbon structural steel of ordinary quality (see Table 1).
• Table 1

Substitute
Classification	Structural carbon steel of ordinary quality
Application:	load-bearing and non-bearing elements of welded and non-welded structures and parts operating at positive temperatures. Shaped and sheet products up to 10 mm thick for load-bearing elements of welded structures operating under variable loads in the range from -40 to +425 °С. Rolled products from 10 to 25 mm - for load-bearing elements of welded structures operating at temperatures from -40 to +425 ° C, subject to delivery with guaranteed weldability.
Chemical composition in% steel grade 3 (St3sp)

1.2 Inverter arc power supplies

Power Supply Selection welding inverter in such cases, it is carried out from autonomous generators of various types. The wrong choice of an autonomous generator as an external power source for the welding inverter can lead to its rapid failure. When choosing a generator, it is not enough to be limited to one selection of power. There are other characteristics of an external autonomous generator that are not very compatible with the characteristics of the inverter.

Power supply of the welding inverter from an external city or power network does not cause incompatibilities affecting the operation of the welding inverter. All welding units available on the shelves of the store are adapted specifically for power from the mains. The input rectifier unit at the input of the welding converter is designed to operate at a frequency of 50 Hz and a voltage of 220 or 380 volts, i.e. with a conventional or power network.

The mismatch in the operation of the generator and inverter occurs due to the difference in the nature of the load. When the inverter is running, they carry a capacitive component. Generators, in turn, are designed for active-inductive consumers, and as the load current increases, they compensate for the voltage drop. In this case, with an increase in current due to the capacitive component of the load, the inverter has its own increase in voltage, and Feedback at the generator by current, compensating the voltage from the load, causes an even greater increase in voltage in the inverter module. An overvoltage that occurs with an increase can lead to device failure or a decrease in the life of the electronic circuit.

A similar situation does not arise when welding rectifiers and transformers made according to power circuits are connected to an autonomous generator. Their active-inductive load is fully combined with the characteristics of the operation of generators of all types of excitation. For inverters, it is possible to use generators with oversized capacities. With a power reserve of two times, it is possible to avoid an increase in voltage at the generator during inverter operation. The second option is to use special generators designed for an active-capacitive load. It can provide voltage reduction idle move at the generator and increasing the frequency of the current to 52 Hz.

If the power reserve of the generator is insufficient, then it is better to use an external network to connect the welding inverter to work.

In this work, I used the Brima ARC 250 inverter type welding machine designed for manual arc welding and stick electrode surfacing on DC steel products in industrial and domestic conditions. It features stable, reliable and efficient performance, portability and low noise during welding. Features of ARC 250 are high efficiency, low energy consumption, mobility, excellent dynamic properties, arc stability, low open circuit voltage, arc power self-regulation, ability to meet various welding requirements.

Adjusting the arc force (short circuit current) allows you to optimally select the depth of metal penetration, and avoid increased spattering of the metal and (or) sticking of the electrode.

1.3 Selection of electrodes and welding mode

In arc fusion welding, consumable electrodes are used, made of cold-drawn calibrated or hot-rolled wire with a diameter of 0.3-12 mm, or flux-cored wire. Electrode tapes and plates are also used as electrodes. Electrodes are classified according to the material, the purpose for welding certain steels, the thickness of the coating applied to the rod, the types of coating, the nature of the slag formed during melting, technical properties weld metal, etc. A certain composition is applied to all electrodes - a coating.

The general purpose of electrode coatings is to ensure the stability of the welding arc and obtain a weld metal with predetermined properties. The most important properties are ductility, strength, toughness, corrosion resistance. The coating performs many important functions.

Firstly, it is gas protection of the welding zone and molten metal, which is formed during the combustion of gas-forming substances. It protects the molten metal from the effects of oxygen and nitrogen. Such substances are introduced into the coating in the form of wood flour, cellulose, cotton fabric.

Secondly, the deoxidation of the metal of the weld pool with elements that have a greater affinity for oxygen than iron. These elements include manganese, titanium, molybdenum, chromium, silicon, aluminum, graphite. Deoxidizers are included in the coating not in pure form, but in the form of ferroalloys.

Thirdly, slag protection. The slag coating reduces the rate of cooling and solidification of the weld metal, thereby facilitating the release of gaseous and non-metallic inclusions. Slag-forming coating components are titanium and manganese ores, kaolin, marble, quartz sand, dolomite, feldspar, etc.

Fourth, alloying the weld metal to give it special properties (increase in mechanical properties, wear resistance, heat resistance, corrosion resistance). Chromium, nickel, molybdenum, tungsten, manganese, titanium are used as alloying components.

In addition, to increase the productivity of welding, iron powder is introduced into the electrode coatings. Such a powder facilitates the re-ignition of the arc, reduces the cooling rate of the deposited metal, which favorably affects welding at low temperatures. The powder content can reach up to 60% of the coating weight. To fix the coating on the electrode rod, binders are used, such as liquid glass. To give the coating better plastic properties, shaping additives are introduced into it, such as bentonite, kaolin, dextrin, mica, etc.

Depending on the materials being welded, all electrodes are divided into the following groups: L - for welding alloyed structural steels with a temporary tensile strength of more than 600 MPa - five types (E70, E85, E100, E125, E150); U - for welding carbon and low-carbon structural steels; B - for welding high-alloy steels with special properties; T - for welding alloyed heat-resistant steels - 9 types; H - for surfacing surface layers with special properties - 44 types. The guaranteed tensile strength of the weld metal is indicated in the brand of electrodes by numbers. For example, the name of the electrode, designated E42, indicates that it is intended for arc welding; the minimum tensile strength of the weld metal is 42 kgf / mm 2.

The choice of electrode diameter for welding is carried out depending on the thickness of the metal to be welded, its grade and chemical composition, edge shapes, welding positions, joint types. The main features of various electrode diameters include:

1. Welding electrodes 1 mm - designed to work with metal, the thickness of which is 1-1.5 mm, with a current strength of 20-25A;

2. Welding electrodes 1.6 mm - in accordance with GOST9466-75 for low-carbon and alloy steel, two sizes are produced 200 or 250 mm, used to work with metals whose thickness is from 1 to 2 mm with a current strength of 25-50A;

3. Welding electrodes 2 mm - according to GOST9466-75 for low-carbon and alloy steel, they are made 250 mm long, 300 mm long is also allowed, the thickness of the metals being welded is from 1 to 2 mm, the current strength is 50-70A;

4. Welding electrodes 2.5 mm - according to GOST 9466-75 for low-carbon and alloyed steel, they are produced with a length of 250-300 mm, a length of 350 mm is also allowed, the thickness of the metals being welded is from 1 to 3 mm, the current strength is 70-100A;

5. Welding electrodes 3 mm - the most widely used electrode diameter, in accordance with GOST9466-75 for low-carbon and alloy steel, three sizes are produced 300, 350 and 450 mm, designed to work with metals, the thickness of which is from 2 to 5 mm with current 70-140A;

6. Welding electrodes 4 mm - a widely used diameter suitable for work on both professional and household equipment. Produced according to GOST9466-75 in two sizes 350 and 450 mm for all types of steel, for metals, the thickness of which is from 2 to 10 mm with a current strength of 100-220A;

7. Welding electrodes 5 mm - electrodes of this diameter require sufficiently powerful welding equipment. In accordance with GOST 9466-75, they are made with a length of 450 mm for low-carbon and alloy steel, and for high-alloy steel, a length of 350 mm is also allowed. Designed to work with metals, the thickness of which is from 4 to 15 mm with a current strength of 150-280A;

8. Welding electrodes 6 mm - designed to work on professional equipment. According to GOST9466-75, it is produced in a length of 450 mm for low-carbon and alloy steel, and for high-alloy steel, a length of 350 mm is also allowed. Designed to work with metals, the thickness of which is from 4 to 15 mm with a current strength of 230-370A;

9. Welding electrodes 8-12 mm - for work on high-performance industrial equipment. In accordance with GOST9466-75, it is produced in a length of 450 mm for low-carbon and alloy steel, and for high-alloy steel, a length of 350 mm is also allowed. Designed to work with metals, the thickness of which is over 8 mm with a current strength of 450A;

At the same time, it should be noted that for a certain electrode diameter, the current strength range for each brand of electrodes is different. For example, with an electrode diameter of 3 mm for UONI 13/55, the current strength is 70-100A, and for MP-3, the current strength is 80-140A.

If manual arc welding is carried out, then it is performed in 2-3 layers, since multi-layer welding provides deep penetration of the root and increases the density of the welded joint. This method is used with and without rotation of the welded joints. In order not to burn through the metal, it is recommended to weld the first layer with electrodes with a diameter of 4 mm at a welding current of 120-140 A. The layers should be welded in one direction with a gradual rotation of the welded section. If a fixed joint is welded, then welding is carried out when the sections are connected into one lash and final assembly pipeline. The procedure for applying welds is as follows: the first layers are welded from the bottom up; subsequent seams - from top to bottom. Locks, or closing sections in adjacent layers of the seam, should be separated from each other at a distance of approximately 60-100 mm; in the ceiling part of the seam, it is convenient to finish welding at a distance of 50-70 mm from the bottom point of the pipe. If it is impossible to perform welding of fixed joints, then a combined method is used. With this method, a joint is welded with an insert, while the lower part of the joint is welded from the inside; the upper part of the seam is welded from the outside. The type of electrodes used is the same as for welding rotary joints. If pipelines are being laid, then manual welding lead only when applying the first layer of the seam.

The welding mode is called the main indicators that determine the welding process, which are established on the basis of the initial data and must be performed to obtain a welded joint of the required quality, size and shape established by the project. These indicators for manual arc welding include: the brand of the electrode, its diameter, strength and type welding current, polarity at direct current, number of layers in the seam. With a multilayer seam - the diameter of the electrode and the current strength for the first and subsequent layers, as well as other characteristics. To determine the welding mode, the initial data are used, for example, the grade and thickness of the base metal, the length and shape of the welds, the design requirements for the quality of the welds (electrode type), and the position of the welds in space.

Depending on the brand of the metal to be welded and its thickness, the type and brand of electrodes are selected. The electrode diameter is selected depending on the position of welding and the thickness of the metal. In the lower welding position, the electrode diameter can be determined by the ratio between the electrode diameter and the thickness of the metal to be welded.

The cross-sectional area of ​​multilayer welds is usually given in the Uniform Norms and Prices for Welding, from which you can easily determine the number of layers (passes) of a multilayer weld.

welding mode. In this work, we use the UONI 13/55 electrode brand, the electrode diameter is 3 mm. The position of the seam in space is vertical, lower and ceiling. Current strength 75 - 100 A (depending on the position of the seam in space)

When welding in a vertical position, the current strength decreases by 10--20%, when welding horizontal seams - by 15--20% and when welding ceiling seams - by 20--25%. When welding in the lower position, the current strength will be exactly 100A, in the vertical position 80 - 100A, and in the ceiling position, the current strength will be even 75 -80A.

The speed of welding (moving the arc) largely depends on the qualifications of the welder and his ability to conduct the welding process with interruptions only to change the electrode. In addition, the welding speed is affected by the deposition rate of the electrodes used and the strength of the welding current. The greater the deposition rate and current strength, the faster the arc moves and, consequently, the welding speed increases. It should be borne in mind that an arbitrary increase in the current strength can cause the electrode to overheat.

steel electrode welding door

2. Classification of doors. production technology of the entrance metal door

2.1 Classification of doors

I. According to the materials:

wooden,

aluminum,

steel,

plastic,

Combined.

II. By way of opening

1. Swing

Can open one way or both. Swing doors can be both internal and external doors.

2. Sliding

Sliding doors widely used for wardrobes. Sliding doors go into a cavity inside the wall or move parallel to it.

3. Swinging

They swing open in both directions, like in the subway, they are very fond of pets. But they are almost never found on sale, only in specialized stores.

III. By appointment distinguish:

1. Doors for residential buildings

2. Doors for public buildings

3. Special doors (shockproof, bulletproof, anti-burglary)

Door designs are different and depend on their requirements. Both in Russia and abroad, they produce doors that open into the room.

2.2 The order of assembly of a metal door

1. First of all, we weld the door threshold onto the tack.

2. Marking and cutting of sheet steel.

2.1. We will need 2 canvases for a large and small door. We apply marking lines on sheet steel using a metric tape measure and chalk. (Fig. 1. a, b).

2.2. Using an angle grinder, we cut out the 1st sheet of sheet steel 3 mm thick, 900mm wide and 1980mm long and the 2nd sheet 1980mm long and 490mm wide (Fig. 2.).

a b

Fig.1.

Fig.2.

2.3. Marking and cutting of angle steel. They will serve as the stiffeners of the product. We cut out the corner steel, which will be located vertically, for the 1st large and for the 2nd door leaf with one length of 1980mm. Next, the mode is horizontal corners, short for a small door 485mm long and 870mm long: (Fig. 3.).

Fig.3.

3 Assembling the door on tacks with electrodes Ш 3mm, grade UONI-13/45

1.1. We weld the stops to the threshold, at a distance of 10 mm from the butt (Fig. 4. a, b)

a b

Fig.4.

We grab the stiffeners. First, we grab the longitudinal ribs (Fig. 5. a.), then the transverse ones (Fig. 5. b, c.) The distance from the channel wall should not exceed (5 mm). Tacks should be 35-50 mm long, at a distance of 150-200 mm. We do the same with the 2nd, small door leaf.

a B C

Fig.5.

1.2. We weld the embedded plates on which the hinges will be welded. Their length should slightly exceed the length of the hinge cup. In order for everything to be exactly on the channel, we weld 2 plates, one on top of the other, they should recede from the door leaf by about 5-6 mm, and we weld 1 plate on the door leaf, the distance from the edge is 2-3 mm. We process the plates: (Fig. 5.).

a b

Fig.6.

1.3. We weld the hinges to the finished embedded plates: (Fig. 7.).

Fig.7.

1.4. Insert a lock. We cut the keyhole (Fig. 8, a). In order to fix it, we use angle steel (Fig. 8, b) and fasten the lock with self-cutting screws: (Fig. 8, c).

a B C

Fig.8.

1.5. We clean the seams from slag and spatter. Perform visual inspection of welds. If defects are found, cut out the necessary section of the weld and weld it again.

Defects and their elimination. Defects in welded joints should be eliminated in the following ways: detected weld breaks and craters are welded; seams with other defects exceeding the allowable ones are removed to the length of the defective area plus 15 mm on each side and welded again; undercuts of the base metal, exceeding the allowable ones, are cleaned and welded, followed by cleaning, which ensures a smooth transition from the deposited metal to the base one.

Residual deformations of structures that have arisen after welding and exceed the values ​​must be corrected. The correction must be made by means of thermal, mechanical or thermomechanical action.

ITK on the topic: "Technological process of manufacturing an entrance metal door"

table 2

	Technological map of welding works
	Name	Quantity
	Equipment: rectifier	VDM 1001, RB-302
	Tool:	- Metal ruler; - Square; - angle grinder - Metal brush; - Outer central; - Slag separator; Electrode holder.
	Materials:	Electrodes brand UONI-13/45
			Total wall thickness	Current strength, A	Electrode diameter in mm	Seam length, mm	Number of points	Qualification category
	Installing the door threshold.
	Mark and cut out 2 door panels and stiffeners along required dimensions doors.
	We assemble the structure. Install stops. We weld the door leaf on tacks and fix it. To do this, we install a support under the canvas on which the canvas will stand.
	Attach the stiffeners to the door leaf. Electrode Sh 3 mm UONI-13/45. The length of the tacks is 35-50 mm.
	We weld the embedded plates on which the hinges will be welded. Processing plates.
	We weld the hinges to the finished overhead plates.
	Let's start installing the lock. Keyhole mode. In order to fix it, we use angle steel and fasten the lock with self-tapping screws.
	Cleaning seams from slag and spatter
		Order of execution
	Perform a visual inspection of the welds.	1. Identification of external defects; 2. Removal of defective areas; 3. Correction of defects.

3. Labor protection

During arc welding and cutting, the welder is exposed to factors such as harmful gases, fumes and exposure to the welding arc. There is also a risk of electric shock. In addition, volatile compounds in the form of dust are generated during operation. It contains substances harmful to human health, such as oxides of manganese, silicon, iron, chromium, and fluorine. The most harmful are chromium and manganese. During welding, the air is polluted with oxides of nitrogen, carbon, hydrogen fluoride. Inhalation of such polluted air is fraught with various violations well-being. They are expressed by headaches, dizziness, nausea, vomiting and general weakness. In addition, toxic substances can be deposited in the tissues of the human body and cause various diseases. Working with covered electrodes causes the most air pollution; less harmful emissions from automatic welding. The effect of all these harmful factors can be significantly weakened or neutralized if security measures are applied in each specific case.

To create favorable working conditions that meet physiological needs human body, sanitary norms establish optimal and permissible meteorological conditions in working area premises.

Rationing of the microclimate in the working premises is carried out in accordance with sanitary regulations and the norms set forth in SanPiN 2.2.4.548-96. Hygienic requirements for the microclimate of industrial premises.

Industrial premises - enclosed spaces in specially designed buildings and structures in which people work constantly or periodically.

A workplace where the microclimate is normalized is a section of the premises (or the entire premises) where labor activities are carried out during the work shift or part of it.

The working area is limited to a height of 2 meters above the floor or platform where the workplaces are located.

The calculation of sanitary and hygienic premises is carried out according to SNiP 2.09.04-87. For the calculation of amenity premises, information about the group is required production processes according to sanitary specifications.

Workplace organization. Depending on the nature of the work, welding can be carried out while in one place or periodically moving around the work site. That's why workplace welder can be both mobile and permanent. Regardless of this, there is a strictly defined set of necessary devices and tools. Among them are: power supply, welding transformer, welding wires, electrode holder, face shield, tarpaulin protective clothing, protective shields, fire extinguishing equipment, necessary tools, asbestos sheet. If welding work is carried out in the cabin, then it is better to paint the walls of the cabin in light gray.

This type of coloring promotes better absorption. ultraviolet rays. In addition, the cabin must have good lighting and ventilation. Floors according to fire safety requirements must be made of brick, concrete or cement. Cabin dimensions - 2 x 2.5 m. Its walls are made of thin metal, plywood, tarpaulin. Both plywood and tarpaulin are impregnated with a fire retardant compound. The welder's desktop should not exceed a height of 0.6-0.7 m. The tabletop material is thick sheet steel. Fiber masks and shields protect the eyes and face of the welder from harmful radiation. The inner side of the body of the shields and masks should have a matte smooth black surface. Radiation protection is also provided by dark green filters (type C).

If welding work is carried out with coated electrodes, then it is better to choose the following filters: at a current of 100 A - light filter C 5, 200 A - C 6, 300 A - C 7, 400 A - C 8, 500-600 A - C 9. If welding is carried out in carbon dioxide at a current of 50-100 A, then a light filter is used C 1, 100-150 A - C 2, 150-250 A - C 3, 250-300 A - C 4, 300 -400 A - C 5. Electric holders are needed to fix the electrode and supply current to it in manual arc welding. There are electric holders of passage, screw, spring, lever and other types. Electroholders allow fixing the electrode in one of three positions: at an angle of 0, 45, 90° relative to the longitudinal axis of the handle.

Conclusion

In this work, we have studied one of the ways technical process assembly and welding of a metal door.

We got acquainted with the features of welding, with defects and their elimination. We learned what the procedure for assembling a metal door should be, learned how to weld and how to choose the right electrodes and welding mode to improve efficiency.

Bibliography

1. Adaskin A.M., Materials science (metalworking): textbook. Allowance for the beginning. prof. Education / A.M. Adaskin, V.M. Zuev. - 5th ed., revised. and additional - M.: Publishing Center "Academy", 2011. - 288 p.

2. Andreev V.V. Inverter power sources for the welding arc // Welder, 2012. No. 6. pp. 25-29.

3. Smirnov VV: Equipment for arc welding. 2011

4. Chuloshnikov P.L. Tutorial for prof. learning. - M.: Mashinostroenie, 2011.

5. Peshkovsky O.I. Manufacturing technology metal structures: Proc. for technical schools.-- 3rd ed., revised. and add.-- M.: Stroyizdat, 2012.-- 350s.

6. Kulikov O.N. Occupational safety in the production of welding works. - M.: Academy, 2013.

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In this article:

For a house to be truly a fortress, the entrance to it must be blocked by reliable metal doors– protection from uninvited guests, cold winds and street noise. Entrance doors made of durable steel are a standard requirement that every inhabitant makes today for his own home.

Although market competition entrance doors high enough, here you can still find a niche: in recent times the demand has increased not only for the quality and reliability of door panels, but also for effective appearance(especially in elite new buildings, well-guarded entrances and cottage settlements). Therefore, having thought over an interesting stylish design and a range of several models, you can enter the average price niche on a par with branded manufacturers.

However, as practice shows, the decisive factor when buying from 80% of consumers is the price. Therefore, even "garage production" - with the help of hand tool and machine tools is quite capable of making a profit in the shortest possible time, which will allow you to step into the next stage of business development.

• GOST 31173-2003 - Steel door blocks. Specifications;
• GOST 23118-99 Steel building structures;
• GOST 5089-97 - Locks and latches for doors. Specifications.

Steel door production equipment

1. Automatic lines

Apply on large factories with high productivity from 200 doors/day and more. The technological process is fully automated, it takes about 2 minutes to make one door leaf. High-precision technology ensures the same geometry of the product, forming profiles, drilling holes for fittings and connecting fasteners, painting the door leaf and filling internal voids - everything happens automatically, with minimal manual intervention.

The welding of the product is also automated, thanks to the use of special welding robots. Strong weld seam connections do not require additional manual cleaning and grinding.

Pros: automated lines allow the production of 500-600 finished products per day with minimal risk of marriage.

Minuses: high price and maintenance costs (lines are made to order, the cost starts from 6 million rubles). For the full operation of such equipment, a large production area (from 1500 m 2) is required, where, in addition to the workshop itself, it is necessary to provide significant areas for storing raw materials and finished products.

2. Semi-automatic lines (using manual labor)

A set of equipment and machines for opening a partially automated production:

• Semi-automatic guillotine or metal cutting machine (plasma - Fig. 4, laser) - from 120,000 rubles;
• Press brake - 70,000 rubles;
• Welding machines (include spot welding, door leafs, welding with tongs, final welding in a carbon dioxide environment) - from 100,000 rubles. Can be replaced by conventional welding machines;
• Painting equipment (paint gun, compressor).

Rice. 4 (Plasma)

With this equipment, you can produce 15-20 doors per day. The required area of ​​the premises is not less than 250 m 2 .

Pros: the cost is quite lifting for medium-sized businesses - the price of a semi-automatic line completely depends on the configuration (from 400,000 rubles). But some machines can be replaced with simpler equipment, which will significantly reduce the start-up capital, but increase the amount of manual labor and, accordingly, the cost of wages to workers.

Minuses: "human factor" - the less automation, the higher the number of defects. In addition, highly skilled craftsmen, trained to work both on machines and manually, will be required to ensure the correct implementation of the production technology at all its stages.

3. Manual labor and machine tools

Minimum set of equipment:

• Bulgarian;
• mechanical guillotine for cutting metal (Fig. 5);
• milling machine;
• lathe;
• auxiliary hand tool.

Pros: minimum costs for the purchase of equipment (from 60,000 rubles) and rental of premises (60-80 m 2).

Minuses: 2-3 doors a day is the maximum productivity for such equipment. Such a mini-production can only be focused on the low price segment. To avoid a large number marriage, we need specialists who can work on metal.

Workshop for the manufacture of metal doors

All the main processes of steel door manufacturing technology must be carried out in separate rooms. Therefore, the production area should provide:

• shop for acceptance and preparation of metal;
• workshop for processing steel sheets and rolled profiles;
• assembly and welding shop;
• paint shop;
• decorative and finishing (and if the finish is made directly at the enterprise, and not purchased from ready-made- then a separate room for the technological line for its production) (Fig. 7);
• assembly and control shop;
• finished products warehouse.

Of the special requirements - the presence of a fire safety system, non-combustible materials for walls and floors, good ventilation.

Technological process of production of metal doors

The manufacturing technology of a steel door includes a certain sequence of actions prescribed in a special document (technological or route map), indicating:

• requirements for the quality of materials;
• rules for their transportation, storage and acceptance;
• a sequential process of converting raw materials into a steel door block, painting and assembling it;
• complex technical requirements for each process
• quality control and verification methods;
• method of transportation, storage of finished products and other specifications(TU of production), which are compiled in accordance with the requirements of GOST 31173-2003.

Main steps technological process production of steel doors

1. Metal preparation

Before going to production, the metal is sorted. The marking, the presence of deformations after rolling or transportation is checked, corrosion and scale are removed. In the warehouse of raw materials and materials, rolled metal is stored stacked or on stable racks (at least 2.5 m high).

2. Marking and cutting blanks

The production of doors begins with cutting sheet metal according to the templates applied with the help of center punches and tracers. For cutting rolled metal use:

• mechanical equipment (guillotine shears, presses, saws);
• oxygen method (cutting on stationary machines with gas cutting or hand cutters);
• laser, plasma cutting.

3. Processing of workpieces

The profile for the door frame is made on bending equipment, where, under the pressure of a press, a metal plate is bent at the required angle.

It can be either a standard rectangular design or an arched model. In the second case, the arcuate profile of the upper part of the door is passed through a rolling machine to give the desired shape. After rolling, the profile is cut into the desired parts.

The blanks are sawn off - to eliminate irregularities and the burr is removed upper layer metal at the cutting points. Sawdust is performed manually, with the help of files or on special sawdust machines. After processing, the blanks are sent to a stamping machine, where holes are punched. different diameter for locks and fittings in accordance with the prepared maps.

4. Assembly and welding

The assembly of the door leaf is carried out using contact welding, which eliminates the deformation of the sheets and ensures the absence of welding seams. The sheets are welded to the frame, a 15-20 mm indent is left on the front side, which will serve as a vestibule. In the manufacture of metal doors, a multi-seam type of welding is used. The density of the fabric structure is achieved by installing special stiffeners.

Door locks are installed simultaneously with stiffeners, in places reinforced with metal plates (the so-called "technological pockets"). A non-combustible basalt slab is used between the door leafs as a seal and sound insulator (alternative options: wood, mineral wool, glass wool, polyurethane foam, polypropylene).

To assembled door hinges are manually welded, observing the necessary gaps between the canvas and door frame. The assembly is carried out according to several types (by marking, in conductors, by copiers) and is controlled at each stage for compliance with the geometry in order to correct the defect if necessary.

5. Treatment with paints and varnishes

After assembly, the door blank is sent for painting. The paint is applied to a cleaned, sanded and degreased surface using one of the following methods:

• jet douche;
• pneumatic spraying (Fig. 13);
• spraying in an electrostatic field.

Nitro, powder, graphite, hammer paint of various colors is used - this coating forms a good protection that protects the door from corrosion and light mechanical damage. After drying, the thickness of the applied layer is controlled and there are no visual defects - air bubbles, unpainted areas, cracks, streaks.

6. Sheathing with decorative elements

To give high wear resistance and original decorative effect, an additional protective coating can be applied to the surface of the workpiece - molded or laminated finishing panels, which are manufactured at the enterprise by cutting (automatic or semi-automatic) according to ready-made templates or purchased in the form of blanks.

Types of skins:

• leather, leatherette, vinyl leather;
• wooden lining;
• chipboard;
• natural wood;
• thermal film plain or with imitation of wood of various species;
• forging elements;
• veneer.

7. Installation of locks, fittings, quality control of the finished product

Inserting fittings and checking locks is done manually. To avoid the characteristic knock of metal on metal when the door is closed, to enhance heat and sound insulation, a special shock-absorbing material is glued onto the door leaf - a rubber seal made of rubber or silicone.

To control the quality of the assembly and the tightness of the door leaf to the frame, the finished product is installed on a control stand. If all requirements are met, the door is packed and sent to the finished product warehouse.

Raw materials for making steel doors

There are two technologies for manufacturing steel doors:

• pipe-coal, using rolled pipes fastened by electric arc welding;
• profile bending - using bent rolled profiles.

Today, the second technology is most successfully used in production, where the raw materials for the manufacture of doors are finished sheets rolled metal products. Many believe that the thicker steel sheet in a metal door, the better. And this is not entirely true. Too heavy doors can lead to a lot of problems, for example, difficulty in opening / closing due to heavy weight, rapid wear of the hinges due to the high load. Therefore, 2 mm is the upper "bar" for standard apartment doors. Each additional millimeter adds about 8 kg of weight.

Required accessories:

• locks;
• loops;
• latches/latches;
• pens;
• additional (closers, eyes, clamps, blocking devices).

Business plan for the production of metal doors

1. It is planned to open a mini-factory for the production of steel entrance doors. Target group consumers - construction organizations and private households.

2. For the legal registration of business, an LLC was created on common system taxation, indicating the following types of OKVED:

• 28.75.21 "Manufacture of armored or reinforced safes, fireproof cabinets and doors";
• 45.25.4 "Installation of metal building structures".

For the production of metal doors and the provision of services for their installation, it is necessary to issue a license in accordance with SNiP 11-23-81. The cost of processing packages of documents and obtaining a license is about 35,000 rubles.

3. The production workshop is planned to be located on 100 m 2 of non-residential leased premises. Rental price - 15,000 rubles / month.

4. Costs for the purchase of equipment - 125,000 rubles:

• guillotine crank shears NK3418A;
• sheet bending mechanism MGL-2500;
• drilling machine 2116K;
• abrasive cutting machine;
• welding machine TDM-403;
• spray gun;
• Bulgarian;
• additional equipment (hand tools, racks, exhibition stand).

5. Calculation of the cost of 1 product - a metal door with a size of 2180 * 1040 mm.

• sheet steel 2mm - 0.098 t * 31,600 rubles = 3096.80 rubles;
• insulation (mineral wool) - 0.2 m 3 * 1475 rubles = 295 rubles.
• electrodes - 4 kg * 43 rubles = 172 rubles;
• mortise lock - 820 rubles;
• loops, handle, peephole - 550 rubles;
• cutting wheels, grinding wheels - 420 rubles;
• primer - 4 l * 87 rubles = 348 rubles;
• solvent - 2l * 210 rubles = 420 rubles;
• paint - 2 kg * 460 rubles = 960 rubles.

Total: 7081.80 rubles

6. Income from sales

It is planned to manufacture and install 3 doors per day with a 21-day working day. The selling price of the product is determined by the method of carrying out comparative analysis market prices and is equal to 12,500 rubles. Installation cost - 1200 rubles.

Projected revenue per month: 63 pieces * 13,700 rubles = 863,100 rubles / month.

Material costs - 63 pieces * 7081.8 rubles = 446 153.4 rubles / month.

7. Other costs of doing business:

• rent - 15,000 rubles;
• electricity - 1200 rubles;
• depreciation of fixed assets - 5750 rubles;
• advertising - 15,000 rubles;
• staff salary (director, 5 workers and a sales manager) - 65,000 rubles;
• payroll taxes -24,375 rubles;
• income tax - 58,124.32 rubles.

Total: 184,449.32 rubles / month.

8. Financial results

Net profit: 863,100 rubles - 446,153.4 rubles - 184,449.32 rubles = 232,497.28 rubles / month.

The initial investment (equipment + license + material costs for 1 month of work + other costs) will pay off in 4 months of work.

A high-quality door serves to protect your home from intruders, and therefore must have high burglary resistance. Developers of door systems are constantly improving production technology, using a combination of new structural elements and materials to meet this requirement.

Door materials

The steel structure consists of many elements made of metal with different characteristics. The choice of metal for certain elements is carried out based on the design features of the system.

Door leaf

Door leaf modern steel structures manufactured using frame technology.

Frame material

The frame is formed from profiled rolled products by welding. Used to create a frame different kinds profiles from the most unreliable stamped thin-walled angle to modern hot-rolled square pipes.

Door trim materials

Finishing materials today are very widely represented. They differ as performance characteristics, as well as for the price. Most available materials for finishing doors - these are MDF panels with lamination, veneering, anti-vandal plastic; vinyl leather and powder coating. Viniliskin leather, as a material for upholstery of doors with internal and outside, is used mainly in the simplest budget designs.

Elite metal doors are decorated with an array of precious woods or a combination of solid wood with elements artistic forging, stained glass and glass inserts.

Door frames

Platbands are selected based on the main decor door structure. Often these elements are mounted on a specially designed metal base welded to door frame. This combination provides not only aesthetics, but also safety. Steel platbands perform protective functions, blocking intruders' access to mounting anchor ties.

To provide the house with a real fortress, it is necessary to block the entrance to it with reliable metal doors that will protect against uninvited guests, noise from the street and cold winds. Entrance metal doors are a standard requirement for every inhabitant of his own home today. What equipment for the production of steel doors is used in their manufacture, the article will tell.

In the manufacture of metal doors, first of all, the technology of their production is determined. This sets the speed of the process, the design features of the product, the accuracy of fitting parts and the quality of the design.

Doors can be produced in three ways:

Method for manufacturing a metal door	Process Features
	This method uses manual labor with minimal equipment. Approach disadvantages: Duration of door production; Large labor costs; Controversial qualifications of workers; Lack of high-tech equipment; Possible deviations of the dimensions of the construction details from the drawings. The main advantage of the method is the possibility of manufacturing doors according to complex special projects.
	Products are manufactured in a fully automated way using robotics. This allows you to minimize costs in the production of metal doors, and provides maximum quality finished product. On the automated line, you can get up to 600 finished doors per day. Process Disadvantages: High price of equipment; The high cost of its maintenance; The need for large areas for the installation of all units, machines, as well as storage of finished products.
	When combining manual and automatic labor, the use of semi-automatic lines is envisaged, with the performance of some work manually. Thus, it is possible to obtain a product with a higher quality than that of an analogue produced by a handicraft method, but this option is inferior to the automatic production of metal doors in terms of speed and accuracy of the resulting structures. Up to 20 doors can be made per day.

Main stages of production

Whatever method the doors are made of, the production process consists of such mandatory steps as:

• Preparation of materials;
• Frame assembly;
• Construction welding;
• Installation of fittings and protection elements;
• Filling the space inside the structure;
• Door upholstery and painting.

Materials for manufacturing

Metal doors can be made of profile high-quality materials: corners, pipes rectangular section or bent profiles. In the latter case, certain profiles are formed from rolled metal sheets. In this case, the thickness of the sheet should not exceed 2 mm.

Tip: Do not use a large sheet thickness. In this case, very heavy doors are difficult to open / close, the hinges will wear out quickly due to the high load on them.

Necessary fittings and protection elements:

• Hinges: hidden or hinged (see. ) . For doors weighing up to 70 kg, two hinges are sufficient. Armored structures are best attached to 4 loops.
• padlocks for locks from durable metal thickness from 1.5 to 4.5 mm, installed on locks of cylinder and lever types. These elements protect locks from drilling. Armored pads can be laid on, mortise, magnetic, classic.
• Burglar pins. These small devices are located on the door leafs and enter the frame holes when the doors are closed.
• Eyes of any type.
• Signaling, which can be autonomous, remote.

After familiarizing yourself with all the structural elements of metal doors, you can decide what equipment is required for their manufacture.

Billet Equipment

Before using metal for the manufacture of doors, you must:

• Sort it;
• Check marking;
• Determine the presence of deformations;
• Remove corrosion and scale.

For cutting rolled metal are used:

• Guillotine shears, saws, presses;
• Stationary machines with hand torches or gas cutting;
• Laser, plasma cutting.

For processing blanks in the manufacture of the necessary parts, bending equipment is used. In this case, under the pressure of the press, the metal sheet is given the desired shape: a standard rectangular or arched model. To obtain an arcuate profile of the upper part of the door, the workpiece is passed through a rolling machine. After rolling, the profile is cut into the desired sections.

Burrs are removed from the blanks. This is done manually with a file or on a special filing machine.

Then the blanks are sent for punching holes of different diameters for the installation of locks and fittings, according to the prepared cutting maps.

Door assembly and welding equipment

Tip: To assemble the door leaf, use the resistance welding method to prevent deformation of the door leaf and ensure that there are no welds.

Instructions for assembling and welding the door:

• When welding sheets to the frame, an indent of about 20 mm is left on the front side, which will serve as a door porch;
• To increase the rigidity of the web structure, special stiffeners are installed;
• Simultaneously with the stiffening ribs, door locks are installed in special "technological pockets";
• A seal made of non-combustible basalt slab is mounted between the door leafs;
• Hinges are welded to the assembled door with their own hands. In this case, it is necessary to observe the required gaps between the leaf and the door frame.

The photo shows the equipment used for the manufacture of a metal door in the production workshops of the plant.

To better imagine the entire cycle of manufacturing metal doors, to get to know the operation of the equipment in more detail, you should watch the video in this article.

Processing the door with paints and varnishes

The assembled metal door goes to the area for painting. The coating is applied to a well-cleaned and degreased surface.

There are three main ways to apply paint:

• Jet flow;
• From a pneumatic sprayer;
• Spray paint in an electrostatic field.

As a coating, paints of various colors are used. Usually it is: nitro paint, powder, hammer or graphite. This allows you to get good protection of the door against corrosion and minor mechanical damage.

The use of special equipment for the production of doors allows us to obtain a high quality structure, which ensures the use of the structure in its original form for many years.

Metal doors are made different technologies, albeit on the same principle. And you need to figure it out. Only in this case can you choose optimal model, not focusing only on the advice of consultants in stores. Here is the basic information about the production of doors. Information and samples for the article were provided by the company for the production of steel doors "T-Stal".

Equipment and materials

Sheet steel, profiles or corners are used as materials. different sizes and thickness, a set of accessories ( door hardware: hinges, handles, locks, eyes, etc.). The quality of a door depends both on the strength and thickness of the steel, and on the quality of the fittings (first of all, locking mechanisms).

Materials are processed on equipment of various types:

• Automated. Such equipment is used by enterprises that produce more than 200 doors per shift.
• semi-automatic. These are cutting machines welders, sheet bending presses, painting booths. In semi-automatic production, the reject rate is lower, but the productivity is also lower - up to 17-20 products on one line.
• Mechanical. This is a set of hand tools: a grinder, turning and milling machines, a special guillotine, etc. Such equipment is rarely used. In enterprises, semi-automatic machines are more often preferred.

Automated lines allow you to produce more products per day, thereby reducing its cost. However, the percentage of defects in such enterprises is high, and with inadequate quality control, the buyer may reveal defects.

Production process

Conventionally, the production of metal doors can be divided into four stages.

1. At the first stage, a box and a canvas are made. The box is outer part products, which will subsequently be inserted into the doorway, and on which the canvas itself will be hung. They make it from the corner. The corners are welded or bent. The leaf is that part of the door in which the lock is installed, and which performs protective functions. It is made in this way: a frame is created from a corner (stiffening ribs can be used), then a sheet of steel is welded to the frame on one or both sides.
2. At the second stage, hinges are installed on the box and the canvas, carefully checking the mounting points. Holes are made in the canvas and corners for fittings and a lock.
3. At the third stage, the product goes to spray booth where it is being processed. Processing is needed for any metal doors, regardless of what finish will be used in the future.
4. At the fourth stage, fittings are installed and the canvas is trimmed from the inside and outside. During the finishing process, the door can be insulated and seals installed.

The finished product is packed and sent to the warehouse, and then for sale.

Doors are made to order in approximately the same way, however, the dimensions and sketch of the customer are used here.

How to choose a door

Appearance, the brand of the door and fittings, the number of locks - that's not all you need to pay attention to. Be sure to check out:

1. How thick was the steel used for the door leaf. Too thin canvas will break through even with a knife, and too thick will make the door heavy.
2. What is the thickness of the steel in the corners that were used for the frame and box. The strength of the structure depends on this.
3. Were seals used, and was there any insulation. A door without these elements will freeze through in winter and let in sounds. You can’t put it in an apartment or in a private house.

As you can see, it is enough to know the basics of door production technology in order to choose the right model.