Designing the Assembly and Welding Section of Wedge Gate

Contents

CERTIFICATE PROJECT STATEMENT

INTRODUCTION

SCHEMATIC SYMBOLS

1. DESIGN INPUT

1.1 Purpose, design and operating conditions of gate valve

1.2 Evaluation of Constructability

1.3 Selection of structural material and evaluation of its weldability

1.3.1 Main Material Selection

1.3.1 Weldability Assessment

1.4 Analysis of drawbacks of basic version of basic design manufacturing technology

2. DEVELOPMENT OF TECHNOLOGY FOR ASSEMBLY AND WELDING OF GATE VALVE WITH WEDGE GATE

2.1 Proposed version of basic technology of article manufacturing

2.2 General Assembly Requirements

2.3 Selection of modern welding methods

2.4 Justification of welding materials selection

2.5 Evaluation of process strength and structural changes of welded joints based on calculation of thermal mode of welding

2.6 Calculation of parameters of welding modes

2.7 General Welding Requirements

2.8 Development of technology for welding joints providing minimum level of residual (welding) stresses and strains

2.9 Selection of control methods and scope

3. ECONOMIC PART

3.1 Calculation of basic technology of valve with wedge gate

3.1.1 Initial data for calculation

3.1.2 Area Welding Rationing

3.1.3 Manual arc welding rationing

3.1.4 Automatic flux welding rationing

3.1.5 Calculation of the required quantity of equipment in the area

3.1.6 Determination of process cost

3.1.7 Determination of costs for basic materials

3.1.8 Determination of welding materials costs

3.1.9 Process Power Costs

3.1.10 Determination of wages of the main workers in the site

3.1.11 Determination of equipment maintenance and operation costs

3.2 Calculation of proposed technology of valve with wedge gate

3.2.1Installation of welding works in the area

3.2.2Manual arc welding

3.2.3Adjustment of automatic welding under flux

3.2.4 Calculation of required quantity of equipment in the area

3.2.5 Determination of process cost

3.2.6 Determination of costs for basic materials

3.2.7 Determination of costs for welding materials

3.2.8 Process Power Costs

3.2.9 Determination of wages of the main workers in the site

3.2.10 Determination of equipment maintenance and operation costs

3.3 Calculation of economic efficiency

4. SAFETY OF LIFE

4.1 Characteristics of production according to the degree of labor safety

4.2 Sanitary classification and characteristics of the designed area

4.3 Fire classification

4.4 Characteristics by electrical safety category

4.5 Technical measures to ensure labor safety

4.6 Calculation of natural lighting of the site

4.7 Calculation of total artificial lighting of the site

4.8 Calculation of mechanical ventilation

4.9 Calculation of grounding circuit

4.10 Environmental impact assessment of production

4.11 Assessment of stability of the facility operation in emergency conditions

5. DESIGN OF SECTION FOR ASSEMBLY AND WELDING OF GATE VALVE WITH WEDGE GATE

CONCLUSION

LIST OF LITERATURE

APPLICATIONS

Summary

The following issues are considered in this diploma project:

- Analysis of fabricability of gate valve with wedge gate for steam pipelines of high-pressure TPP was performed.

- Manufacturing technology has been developed to reduce the time and cost of manufacturing the product.

- Based on comparison, welding methods and methods have been selected.

- Optimal edge preparation shapes, welding materials are selected to ensure high quality of welded joints.

- Equipment that meets modern requirements of welding production is selected.

- Standard equipment has been modernized on the basis of literature review and patent search.

- Efficiency of engineering decisions is confirmed by economic calculation.

- Taking into account the selected equipment, as well as in accordance with the standards of technological design of welding workshops, a plan of the section of assembly and welding of the gate valve was designed, providing direct-flow and irretrievable movement of products.

The diploma project consists of a graphic part of 12 sheets of A1 format, a calculation and explanatory note, including pages of typewritten text, 30 tables, annexes.

Introduction

This diploma project considers the design of the manufacturing technology and the section of assembly and welding of the gate valve with a wedge gate for high-pressure TPP steam pipelines.

The purpose of the diploma project is to design a section of assembly and welding based on technology that meets the modern requirements of the market economy and the modern level of welding production.

In order to achieve this goal, it was necessary to:

- Analyze the shortcomings of the basic manufacturing technology and develop a new version.

- Justify the choice of welding method, shape of preparation, selection of welding materials.

- Define welding mode parameters to ensure high process strength of welded joints.

- Select modern welding equipment.

- Economic calculation to confirm correctness of engineering decisions.

- Develop a plan for the assembly and welding area based on process design standards and BJD codes and regulations, ensuring the maximum possible level of equipment loading and use of production areas.

The following are used as input data for the design:

- Design documentation.

- Fabrication specification.

- Production and technological documentation.

- Results of course projects and pre-diploma practice.

- Results of the literary review.

- Results of patent-legal search.

SCHEMATIC SYMBOLS

BZD - life safety;

RDS - manual arc welding;

ESS - electroslag welding;

OSHZ - near-shore zone;

ZTV - a zone of thermal influence;

ASF - automatic welding under flux;

WPT - powder additive metal;

VO - visual inspection;

CD - color flaw detection;

MPD - magnetic powder flaw detection;

ultrasound test;

RGD - radiographic flaw detection;

ITR - engineer and technician;

MOS - junior maintenance personnel;

OTC - technical control department;

PPE - personal protective equipment;

Efficiency - Efficiency;

PVM - wet dust collector;

Emergency situations;

AHOV - emergency chemically hazardous substances.

Design Input

1.1 Purpose, design and operating conditions of gate valve with wedge gate for steam pipelines of high-pressure TPP.

Gate valves of this type are used as a shutoff device for blocking the flow of working medium in main pipelines for transportation of commercial oil and oil products, as well as in process diagrams of pumping stations and tank farms, with the temperature of working medium from -15 to + 80 ° С. Such gate valves can be operated in areas with temperate and cold climates, as well as in seismic areas up to 9.5 points on the Richter scale. Fabrication and delivery as per specification 3741370020578557297.

gate valve is a vertical vertical device

Technical characteristics:

- Seal tightness: by class B (GOST 954493);

- Environment: oil and petroleum products;

- Working medium temperature: from -15 to + 80 ° С;

- Ambient temperature: from-40 to +40 °C (climatic modification of U1), from-60 to +40 °C (climatic modification of HL);

- Valve resistance coefficient - 0.24.

- Type of control: electrically driven;

- Service life: not less than 30 years;

- Time of gate valve opening by electric drive 47sec.

This gate valve is made of 15X1MFL steel.

The general view of a latch shiberny is graphically presented on sheet 1502.D13.836.01.00SB.

1.2 Evaluation of fabricability of gate valve

From the point of view of procurement operations in mass production, a wedge valve is a technological product. This is due to the fact that the use of manual non-mechanized labor is limited in the performance of procurement operations. Part of the parts has large dimensions.. Subsequent machining, edge preparation is carried out on a milling machine. Most parts require special edge preparation, which reduces the processability of the device. Somewhat reduces the processability and the need for the use of lifting and transportation equipment.

From the point of view of assembly and welding operations pfldb; rf is technological. This is because most welds are located in accessible locations. Almost all seams are made in horizontal position. The cylindrical shape of the apparatus facilitates the use of semi-automatic welding and reduces the consumption of welding materials .

1.4 Analysis of disadvantages of basic manufacturing technology

The basic manufacturing technology and design of the gate valve with a wedge gate was developed during course projects in the disciplines of RIPSK, PSK. When undergoing pre-diploma practice and analyzing previously developed materials, I concluded that it was necessary to change the basic technology and design, since the use of cast blanks in mass production is very expensive. In particular, RDS ring seams were replaced with ASF, welding in Ar medium for other seams, which makes it possible to increase the processability of the welding process. It is proposed to apply separate assembly of case from two forgings with welding of guides instead of solid casting. A welded version of the production of the bugle is also offered instead of whole casting, from cheaper materials. This improves the processability of the design and reduces the consumption of welding materials, avoids multiple casting defects.

The proposed technology for making a gate valve with a wedge gate DU250 is presented on sheets 1502.D13.836.05.00SB and 1502.D13.836.06.00SB of the graphic part of the diploma design.

Development of technology for manufacture of gate valve with wedge gate

2.1 Proposed version of basic technology for manufacture of gate valve housing

2.1.1 Manufacture of gate valve housing with wedge gate.

- to make preparation of the case from steel 15H1MFL in the form of forgings

- perform preliminary machining of forging for performance of ultrasound control.

-heat the housing sections for bushings welding.

- perform UZD-check of body blanks

- perform mechanical treatment of body blanks for welding

2.1.2 Fabrication of cargo lugs.

- cut out 15X1MFA steel sheet by thermal cutting of eyelets.

-Reserve the edges for welding.

- perform mechanical treatment of eye holes.

2.1.3 Manufacture of bushings.

- to make preparation of the sleeve of steel 15H1MFL in the form of forgings of Dn =400, Dvn =200, L=250.

- perform preliminary machining of forging for performance of UD-check.

- perform UZD-check of bushing blanks

- perform mechanical treatment of bushing blanks for welding

-heat the bushing sections for welding to the housing.

2.1.4 Assembly-welding of gate valve housing

- assemble the joint of the ring seam, set the clearance, eliminate edge displacement.

- weld ring seam by ASF method with accompanying heating.

- to spend a vacation at °C T=680. Up to 300 ° C heating rate 30 ° C/h. The holding time is 5 hours. Cool in the air.

- grind the welds.

- perform inspection of joints by SPD and RGD.

- perform mechanical treatment of body blank assembled for guide welding.

- cook the guides with accompanying heating.

- perform welding of process eyes.

- perform final mechanical treatment of the housing

2.1.5 Manufacturing of wedge gate bolt.

- produce casting of 35L steel bugle rib blank.

- cut off the runners and chop the slag crust.

- check the casting geometry.

- perform mechanical treatment of ribs with edge preparation.

- check geometry after machining.

- from sheet steel rolled stock 09G2C thermally cut the workpiece of the support ring of the bugle.

- check the ring workpiece geometry.

- perform mechanical treatment of the support ring.

- check geometry after machining.

- make forging of upper bushing of yoke from 09G2S steel.

- from Ø325 × 20 pipe thermally cut the ring blank of the middle bushing of the bugle.

- perform mechanical treatment of the workpiece for welding

- assemble the welded version of the upper bushing of the bugle on the elements.

- perform welding of upper bushing of yoke.

- check geometry and quality of welded joint.

- grind the welds and check the geometry of the bugle after welding.

- perform ultrasound of seams.

- perform mechanical treatment of the bugle after welding.

2.1.6 Wear-resistant build-up of plates and seats.

- apply protective layer on working surface of seats and plates.

- perform check of SPD

2.2 Features of assembly-welding.

The quality of the seams to be welded depends to a large extent on the surface condition of the edges to be welded. The preparation of the edges for welding consists in careful cleaning of them from rust, scale, dirt, oil and other foreign inclusions. Cleaning is carried out by steel rotating brushes, hydraulic jet and shot blasting methods, abrasive circles, etc. Moisture and condensate formed at reduced temperatures must be removed by heating or blowing with hot air.

During assembly, it is important to maintain the necessary clearances and alignment of edges, groove angles and edge blunting, since otherwise the formation of non-blazes or burns is possible. The values of clearances and offsets (excursions) when assembling different joints at different metal thicknesses are regulated by the corresponding standards. The accuracy of the assembly is checked by templates, measuring rulers and various kinds of probes. Assembly is carried out in special devices or on reconciled racks. Temporary attachment of parts is performed by strubcins, clamps or assembly tacks .

The assembly assembled by means of tacks shall have the rigidity and strength necessary to remove it from the assembly and transport it to the welding site and to reduce welding deformations. When assigning the dimensions and arrangement of the tacks, the need to prevent their harmful effect on the quality of the welded joints and the operability of the structure is also taken into account. In order to assemble the joint on the grips, their length must be 5080 mm, and the section must be about 1/3 of the seam section, but not more than 2530 mm2. The distance between the tacks is 150500 mm. Tacks shall be located in places where they will be completely digested when laying the main seams. Before welding, all tacks must be thoroughly cleaned from splashes of molten metal .

When assembling parts from steels, temporary technological fasteners from steel of the same grade as the assembled parts should be used. The surface of the parts in the places of welding of the fasteners must be previously cleaned from all types of contaminants. Process fasteners after performance of their functions are completely removed by oxygen or air-arc cutting without a recess in the main metal with subsequent grinding of the surfaces of the parts until cutting traces are removed [2].

During assembly and welding operations, special devices and techniques are used to increase assembly accuracy, reduce warpage of the product and other welding deformations.

Assembly of ring joint of base and shell is performed in vertical position using centering conductor.

In order to reduce deformation and displacement from welding, it is necessary to assign minimum volumes of weld metal; The sections of the corner seams should be taken according to the strength calculation or in accordance with the recommendations on minimum seam legs; to use welding methods with minimum heat deposition; welding is performed by diametrically opposite sections.

In welding of angular seams electrode is inclined by 3045 ° from vertical across connection. Welding is carried out with vertical electrode or with inclined forward angle up to 15 °. The arc is directed slightly (up to 1 mm) to the lower shelf or to an angle. When welding metal of different thicknesses, the electrode is directed towards a sheet of larger thickness to increase its penetration, prevent burning of the sheet of smaller thickness and reduce residual welding stresses.

In accordance with the developed technology and recommendations of CJSC CHZEM, normalization and high tempering are used as heat treatment.

In case welding preheating and high tempering are used. High tempering - heating of tempered steel to temperatures of 680 ° C, holding at a given temperature and subsequent cooling at a certain rate. High tempering creates the best ratio of strength and toughness of the steel.

2.3 Selection of welding methods and methods

Based on the conditions of operation, purpose, material used in the manufacture of the structure, it is allowed to use the following types of welding for the welding of the device: manual arc welding (RDS), automatic flux welding (ASF), electroslag welding (ESS), semi-automatic welding in Ar medium and its mixtures [17.18].

Manual arc welding. By this method, structures are welded in all spatial positions, from different grades of steels, in cases where the use of automatic and semi-automatic welds is not possible, for example, in the absence of the required equipment. The benefits of RDS also include:

Possibility of welding in any spatial position;

Possibility of stable arc burning and melting of electrode at direct and alternating current;

Sufficient protection of molten metal;

The ability to produce well-formed rollers;

Disadvantages include high probability of defects in the welded joint, low process productivity, high consumption of welding materials, poor sanitary conditions of welding, high heat deposition in the welded article, which leads to post-welded deformations of the article. The control of the feeding speed and the welding speed is carried out by the welder manually, therefore, the quality of the weld will depend on the practical skills of the welder.

Automatic flux welding. During welding, the electrode departure is much less than with RDS. Therefore, it is possible not to fear overheating of the electrode and separation of the protective coating, to increase the current strength several times. The productivity of flux welding is 1015 times higher than with RDS. This is achieved by: increasing the value and density of the welding current, increasing the surfacing coefficient, increasing the depth of penetration of the welded metal, increasing the welding speed, reducing the machine time of welding. The melting of the electrode and base metal occurs under a flux that reliably protects them from the environment. Flux contributes to the production of pure and dense weld metal, without pores and slag inclusions, with high mechanical properties and homogeneity of the weld metal in chemical composition. There is practically no loss of carbon monoxide and spraying of electrode metal. The working conditions of the welder are improved, that is, when welding under flux, there is no need to protect the welder from the influence of an arc. The development time of flux welding is reduced compared to RDS. The welding process is fully mechanized. The disadvantages of ASF include the lack of visual control over the welding bath, the possibility of welding only in the lower position due to the possible flow of flux and metal when the seam plane deviates from the horizontal by more than 10150, and the limited maneuverability of the machines.

Electroslag welding. ESS is a fairly universal welding method in terms of the kind of current, types of electrodes, and field of application. This welding process is equally successful at both DC and AC. The electrode melting process in electroslag welding, as in mechanized flux welding, is self-regulating, i.e. the length of the interelectrode gap is automatically set. Therefore, in practice, the electrode feed rate and the welding voltage are usually set, and the melt rate automatically becomes equal to the feed rate. The advantages of ESS are:

- High melting efficiency. The electroslag process allows a load on the electrode up to 1000A, which is impossible during arc welding.

- High efficiency of the process. Power consumption decreases by 1015%, flux - by 20 times compared to arc welding.

- High stability of the process: current density at the electrode 0.2300 A/mm2 is permissible.

- Low stability of the process to the quality of edge preparation.

- Good quality air protection, no worse than arc welding under flux, and with additional protection of the slag bath with a gas jet - better.

- The possibility of welding in one pass of almost unlimited metal thickness, different joints.

The disadvantages of electroslag welding include:

- Overheating of the weld metal and near the seam zone and the resulting reduction in metal toughness.

- Possibility of welding mainly in vertical position.

- Necessity of forced formation of seam.

Welding in Ar and its mixtures. Compared to RDS, welding in protective gases has the following advantages:

Possibility of mechanization of welding works during short seams;

Reduced warpage of articles due to increased heat transfer, cooling action of protective medium and increased rate of molten metal crystallization;

Simplicity of the welding process and technique (welders master this method in 3-5 shifts);

Higher productivity due to automatic wire feed with satisfactory weld quality;

Low sensitivity to pore formation compared to the process of welding with electrodes with fluoristocalcium coating and flux welding of metal coated with scale, rust and other contaminants;

Reduced gas content in the seam;

Possibility of direct observation of welding process and location of joints;

Possibility of welding in hard-to-reach places;

Cheapness of the process;

Disadvantages: due to the high oxygen content in the arc atmosphere, it is necessary to deoxidize the weld metal during the welding process. Deoxidizer elements are introduced into welding bath through electrode wire.

Thus, having analyzed all the advantages and disadvantages of the above-mentioned methods, we choose an automatic flux welding for welding the annular seam of the structure body, and a method of welding in the environment of protective gas Ar for welding the ribs and eyelets. For locksmith assembly and build-up of seats and plates, welding of bugle - RDS method.

2.9 Selection of weld inspection methods

2.9.1 Internal defects generated during welding by melting of welded joints

Internal defects of welded joints include defects that are not detected by external inspection of the welded joint of a part, assembly or article. The type, nature and size of internal defects depends on the welding methods.

Cracks - partial local destruction of the welded joint. In the built-up and base metal, cracks occur as a result of the development of intrinsic stresses that can occur in the metal due to the following reasons: casting shrinkage or structural transformations or changes in volume as a result of the transition of the metal from a liquid state to a solid state; uneven temperature distribution during heating or cooling of the welded object; welding of parts from structural alloyed steels in rigidly embedded circuits; high cooling speed during welding of carbonaceous steels, which are prone to hardening in air; welding at low temperatures reducing the plastic properties of the metal; clogging of the main and additive metal with harmful impurities of sulfur and phosphorus; presence of other defects in welded joints, which are stress concentrators that cause crack formation, etc.

Depending on the temperature conditions under which cracks occur, they are divided into cold ones occurring at a temperature of up to 300 ° C and hot ones occurring at a temperature of 11001300 ° C.

Depending on the location relative to the weld joint, the cracks are divided into longitudinal and transverse; by location in the welded joint - on cracks in the built-up metal, cracks in the main metal or in the zone of thermal influence.

Depending on the size of the cracks, they are divided into macro cracks having a relatively large size in depth, extent and opening, and microcracks detected by the armed eye.

Depending on the type of stress (compression or tension) that occurs in the elements of welded structures, cracks can be closed, difficult to detect (in compressed elements) or open, clearly visible (in stretched elements).

Crack is the most dangerous and unacceptable welding defect.

Non-weld - no fusion between the weld and base metal (at the root of the weld or at the edge) or between adjacent layers of the weld. In case of non-roving, there is no structural connection between adjacent metal volumes in the welded joint. Non-melt occurs when the molten electrode metal enters the non-molten base metal. On the contact surface of the molten and base metal, a thin oxide film is retained, reducing the adhesion strength between them.

Reasons for the formation of non-veterans:

- insufficient thermal power of the arc (low current, excessively long or short arc); electrodes made of a fusible material, whereby the liquid metal fills the seam on the unfused welded edges;

- excessive welding speed at which the edges to be welded do not have time to melt;

- significant displacement of the electrode on one of the welded edges, when the molten metal runs into the other unalloyed edge, covering the non-welded edge;

a small gap or a small angle of bevel, which makes it difficult to melt the base metal;

- unsatisfactory grinding of edges for welding from rust, scale paint, oil and other contaminants;

- wandering or deflecting the arc under the influence of magnetic fields, especially when welding on a direct current, when the base of the arc column is located in one place, and liquid metal flows to other section of unalloyed metal;

- improper arrangement or too large cross-section of the filler wire laid in the seam, making it difficult to melt the base metal;

- unsatisfactory quality of base metal, welding wire, electrodes, fluxes, etc.

- unsatisfactory operation of welding equipment - fluctuations of welding current and arc voltage during welding;

- low qualification of welder.

Neprovar is one of the most dangerous defects of welding, especially in welded joints operating under the influence of vibration and impact loads.

Pores (porosity) in the weld weld metal are different bubbles (usually spherical in shape) filled with gases. Gas bubbles occur due to intense gas-forming reactions in the metal volume and a high solidification rate which prevents gas bubbles from rising to the surface of the molten weld metal.

The main reasons for the occurrence of pores in welds: increased carbon content in the main metal or in the additive material; increased humidity of the electrode coating, flux or welding operations in wet weather; the presence in some electrode coatings of starch, dextrin and other organic constituents, the decomposition of which may result in saturation of the seam metal with carbon monoxide or hydrogen; poor cleaning of the edges of the welded metal from rust, paint and other pollutants; high welding speed leading to rapid solidification of the welding bath.

Oxide inclusions.

Oxide inclusions (films) can occur in all types of welding. The effect of oxide films on the mechanical properties of welded joints can be stronger than the effect of pores, slag and metal inclusions.

Causes of oxide inclusions: contamination of surfaces of welded edges with rust, oil, paint, etc.; poor cleaning (or separability) of slag from the surface of the seam during multilayer welding; rapid cooling of a bath of liquid metal (small layer of slag coating), which makes it difficult to float larger inclusions; high density or refractory slag; poor-quality electrode coating (the coating gives a viscous thick slag, or it is applied more than laid); low qualification of welder.

Technical characteristics of non-standard equipment

Non-standard equipment includes an assembly conductor designed by me, consisting of a guide rod, bolt-stop devices, channel supports.

The conductor is designed for rigid fixation of the welded product in it, it also serves as a check template for correct assembly of seats.

When assembling the wedge valve body, first, the upper sleeve of the body is installed on the conductor, then a tee assembly is installed, the cone-shaped upper part of the conductor is a template of the gate. Assembly on the conductor is carried out according to the drawing 1502.D13.836.09.00SB.

Welding Head Upgrade

The modernization of the welding head consists in replacing the welding wire feed mechanism with the one proposed in the description of the invention (Patent No. 505537, CL B 9/12, 1974) in order to increase the stability of its supply to the welding zone .

invention relates to arc welding and can be used in machines and semi-machines for welding with a melting and non-melting electrode.

The purpose of the invention is to simplify the design and increase reliability of the device for uniform supply of welding wire.

Proposed target is achieved by the fact that drive element is made in the form of cylindrical roller with screw thread on external surface along the entire length of roller.

In addition, in order to increase reliability in operation by periodically cleaning the screw thread of the driving element from chips and impurities, at least one projection is made on the pressing roller, which is located in the cutting groove and has a mating profile.

The figure shows this device in section.

Proposed device comprises body 1 with guide mouthpieces 2 and 3, pressure roller 4 with axis 5 and drive element 6 representing solid cylindrical roller with screw thread on outer surface. Free end 7 of drive element 6 is connected to drive 8. Axle 5 of pressing roller 4 is connected with lever 9 on which spring 10 is located. Adjusting screw 11 is installed coaxially with lever 9 in housing 1. Protrusion 12 is made on pressing roller 4, profile of working end of which repeats profile of cavity of screw thread of driving element 6.

The device operates as follows.

Welding wire supplied depending on direction of rotation of drive 1 and through guide mouthpiece 2 or 3 is supplied between pressing roller 4 and driving element 6. The pressing roller 4 presses the welding wire against the screw threads on the outer surface of the driving member 6.

The pressing force of the welding wire is controlled by the adjusting screw 11. When the driving member 6 is rotated by the actuator 3, a force is generated to move the welding wire in a direction parallel to the axis of the driving member 6. In order to improve the bonding of the welding wire to the coils of the driving member 6, a plurality of pressing rollers 4 may be arranged in series one after the other. The working end of the projection 12 on the pressing roller 4, when the driving element 6 rotates, periodically enters the screw thread cavity, as a result of which it is cleaned from chips and impurities.

Design of drive element in the form of solid cylindrical roller with screw thread on side surface makes it possible to simplify design of device. In addition, the reliability of the device is improved due to the lack of clogging of the screw thread with chips and the low sensitivity to violation of the accuracy of its manufacture. The cost of manufacturing the device will decrease by 4-5 times with a significant increase in convenience. Design of the feeder of a wire is shown in the drawing 1502.D13.836.11.00SB.

Welding torch

invention is related to arc welding in medium of protective gases and may be used in machines and semi-machines for welding with melting and non-melting electrode.

The purpose of the invention is to improve the quality of welded joints by increasing the stability of protective gas flows.

In the proposed device additional gas flow is formed due to interaction of these two flows. In this case, a turbulent flow is formed. This flow does not have the negative effect that is observed in known devices, but on the contrary, when in contact with the parts to be welded, shakes the welding products and throws them out of the welding zone.

The detailing of a torch is shown in the drawing 1502.D13.836.11.00SB.

The device operates as follows.

Electrode wire from tube 11 is fed to article through its guide channel of tip 3. The protective gas from the tube 10 enters the manifold 9, from where it is distributed to the main and additional streams. At constant pressure in tube 10, redistribution of gas volumes between flows is performed by throttling using screw 12. If you reduce the section of the channel supplying gas to the main stream, then the volume of gas entering the additional stream will increase, and therefore the speed of the additional stream forming the arc will increase. Both the main and additional gas flow at the exit of the burner is swirled by the helical grooves 5 and 6 present on the conical surfaces of the tip 3 and the nozzle 4. Vortex-like swirling of additional flow makes it possible to form stable bell forming arc, and vortex-like swirling of main flow in the same direction reduces interference created by main flow and improves operating conditions of additional flow. At the same time, the lifting angles of the screw grooves for the main flow should be greater, because the speed of the main flow is much less than the speed of the additional gas flow. In addition, vortex-like swirling of the main gas flow improves the protection of the arc from the workshop atmosphere.

The burner improves arc stability and quality of the welding bath, reduces the consumption of protective gas and improves the working conditions of welders.

Process Cost Determination

Process cost of welding works includes costs for basic materials (SM), welding materials (CER), process electric power (SE), wages (CPS), expenses for maintenance and operation of equipment (SDS) [12].

Conclusion

1. The shortcomings of the basic manufacturing technology were analyzed and a new version was developed on the basis of the analysis.

2. Welding methods, edge preparation shapes, welding materials are reasonably chosen.

3. Based on the comparison of technical and economic parameters, it has been proved that the method of automatic welding under flux has an advantage over others in the manufacture of a gate valve with a wedge gate.

4. Welding mode parameters are selected to ensure high technological strength of welded joints.

5. It is shown that the developed manufacturing technology can be implemented using modern existing equipment for assembly and welding. A reasonable selection of equipment was made that meets the requirements of welding production.

6. The validity of engineering solutions selected in the diploma project is confirmed by economic calculation. It is shown that the effect of implementing the ASF method for manufacturing the product is 48600 million rubles.

7. A plan for the assembly and welding section of the wedge gate valve has been developed on the basis of technological design standards for welding workshops and BZD norms and rules, ensuring the maximum possible degree of equipment loading and use of production areas. Direct-flow, irretrievable movement of cargo flow is provided on the site.