Body bead assembly and welding

Contents

CONTENTS

Introduction

General part

Characteristics of the enterprise

Characteristics of welded structure and its purpose

Process Part

Characteristics of welded structure material

Evaluation of material weldability

Selection and justification of process diagram

fabrication of the structure

Selection and characterization of procurement activities

2.

Selection and justification of procurement methods

2.

Equipment characteristics for procurement operations

Assembly Assembly

2.

To Select How to Assemble a Design

2.

Characteristics of equipment and process equipment

for assembly assembly

Welding of structure

2.

Characteristics of welding method

2.

Selection and characteristics of welding materials

2.

Calculation and selection of design tack and welding modes

2.

Selection and characteristics of welding equipment and tooling

Quality control of welded structure fabrication

Assembly-Welding Routing Process

designs

Organizational Part

Structure and technological equipment of assembly and assembly

welding section

Technological preparation of welded production

designs

Economic part

Rationing of welding time

Calculation of material costs for welded production

designs

4.

Calculation of welding materials consumption

4.

Calculation of welding materials and electric power

Calculation of team qualification and calculation

wages

Calculation of manufacturing cost of welded structures

Occupational safety

Organization of safety works at

site

Fire fighting measures

Occupational safety and environmental safety measures

at the enterprise

Conclusion

Bibliography

Introduction

Welding is the process of obtaining a permanent joint by heating the joined edges to melt, or bringing the heating to a plastic state and subsequent compression, or mechanically acting on the welded materials (by compression). In 1882. Benardos conducted the experience of welding metal using the heat of an electric arc, a carbon rod was used as an electrode. In 1888 Slavyanov welded the metal using a metal rod. He proposed a method of flux welding, invented the first welding generator, invented the first automatic regulator of the length of the welding arc.

Also, welding is one of the most common process of joining materials, thanks to which many new products, machines and mechanisms have been created. Welding is one of the leading technological processes both in the field of mechanical engineering and in the construction industry and metallurgy. Currently, welding production is an independent industry, used both in construction and in mechanical engineering and metallurgy. For the further development of welding, a number of issues need to be solved (for example, the development of new designs for welding machines, welding devices and welding materials, etc.).

Welding of many types of metal structures made it possible to effectively use billets obtained by rolling, flexible, stamping, casting and forging, as well as metals with various physical and chemical properties. Welded structures, compared to cast, forged and riveted ones, have great strength, lower weight and are less labor intensive to manufacture. With the help of welding, permanent joints of almost all metals and alloys of various thicknesses are obtained, along with structural carbonaceous and low-carbonaceous steels, special steels are increasingly welded, light alloys based on titanium, molybdenum, zirconium and other metals, as well as heterogeneous materials.

There is no industry where welding, cutting of metals or their surfacing on the surface of parts is used.

Fundamental research on the development of new welding processes, welding materials and equipment is carried out by many research organizations, higher educational institutions and large industrial enterprises. In recent years, welders have been working to create resource-saving technologies that reduce electricity consumption, reduce material consumption, and rationally use welder labor in the manufacture of various structures, machines, and products.

During welding, it became possible to create structures with high performance. At the same time, the advantages of welded joints allow them to be widely used in general-purpose structures. The use of welding saves materials and time during the manufacture of structures. At the same time, great opportunities for mechanization and automation of production are opened, prerequisites for increasing productivity are created, working conditions of workers are improved, and so on.

The development of scientific and technological progress is constantly taking place, along with it there is an expansion of the capabilities of welding parts of various thicknesses of materials, and in this regard the set of applied types and methods of welding is changing.

The quality and reliability of the finished structures and the overall production efficiency depend largely on the progressivity of the welding processes used and the quality of these works.

Of the most developing areas in welding production are the widespread use of mechanized and automated arc welding. These issues are solved by mechanization and automation of both the welding processes themselves, in other words, the transition from manual work of the welder to mechanized, and complex mechanization and automation, covering all types of work related to the manufacture of welded structures and the creation of in-line and automatic production lines. At the same time, it is important to create special welding equipment and technological equipment.

The conditions for welding have expanded significantly: welding is carried out in high temperatures, radiation, underwater, in space, and so on. Welds are made in any spatial position.

Due to the improvement of equipment, new types of welding begin to be introduced in production, such as: laser, electron beam, ion, light, diffusion, ultrasonic, friction, explosion. Arc and contact welding capabilities are greatly expanded.

Currently, plasma welding and metal cutting are widely used. Air-plasma cutting is very promising, in which ordinary atmospheric air serves as the working gas. For small metal thicknesses, micro-plasma welding at low currents turned out to be valuable when the plasma jet has the size and shape of a sewing needle.

Quality control of welded joints plays an important role in the manufacture of welded products. Various destructive and non-destructive inspection methods are used to control the quality of welding.

NDT methods make it possible to detect defects without damaging the objects of control. A destructive control method detects defects by destroying a structure, assembly or article.

In the current conditions, when there is a continuous complication of structures, the volume of welding work is steadily increasing, the correct conduct of technological preparation of production plays a great role, which largely determines its labor intensity and time of development, economic indicators, the use of mechanization and automation tools.

The increase in the technological level of production, the commissioning of complex welding equipment are constantly associated with an increase in the requirements for the level of training of workers - welders.

The purpose of the diploma project is to develop the technological process of manufacturing the welded structure of the "transverse side," which should be a product of high reliability, in terms of strength and durability of work.

In order to ensure increased reliability of the design, it is necessary to solve the following problems:

Develop the most efficient design assembly and welding process

provide for the possibility of using high-performance equipment, technological equipment and cutting tool;

calculate the economic part;

Define measures for environmental protection and life safety of the workshop employees.

General part

1.1 Characteristics of the enterprise

Chelyabinsk Tractor Plant - URALTRAK (CHTZ) is an industrial association for the production and sale of a wide range of wheeled and tracked road construction equipment (bulldozers, pipe laying, frontal loaders), spare parts and other high-tech machine-building products.

Consumers of ChTZ products are thousands of enterprises in Russia, CIS countries and far abroad of various branches of activity, such as oil and gas, mining, construction, forestry and others, as well as state ministries and departments of various countries.

The production potential of the plant provides a complete technological cycle for the creation of engineering machines: from procurement to assembly and testing.

At ChTZ, modern technologies are widely used: heat treatment in the medium of inert gases, sheet bending, machining on CNC machines and processing centers, robotic welding, plasma, laser metal cutting, etc.

The total number of process equipment units is about 18,000 pieces.

The association includes foundry, blacksmith, press-welding, mechanical assembly and other factories.

Number of employees - 5,200 people

The production area occupied by ChTZ is 1.2 million m2.

In certain segments of the Russian market, such as bulldozers and pipe builders of the most popular classes, ChTZ stably holds a leading position. Hundreds of cars are exported annually. In addition to the CIS countries, over the past few years, equipment with the ChTZ brand has been supplied to 16 countries abroad.

To ensure the high quality of the weld and weld joint, appropriate control is required.

Quality control is carried out at all stages of the process. Thus, three types of control can be distinguished:

preliminary control;

operational control;

control of finished welding connections.

Welding materials (welding wire, electrodes, gases, fluxes) as well as welding and equipment (instrumentation, tools) are checked at the preliminary inspection stage. The same stage includes the implementation of measures to check the qualifications of welders, engineering and technical workers and other workers employed in the production and control of welding operations.

At the stage of post-operation inspection, the preparation of parts for welding is checked, the welding mode and the correctness of seaming are monitored. At the same time, the state of the equipment, the quality of additive materials and the serviceability of instrumentation are also monitored.

Check of finished welding joints is performed at the end of welding process or after technical inspection of finished product.

The methods of quality control of welds are usually divided into two main groups:

destructive control - ethocontrol, at which the sample is destroyed;

NDT - welding connection shall not fail.

They try to apply destructive control in practice much less often, but sometimes they cannot do without it.

Both groups of control methods are regulated by the relevant GOST and are divided into types of control.

The types of control are: external inspection, ultrasonic inspection, capillary inspection, magnetic inspection, inspection of welds for permeability and so on.

The shift duration is 8 hours. The work shift begins at 08:00 hours. End of shift 17:00 hours. Lunch break from 12:00 for 60 minutes.

For the assembly and welding workshop of the enterprise, a five-day working week with two days off was adopted, if desired, additional work on the day off. The average number of working days per year for a five-day working week is 255 working days.

Process Part

2.3 Selection and substantiation of design process diagram

A process plan is a part of a production process that contains actions to change the state of a work item.

The assembly process is characterized by a certain amount of labor, as well as a certain time, called the assembly cycle, during which this process is carried out. The labour intensity of the assembly depends on the degree of perfection of the design, the development of the technological process, the degree of the assembled elements and their accuracy, the energy content of the equipment and equipment.

With an increase in the technical armament of labor and an increase in the volume of production during the transition from single to serial and mass types of production, more thorough development of technological processes takes place.

Mass production is a type of production characterized by a limited range of products manufactured or repaired in periodically repeated batches and a relatively large volume of production.

The process is developed for the manufacture or repair of the product, or for the improvement of the existing process. The technological process being developed should be progressive (technological process progressiveness is evaluated by the indicator established by the industry process certification system) providing safety requirements, improving labor productivity and quality of parts, reducing labor and material costs.

2.4 Selection and characteristics of procurement operations

2.4.1 Selection and justification of procurement methods

Procurement operations involve production of blanks and finished parts for welded assemblies in various ways. When performing procurement operations, the following types of metal processing are used:

markup;

mechanical cutting and cutting;

Edit workpieces

grinding of burrs, removal of scale, rust before welding.

Cutting - a locksmith operation to divide an entire piece (workpiece, part) into parts. It is carried out without removing chips: with pieces, scissors and pipe cutters and with removing chips: with legs, saws, cutters and special methods (gas cutting, anodic-mechanical and electric spark cutting, plasma cutting).

Straightening eliminates irregularities and warping on the surface of the material and undulations along the edges. Material is controlled after cutting of parts after bending, rolling, hardening, tacking, welding, soldering of parts and at the end of assembly.

Any contaminants can be mechanically removed, but most often the metal surface is cleaned of rust, scale, old paint and other old coatings.

The following cleaning methods are used: grinding, quartz, tumbling, pneumo and hydroabrasive treatment.

The cleaning method for this part is grinding.

2.5 Assembly of structure

2.5.1 Selection of construction assembly method

Assembly is one of the most critical activities. The quality of the welded structure depends to a large extent on the quality of the assembly. For example, an assembly with increased gaps, with mismatch of the edges to be welded in thickness, requires the application of seams with a large volume of weld metal, which leads to increased residual deformation of the structure. The assembly operation involves assembling and tacking parts before welding.

For thin metal and short seams, the tack length is not more than 5 mm, and the distance between them is 50100 mm. Thick metal, with an average length of seams, is collected by tacks 2030 mm long, with a distance between them of 300500 mm.

Figure 1.2, 1.3 shows the connection assembly diagrams that are present in this design.

2.5.2 Characteristics of equipment and equipment for structural assembly

The main purpose of the assembly equipment is to fix and secure the assembled welded assembly in a given position. For this purpose, special magnetic detectors Start 100 LBC are used.

The devices shall meet the following requirements:

ensure accessibility to the places of installation of parts to the handles of clamping and fixing devices;

ensure an advantageous assembly procedure;

must be strong and rigid enough to ensure that the parts are accurately fixed in the required position and prevent their deformation during assembly;

provide free access during article check;

ensure safe execution of assembly works.

2.6 Welding of structure

2.6.1 Characteristics of Welding Method

Welding operations allow you to finally attach the assembled parts, assemblies and structures and obtain products that meet design and operational requirements. The choice of the number and sequence of welding steps depends on the nature of the production, the geometric dimensions of the structure.

Based on the features of the welded structure "Furnace Bottom Stand Wiring," semi-automatic welding in the medium of protective gases was chosen.

The main types, structural elements and dimensions of welds and joints are regulated by the following regulatory documents:

GOST 1477176 - for welds performed by welding in protective gases;

GOST 526480 and GOST 1153475 - for manual arc welding joints;

GOST 871379 and GOST 1153375 - for joints performed by automatic and semi-automatic welding under flux.

Semi-automatic welding is used in the manufacture of welded structures.

Semi-automatic welding - mechanized arc welding with a metal melting electrode (wire) in the environment of protective gases. The method is also known as MIG/MAG welding. Depending on the type of protective gas used, welding in inert gases (MIG) and active ones (MAG) are distinguished. As active gases, welding in carbon dioxide medium is mainly used. Unlike manual arc welding with coated electrodes in mechanized welding, electrode feed into welding zone is performed by means of mechanisms, and welder moves torch along seam axis and performs oscillatory movements by electrode as required.

Advantages of semi-automatic welding include:

relatively easy to obtain high-quality welded joint, including for thin-walled welded structures;

high efficiency of welding by this method compared to manual arc welding, gas welding and other types of welding;

mechanized welding in the environment of protective gases can be carried out in all spatial positions;

absence of fluxes and coatings, and accordingly operations to clean the seam from slag;

the arc during welding in protective gases is more concentrated and stable, therefore the thermal influence zone is minimal;

welding is accompanied by minor stresses and strains;

possibility of complete automation of welding process.

2.7 Quality control of welded structure manufacturing

The welded structure is controlled at the entire stage of its manufacture. We also check the fixture and equipment. According to GOST 1546779, product quality is a set of product properties that determine its suitability to meet certain needs in accordance with its purpose.

After procurement operations, the structure is checked by non-destructive method of quality control of welded joints, which include: external inspection, ultrasonic inspection, inspection for impermeability (or tightness) of the structure, inspection for detection of defects coming to the surface, inspection of hidden and internal defects.

External defects are detected by external inspection of welds: non-penetrations, surges, undercuts, crater, external cracks and pores, displacement of welded edges of parts, burning and the like. Visual inspection is carried out both with the naked eye and with the use of magnifying glass, with an increase of up to 10 times. Ultrasonic flaw detection reveals internal defects: cold or hot cracks, pores, non-metallic inclusions, non-melting, fistula, chewing and overheating.

The dimensions of the section of the finished weld are checked according to its parameters depending on the type of connection. At the butt seam, its width, height, size of the bulge on the side of the seam root (reinforcement of the seam) are checked, in the angular, tar and lap joint - the roll is measured. Measured parameters shall correspond to GOST. The dimensions of welds are usually controlled by measuring tools or special templates (for example: template UShS2, caliper GOST 16689 and so on).

Tightness of welds is controlled by the following methods, capillary (kerosene), chemical (ammonia), bubble (air or hydraulic pressure), vacuumization or gas-electric leaks by seekers.

The occurrence of defects is often associated with metallurgical and thermal phenomena arising during the formation of the welding bath and its crystallization. These defects reduce the strength and reliability of the weld joint, its tightness and corrosion resistance. All this can have a significant impact on the operational capabilities of the entire structure and even cause its destruction. Permissible defects are defined by GOST 2311899.

2.8 Routing process of assembly - welding of structure

The route chart is the technological document containing the description of technological process of assembly welding of knot (including control) on all operations which are carried out in the technological sequence with the indication of data on the equipment, the equipment, material and labor standards.

2.8.1 Critical analysis of existing technology

Currently, the Neftekamsk factory of car dump trucks uses the technology of assembling and welding the Side Transverse product, in which manual and screw clamps are used as clamping elements. They are easy to operate, but low-productivity. To reduce the auxiliary time, it is necessary to partially introduce pneumatic clamps, especially if you want to attach the product in several places.

Welding semiautomat PDG525 (overall dimensions - 470 • 298 • 260 mm) and rectifier VDU504 (1275 • 816 • 940 mm) are used for welding of this structure. The semi-automatic machine and rectifier occupy a significant working area. Therefore, I suggest replacing welders. Currently, industrial plants have begun to produce semi-automatic welding machines in the environment of protective gases combined with a power source. For example, the semi-automatic "PDG280," which is one of the progressive models of semi-automatic machines of this class.

With the existing technology, carbon dioxide of grade I (GOST 805085) with a purity of 99.5% is used as a protective gas during welding. When carbon dioxide is used in its pure form during welding, there is a strong spattering of molten metal, this drawback can be partially eliminated using a mixture of carbon dioxide and oxygen (CO2 + 5% O2) as protection. In addition, the mixture is cheaper than pure gas.

2.8.2 Justification of welding method selection

For the manufacture of various welded structures, the following types of welding are used:

1. Special;

2. Contact;

3. Electric welding by melting.

A special type of welding includes:

1. Plasma;

2. Electric radiation.

These welding methods have a number of advantages and disadvantages, namely:

a) increased labour intensity;

b) bulky equipment;

c) high cost;

d) harmful to the human body.

Therefore, given all these negative properties, special types of welding are not acceptable for welding of this structure.

Contact welding is not possible for design reasons.

Therefore, for the manufacture of the Side Side article, electrical melting welding is most applicable, which is divided into:

1. Manual arc welding;

2. Electroshlak;

3. Flux welding;

4. In a protective gas environment.

In mass or large-scale production, the use of RDS is not advantageous, since:

a) low productivity;

b) high release of harmful substances;

c) high consumption of welding materials.

The use of electroslag welding is not possible, since it is carried out when welding parts of large thicknesses.

Automatic flux welding is considered non-process.

Semi-automatic welding in a CO2 environment is most applicable. With this welding method, the welding wire is mechanically supplied to the welding zone and the weld metal is protected by supplied carbon dioxide. Welding is possible in any spatial position. The effectiveness of the gas protection is affected by the type of weld joint and the welding speed. As the welding speed increases, the protection of the welding bath decreases .

In order to ensure reliable protection of the welding zone and the welding bath from the environment, the distance of the nozzle from the product, the size of the nozzle and the flow rate of protective gas are important. Excessive proximity of the nozzle to the article increases the splashing of the metal, and removal leads to violation of the protection of the welding zone. With existing equipment, the nozzle distance from the article is usually kept within 725 mm.

It has a number of features:

1. High productivity (approximately twice as high as for HDS coated electrodes);

2. A small zone of thermal influence and relatively small deformations due to the high degree of arc concentration;

3. Possibility of welding in any spatial positions;

4. High quality of protection, no need to apply grinding of joints in multi-layer welding;

5. Easy mechanization and automation

6. Availability of welding process monitoring;

7. The possibility of welding metals of various thicknesses (from tenths of a millimeter to tens of millimeters).

Among other advantages that are characteristic of welding in protective gases, welding in a carbon dioxide environment is characterized by high productivity and low cost.

By semi-automatic welding in a carbon dioxide environment, most steels can be welded, satisfactorily welded with other types of arc welding. Disadvantages include increased spraying and not always satisfactory weld appearance. This welding method is quite technological and economical. It is advisable to leave this welding method in the design version.

2.8.5 Selection of methods and parameters of article quality control

In degree design, after the development of the process, it is necessary to establish a quality control method.

There are two types of quality control:

1. Nondestructive

2. Destroying

Consider the destructive type of control, this is for tension, impact toughness, for bending, since the product and its configuration are not suitable for this kind of quality tests, this type of control is not used.

Consider a non-destructive type of testing, it includes visually optical method, ultrasound, rengenkontrol, magnetic methods, leak test.

Visually optical method - always applied independently of other control methods, while detecting only external defects (undercuts, burns, pores). External inspection is in many cases quite informative and is the cheapest and most operational method of control. The appearance of the weld surface is specific to each welding method.

Welded joints are irradiated with X-rays. Reference samples (groove wire, groove stepped) are installed near the seam. Quality assessment is performed by dimensions of groove, wire. Flatness defects are poorly detected and quality information can be documented. The type of control is used in the bowl for the control of critical articles operating under pressure at high temperature.

Ultrasonic inspection mainly reveals flat and volumetric defects, but cannot distinguish non-metallic inclusions from other defects.

With all these methods, the visual optical method is the more appropriate method of control, because it is quite informative and is the cheapest and most operational method of control.

3 Organizational part

3.1 Structure and process equipment of assembly and welding section

The assembly and procurement section includes three operations: procurement, assembly and welding, which are carried out in the same building.

Specialized equipment, complex mechanized flow cutting lines and special non-standard equipment are used. Suspension and floor transport are widely used.

Initial metal is processed at billet section to produce parts of preset articles. Mechanical scissors intended for metal cutting or thermal cutting machine are installed on the section.

The parts are then delivered to the mechanical section, if required by the process. On the section there installed are turning, milling, boring machines for processing end faces of blanks, chamfers for welding.

Grinding is carried out mechanically by sandblasting or shot blasting methods, metal brushes, abrasive or chemical etching.

After the workpieces are manufactured, they are delivered to the assembly. The worker, according to the operating map of the process of assembly and welding of the wire of the bottom stand of the furnace, conducts the assembly of the steel structure.

The assembly section is equipped with assembly plates made of cast iron, on which assemblies are assembled, and there are also special devices for certain structures. Location of parts is fixed by means of tacks.

After assembly, the assembly enters the work station of the welder of the welding section, where welding is carried out according to the drawing. After manufacturing, the assembly unit is transported to the painting shop, then, according to the process roadmap, it is transported to the storage place for further loading.

Warehouses and storage rooms are auxiliary departments of the assembly and welding workshop and are located near the workshop in the production area. Warehouses include storerooms for various purposes. Tool storerooms are designed to store, receive and issue tools, electrodes, welding wire, personal protective equipment and non-bulky devices used in operation, workshop equipment. It also monitors the degree of wear and tear and the selection of degraded tools and devices for exchange for new ones in the central factory warehouse. For the normal operation of the workshop, storage rooms are also required: auxiliary materials, welding materials, workstations, test templates, and so on.

The necessary administrative, office and household premises shall be provided in each assembly and welding shop.

When planning the workshop, the main provisions are taken into account: the location of equipment, workplaces and mechanization facilities according to the accepted technological process; location of production areas of the workshop and auxiliary services, ensuring the largest output of products from the 1st floor area of ​ ​ the workshop, subject to conditions for reliable and safe work of production personnel; uninterrupted arrival of materials, parts and assemblies to workplaces, straightforward cargo flows and shortest ways of moving materials, blanks and products in the process of production using mechanized vehicles, interoperative storage of materials, parts and assemblies, internal and internal transport, approaches to equipment of vehicles; as well as to points of connection of portable equipment and ventilation plants, methods of removal and transfer of parts and products for subsequent operations.

Feeding mechanisms of welding semi-automata are installed on booms of rotary cantilevers. At the welder's workplace, welding is carried out on the plate and only in the lower position with a tap crane.

3.2Technological preparation of welded structures production

The process for welding works during the manufacture of welded structures at industrial enterprises should be developed and executed in accordance with the requirements of the standards of the unified process documentation system (AETD).

The requirements for the technological preparation of welding production and the organization of welding works are established by the leading industry documents, which provide for the following procedure:

procedure for development of technological processes for welding operations;

procedure for preparation of fixture for assembly of structures;

procedure for preparation of welders;

procedure for preparation of welding equipment;

procedure for preparation of welding materials.

Depending on the main purpose, promising and working technological processes are distinguished.

Promising technological process - includes a sequence of technological operations, breakdown of the structure into separate technological units or elements, sketching of special devices and accessories, calculations of modes of main welding processes, calculations of expected welding stresses and strains, comparative assessment of developed versions of the technology.

After final approval of the technical design and the adopted version of the technology, detailed design design (preparation of design documentation) and development of the working technology (preparation of process documentation) are performed.

The workflow includes the following actions:

clarifications and changes of the process principle associated with the design change at the detailed design stage;

development of Job Instructions indicating all welding mode parameters, welding materials and equipment used;

brief descriptions of the procedures for performing individual welding operations;

requirements to quality of welded structures at separate stages of their manufacture;

Specify methods for checking accuracy and quality control of joints, assemblies and finished design.

Depending on the number of products covered by the process, two types of process have been established:

typical;

single.

The rules for the development of work processes provide for the mandatory use of standard technological processes and standards for technological operations.

Depending on the level of detail, each process can be routing, operational, or operational.

A process operation is part of a process plan that is performed at one work center.

There are the following main steps in developing a typical process plan:

classification of production objects - select groups of objects having common design and technological characteristics and typical representatives of groups;

quantity evaluation of object groups - evaluation of production type (single, serial or mass);

analysis of structures of typical objects according to drawings, specifications, production programs and type of production - develop the main routes of production of structures, including procurement processes;

selection of parts and methods of their manufacture with technical and economic evaluation - evaluation of accuracy of characteristics of manufacturing methods and surface quality, selection of processing method;

selection of technological bases;

selection of production type (welding, casting, pressure treatment, machining);

preparation of a process processing route - determining a sequence of operations and selecting groups of equipment for operations;

development of technological operations;

calculation of accuracy, productivity and cost-effectiveness of standard process variants with selection of the optimal option;

preparation of standard process documentation, its approval with interested services and approval.

Development of technological operations includes:

selection of structure and rational construction of operations;

determining a rational sequence of transitions in an operation;

Selection of equipment for optimal performance and quality

calculation of process equipment load;

selection of process tooling design;

calculation of processing allowances and inter-operation allowances, establishment of initial data for calculation of optimal processing modes and time standards;

definition of category of works and profession of performers.

The enterprise should have computer information and search systems to search for previously developed similar technological processes and individual technological operations. All information is input into the computer in coded form.

During development of technological process, processability of welded articles and structures is analyzed. The quantitative evaluation of processability is based on a system of indicators, which includes:

basic processability indicators set in the technical assignment for structural design;

processability indicators achieved during design development;

level of processability (ratio of achieved indicators to basic ones).

The main indicators of processability are labour intensity and production cost of constructions.

Factors affecting the selection of indicators: product requirements; article type; volume of output; Availability of information necessary for the definition of indicators.

Design requirements determine what type of processability the design should have: production, operational or both, which, in turn, determines the group of processability indicators.

Depending on the type of structure (assembly unit, complex, set or part), those indicators that can characterize the processability of this type of structure are selected from groups.

Knowing the volume of output allows you to choose the indicators that characterize expenses or costs and are most important at a given volume of output.

Before starting work, the welder must inspect the equipment and verify its serviceability, remove dust and dirt from the power sources, as well as comply with safety measures during welding.

Check availability and serviceability of preheating and associated heating device during welding, if necessary, as well as availability of tested instruments for heating temperature monitoring, if necessary.

Check operability of ammeters and voltmeters on sources and equipment during automatic welding.

Check for ammeters on manual arc welding posts. Check the requirements of the production and technical documentation for the type of current used, voltage deviation of the electrical network, connection to independent power sources, flushing of burners and hoses.

Check serviceability of accessories and accessories, as well as compliance of their parameters with upcoming operations. Manipulators and roller stands shall ensure reliable fixation on them and smooth movement of welded parts.

The workshop power engineering service is responsible for the operability and serviceability of welding equipment, devices and instrumentation.

Results of welding equipment, accessories and instrumentation monitoring are entered in the welding work log.

Welding electrodes and fluxes shall be calcined at a temperature of 3003500C for 1-2 hours before being put into production. The welding wire must be checked for contamination on the surface (rust, scale, lubricant traces, etc.) before starting. If necessary, clean it by any technical or chemical method. Welding materials must be stored and transported in conditions that protect the integrity of the electrode coating, the surface of the wire from contamination and mechanical damage, moisture.

Including the following activities:

Ensure that the internal guide channel is correctly selected in the burners. Replaceable guide channel is selected by welding wire diameter;

when welding with stainless wire, the supply channel changes;

correctly select the tip according to the diameter of the welding wire, in case of unacceptable wear, replace the tip;

clean the nozzle from splashes of metal, otherwise the nozzle under the potential of the electrode when in contact with the product may fail. To better remove splashes, the nozzle must be treated with a special paste or spray (aerosol) can be a solution of chalk in water;

start the welding wire through the feed mechanism to the guide channel when the feed mechanism is turned off. Press the pressure rollers, turn on the feed mechanism. The pressing forces of the pinch rollers must be adjusted so that when the wire is forcibly delayed, the feed rollers slip. The wire at the outlet of the tip must not lose its shape from pressing by the supply rollers;

twist the tip selected by welding wire diameter into a plug. Dress a spray-clean nozzle;

select the welding wire feed rate, gas flow rate, voltage and current, depending on the thickness of the welded article and the spatial position during welding;

prepare the workstation for welding, ground the article with return wire (reverse polarity (+) on the burner (-) on the article).

2.8 Selection of mechanical assembly equipment

Grinding and finishing operations are grinding and grinding of welding seams, removal of seam forces, grinding of welded structures, as well as application of protective coatings.

Grinding of welds from slag, grat and scale, grinding of welds and removal of strands, as well as cleaning and finishing of welding products is carried out mechanized by hand electric and pneumatic machines. These machines are also used to grind welded edges and surfaces from rust, scale and contamination.

It is mechanized - manual cars are divided by the form the drive into pneumatic and electric, to destination - on grinding, cleanup, rubilny and milling and on a design - on direct, angular and face.

As mechanical welding equipment for machining of this welding structure, we choose: pneumatic grinding machine IP2014 BTU 221661388; circle grinding software 150x25x3214A of GOST 12401397.

Comprehensive mechanization and automation of production is inconceivable without a system of transporting devices that eliminates or minimizes the use of live labor.

Efficient use of conveying devices is achieved when they correspond to the nature of production, the type of manufactured products, their products, their sizes, weight, etc.

In mass production, the transportation of blanks, parts, assemblies and finished products is carried out mainly with the help of bridge cranes, forklift trucks and self-propelled trolleys. Mechanization of fixation and release of sheet elements when using cranes is provided by using specialized grips with slings.

This structure is transported by means of bridge crane Q = 2.5 t, gripped by slings 2SK GOST 2557382.

Production calculations

4.1 Selection of production type

The difference in the product production program led to the conditional division of production into three types: single, serial and mass.

Single - the production of single non-repeating copies of products or with a small output volume, which is similar to the characteristic of the non-repeating technological cycle in a given production. Single production products - products that are not widely used (prototype machines, heavy presses, etc.)

Serial - periodic technological continuous production of a certain amount of the same product over a long period of calendar time. Production is carried out in batches. Depending on the volume of production, this type of production is divided into small, medium and large-scale.

Mass - technologically and organizationally continuous production of a narrow range of products in large volumes according to unchanged drawings for a long time, when most workplaces perform the same operation.

Of the considered types of production, the production of the "Side side 9334" product according to the annual production volume of 1500 pieces refers to serial production.

Conclusion

In this diploma project, work was carried out on the development of the process of assembling and welding the wiring of the bottom stand of the carbon steel furnace 10.

The project includes a graphic part of two sheets of A1 format. The work consists of several sections reflecting the sequence of development of the manufacturing process of the welded structure.

Sections of the main part characterize the equipment of the welding station of semi-automatic welding in the environment of protective gases, due to their qualities, for example, such as: the ability to relatively easily obtain a high-quality welded joint; high efficiency of welding by this method compared to manual arc welding, gas welding; absence of fluxes and coatings, and accordingly operations to clean the seam from slag; possibility of complete automation of welding process; the arc during welding in protective gases is more concentrated, therefore, the thermal influence zone is minimal; welding is accompanied by minor stresses and strains. Justification for selection of welding arc power supply and welding materials.

The welded wiring design of the bottom stand of the furnace was made with the use of Sv.0G2S welding wire GOST 224670.

In this diploma project, the following equipment was selected for the welded structure "Furnace Bottom Stand Wiring":

feed mechanism KEMPIFastMig MXF 65;

power supply KEMPIFastMig KMS 500.

Detailed process of assembly and welding of the furnace bottom stand wiring with indication of all locksmith, assembly and welding works, equipment, accessories and tools for welding is developed in the section of the process part.

In the section on testing welded joints, the main methods of nondestructive testing are applied: visual measurement, radiographic, hydraulic, ultrasonic inspection, and so on.

The diploma project presents safety techniques for welding production.

The normative and technological material is presented in the form of tables, figures and diagrams.

At the end there is a list of the literature used.

This diploma project can be approved for use in production for the manufacture of wiring of the bottom stand of the furnace.