Development of process of compensator assembly-welding

Contents

Contents

Introduction

Weld Structure Description

Base Metal Selection

Selection and justification of welding method

Selection and justification of welding materials

Calculation of welding modes

Selection of welding equipment

Selection of assembly equipment

Selection of vehicles

Selection and justification of equipment for manufacture of individual parts of welded structure

Assembly and Welding Process Rationing

Welding Quality Control

Site Safety

Occupational Safety Guidelines for Industrial Enterprises

Electrical safety

Requirements for special. clothing and ventilation

Fire safety

13 Organization of welding area

Conclusion

List of used sources.36 -

TASK

On the course project

module: PM 02 MDK 02.02 Process development and product design

Topic: Develop compensator assembly and welding process

Initial data for the course project:

1. Compensator detail

Content of the course project:

Introduction

1 Welded Structure Description

2 Process section

3 Design section

4 Project Reporting Material

4.1 Explanatory note ___ sheets of A4 format

4.2 List of graphic material

4.2.1 General view of welded structure

4.2.2 Process map of assembly and welding

4.2.3 Specification

Conclusion

Introduction

The development of welding structures has a vivid history.

In 1882, the talented Russian inventor N. N. Benardos first proposed a method for connecting and separating metals directly by the action of electric current using a coal arc. This method of welding with a coal arc bears his name.

In 1888-1890 mining engineer N. G. Slavyanov proposed a method for electrical welding of metals with a metal electrode.

Arc welding of metals was widely developed and of great national economic importance after the Great October Socialist Revolution.

In the 30s, intensive use of welding began instead of riveting in structures, which ensured metal savings on 25... 30%, increased labor productivity, freed the worker from the heavy labor of a hammer. The new technology has become not only recommended, but also mandatory in a number of building structures.

Since the second half of the 30s, welding has received new widespread use in various branches of mechanical engineering. During these years, several welded railway bridges were built in the USSR.

Since the 40s, as a result of the activities of the Institute of Electric Welding of the Academy of Sciences of the Ukrainian SSR and, first of all, its founder E.O. Paton, as well as a number of other organizations, the successful use of automatic flux welding in the industry begins, which played an outstanding role during the Great Patriotic War in creating weapons, and later in all sectors of the national economy.

The Institute of Electric Welding named after E.O. Paton, headed for 35 years by academician of the USSR Academy of Sciences, President of the Academy of Sciences of the Ukrainian SSR B.E. Paton, is a coordination and scientific center implementing a scientific and technical policy on welding issues in the country. He has a large number of advanced scientific laboratories, design bureaus, as well as production enterprises that implement scientific developments of laboratories in metal.

The following features were observed in the development of welding in the USSR: in 19241925. Welding processes were carried out manually by electrodes without coating or with thin ionizing coatings. Since 19351939, based on the use of thick-coated electrodes, electrode rods made of alloyed steels and other alloys, welding has been widely introduced in all industries. 1939 is characterized by the beginning of the introduction of automatic and semi-automatic welding under a flux layer, developed under the leadership of G.O. Paton (18701953) at the institute of electric welding he led. Since 1948, arc welding methods in inert protective gases have been commercially used: manual non-consumable electrode, semi-automatic and automatic non-consumable and melting electrodes.

The remarkable achievements of the USSR in the development of advanced welding methods are the creation of welding processes in the environment of carbon dioxide and inert gases; contact welding of rails by continuous melting, gas pipelines by "North" installations; electroslag, semi-automatic welding with powder electrode; plasma and micro - plasma welding; explosion welding; diffusion and high-frequency welding; vibration surfacing; industrial method of production of welded sheet structures and many other improved methods - brought our homeland to an advanced place in the world.

Weld Structure Description

Compensators are ideal shock absorbing and compensating elements of thermal and mechanical changes of the pipeline system. The compensator is installed in the turbine pipeline to connect individual parts of the pipes, in case of sharp temperature fluctuations it contributes to free elongation or compression. Compensator undergoes hydraulic tests.

Compensator consists of 4 parts:

The lug - consists of a pipe profile, with Ø20x12 sizes

Polugofra-consists of sheet metal, with Ø800x115x2 sizes

The feedwell - consists of sheet metal, with Ø540x4x2 sizes

The flange - consists of sheet metal, with Ø660x540, S=16 sizes

Purpose of compensators application:

to compensate for thermal expansion of pipelines;

to prevent destruction of pipes during deformation of pipelines;

To align misalignment in piping systems

for connection of pressure and suction pipelines to units (pumps, turbines, compressors, engines, etc.);

for reduction of vibration loads and sealing of pipelines.

The compensator is subject to the following requirements:

sufficient strength and flexibility;

resistance to pressure changes and heat resistance;

resistance to aggressive substances;

maintaining tightness and strength during vibrations and oscillations;

Selection and justification of welding method

The method of welding is largely determined not only by the quality and labor intensity of the production, but by the whole process. The selection of the welding method begins with the determination of a number of technically acceptable options for each connection, then the type of equipment is selected and indicative processes of assembly and welding are compiled with increased rationing for each option, the total labor intensity and economic efficiency of each method are calculated, and after comparison, a final decision is made in favor of any option.

The main methods of welding parts:

Manual arc welding with a melting coated electrode is carried out using a welding power source and welding electrodes. The electrode is fed into the welding zone and moved along the joint by the welder himself. Both AC (transformer) and DC (rectifier) can be used. The welding electrode is a metal rod with a coating applied to it.

Semi-automatic welding in protective gases. As an electrode, a metal wire of a certain grade is used, to which current is supplied through the current-carrying mouthpiece. An electric arc melts the wire, and to ensure a constant arc length, the wire is supplied automatically by the wire feed mechanism. To protect against the atmosphere, protective gases (argon, helium, carbon dioxide and their mixtures) are used, supplied from a welding torch together with an electrode wire. In the absence of the possibility of semi-automatic welding in the environment of protective gases, self-protective wire (powder) is also used. It should be noted that carbon dioxide is an active gas - at high temperatures, it dissociates with the release of oxygen. The released oxygen oxidizes the metal. In this regard, deoxidizers (such as manganese and silicon) have to be introduced into the welding wire.

Semi-automatic arc welding under flux - welding with an electric arc burning between the end of the welding wire and the welded metal under the flux layer. Artificial silicates having a weakly acidic character are used as fluxes in welding. The flux base is double or triple silicate of manganese oxide, calcium oxide, magnesium oxide, aluminum, etc. As an additive that reduces melting point and viscosity, melting spar is used.

In this course design, semi-automatic welding in protective gases will be used, since it has a number of advantages: high quality welded joints on a variety of metals and alloys of various thicknesses; possibility of welding in different spatial positions; possibility of visual observation of seam formation; no backfilling, flux cleaning and slag removal; High performance and ease of mechanization and automation low cost when using active protective gases.

Normalization of assembly and welding process.

005. Transportation

1.Transport assembled parts and welding materials to the assembly and welding area.

010. Metalwork

1. Grind edges of welded parts from layers of dirt, oil, rust by width of 10 mm on both sides of the seam.

015. Assembly and Welding

1. Install, reconcile and secure part, pos. 2

2. Install and reconcile make pos. 3 on the part, pos. 2

3. Grab the part pos. 3 on the part, pos. 2 minimum number of tacks 2, Lpr = 5 mm.

4. Weld the assembly unit in the lower position with annular seam, LMw = 1696mm

5. Install and reconcile part pos. 4. per assembly unit.

6. Grab the parts pos. 4 to assembly unit, minimum number of tacks 2, L pr = 5 mm.

7. Weld the assembly unit in the lower position with a ring seam.

L seam = 1696mm

8. Remove assembly 1

9. Turn over 180 °, install, remove and attach assembly unit. 1.

10. Install and reconcile assembly unit 2 to assembly unit 1.

11. Attach assembly unit 2 to assembly unit 1

minimum number of tacks 2, Lpr = 5 mm.

12. Weld the assembly unit in the lower position with a ring seam.

LMw = 2513mm

13. Install and reconcile part pos. 1 for assembly unit 1.

14. Grab the part pos. 1 to assembly unit 1, minimum number of tacks 2, Lpr = 5 mm.

15. Weld the assembly unit in the lower position with annular seam, LMw = 63mm

020. Cleaning

1. Clean the welds and the near-seam zone from splashes and molten metal.

025. Control

1. Check the quality of the seam by external inspection for the absence of visible defects, as well as from the specified dimensions. Check geometric dimensions specified in PRZ. Check the number of welds.

030. Transport

1. Remove the assembled structure from the accessory in a mechanized way.

Welding Quality Control

The quality control of welding works begins even before the welder has begun welding the product. The quality of the base metal, welding materials, billets received for welding, the state of welding equipment and the quality of assembly, as well as the qualification of welders are checked. Inspection of procurement prior to receipt of procurement. Cleanliness of metal surface, overall dimensions of billets, quality of edge preparation, angles of bevel edges are checked for assembly.

All these activities are called pre-inspection.

In the process of welding, the appearance of the seam, its geometric dimensions are checked, and the process is monitored. These operations constitute monitoring. The last check step is to check the welding quality of the finished product. For this purpose, the following types of control are carried out: External inspection and measurement of welded joints, density testing, transmission by X-rays or gamma rays. Ultrasonic control, magnetic control methods, luminescent control method, metallographic control method, mechanical tests.

The quality of the base metal shall comply with the requirements of the certificate sent by the supplying plants together with the metal batch. In the absence of a certificate, the metal is put into production only after a thorough inspection, it is necessary to perform an external inspection, a test for weldability, and establish the mechanical properties and chemical composition of the metal. Preliminary inspection of the metal to detect defects is necessary and mandatory, since it should prevent the use of poor-quality metal for welding products.

Quality control of welded wire. The most important is to check the chemical composition of the wire, for which 0.5% of the bays, but at least two, are taken from each batch.

Quality control of fluxes. Flux is checked for homogeneity in appearance, its chemical composition, grain size and humidity are determined.

In the assembled assembly, the gaps between the edges of the welded parts are controlled, the absence or small value of which leads to the failure of the root of the seam, and the large one to burn and increase the labor intensity of the welding process. Process execution control. Before starting welding, the welder is familiar with the process codes, which indicate the sequence of operations, the diameter and grade of the electrodes used, the welding modes and the required dimensions of the welds. Sutures are examined with the naked eye or magnifying glass is used with an increase in Yur along their entire length and necessarily on two sides. The well-made seam has a smooth transition to the base metal, without strains and undercuts, as well as a uniform width and height over the entire length. In some cases, during external inspection, standards are used that evaluate the quality of the welds of the product. In this course design, external inspection and measurements of welded joints are used, which are the main stage of quality control, the following types of equipment are used to perform these measures: measuring line 11000mm, rod-cylinder, roulette, set of templates for measuring the seam leg

Site Safety

12.1. Labour Safety and Sanitation Framework.

Labour protection is a set of technical and organized measures aimed at creating safe and healthy working conditions for workers. Labor protection - first of all provides for the prevention of industrial injuries. The main material basis for improving conditions are new production methods, new equipment, integrated mechanization and automation of production.

Persons who have reached the age of 18 years are allowed for welding. Working welders are given overalls, protective caps and masks. In case of heavy and harmful work, the welder receives special food. Workplaces shall be equipped with various types of fences, safety devices and accessories

12.2. Electrical safety

Electric shock occurs when a person contacts current-carrying parts, to prevent possible electric shock during electric welding work, it is necessary to comply with the basic rules.

The equipment housing and equipment to which the electrical current is supplied must be reliably grounded.

All electrical wires coming from the distributed panels and to the workplace shall be securely insulated and protected from mechanical damage.

It is forbidden to use the contour for fixing the steel structure of buildings, as well as pipes of the water and heating system.

When performing welding work inside closed vessels, wooden shields, rubber mats, gloves, halos should be used for

responsible targets inside vessels, as well as in damp rooms are used

electric current is not more than 1 2V, and in raw rooms not more than 36V.

Electrical equipment shall be installed, repaired and monitored by electricians.

Welders are strictly forbidden to correct power electrical workshops.

12.3. Requirements for special. clothing and ventilation.

Welding and cutting works at machine-building plants are carried out, as a rule, inside production premises. Work in other places is allowed at existing enterprises in accordance with the rules of safety and industrial sanitation in industry. During welding, a significant amount of aerosol is released, consisting mainly of iron oxides, manganese, silicon dioxide and secondary compounds, carbon monoxide is formed during welding in carbon dioxide. C02 is 1.5 times heavier than air, it accumulates in cramped rooms and closed vessels, which can lead to a shortage of oxygen for breathing the welder, to remove excess emissions from the places of welding and supply of clean air, ventilation is used, which can be general and local. In this case, it is advisable to use general ventilation. It shall provide air exchange for one kilogram of molten metal in the following volume:

during welding of carbon and low carbon steels in C02 - 3000 m3

In winter, plenum ventilation should suppress heated air in the room. In case of poisoning, the victim must be taken to fresh air, released from shy clothes, given peace before the doctor arrives. When stopping breathing, artificial breathing should be used.

Special clothing (trousers, jackets, overalls, sleeves) and special shoes are used to protect the worker's body from thermal, mechanical and other impacts, which must correspond to the nature of the work performed and meteorological conditions at the workplace.

Overwear and overwear must be issued in accordance with the standards for individual industries in accordance with standard industry standards for the free issuance of overwear and overwear.

To protect against contact with wet, cold land, snow, as well as with cold metal during external work, welders must be provided with bedding, knuckles and armrest made of fire-resistant materials with an elastic interlayer.

12.4. Fire safety.

For the purposes of fire safety, welder's workplaces in the welding area are enclosed with screens (shields) made of non-combustible materials (sheet steel, asbestos cloth, tarpaulin). Permanent workplaces, as well as protective fences, are painted in light tones (blue, gray, yellow). Welding work near fuels, lubricants, wood and easily flammable materials is strictly prohibited.

To prevent causes of fires, observe the following:

It is not possible to store flammable or flammable materials in a work room or work area.

Wooden flooring shall be protected from ignition.

Each welding station must have a fire extinguisher, a tank or bucket of water, as well as a box of sand.

After welding, check the work area and the area where the welding was performed.

Welding Section Organization

Rational placement in the space of the designed production process and all the main elements of production necessary for the implementation of this process requires the development of plan drawings and sections of the designed workshop. To do this, first of all, you need to establish the composition of the latter.

Regardless of any type of welding industry, the assembly and welding shops, when fully assembled, may include the following compartments and rooms.

Production departments. The procurement department includes production areas: metal straightening and marking, gas-flame treatment (cutting), electrothermal cutting, machine processing, pipe, forge-boiler or stamping (press), locksmith-mechanical and metal cleaning. Assembly and welding compartment, usually divided into assembly and general assembly, with production areas of assembly, welding, surfacing, brazing, riveting, heat treatment, machining, testing of finished products and correction of defects, application of surface coatings and finishing of products. Areas of machining, coating and finishing of products are not included in the designed assembly and welding workshop, if the structures welded in it are to be transferred to the mechanical assembly workshop for installation of mechanisms, final assembly, finishing and production of plant products.

Support offices. Shop metal warehouse with unloading site and metal preparation area, intermediate warehouse of parts and semi-finished products with their sorting and picking area, inter-operation folding areas and places, store of finished products of the workshop with control and packing compartments and loading area. Storage rooms of electrodes and fluxes, cylinders with combustible and protective gases, tools, accessories, spare parts and auxiliary materials. Workshops: manufacture of templates, repair, electromechanical, etc. Compartments: electric machine, acetylene, compressor.

Administrative-office and household premises. Shop office, wardrobe, latrines, washrooms, showers, buffet, room for rest and eating, first-aid post.

Depending on the size of the assembly and welding shop and the peculiarities of the production processes located in it, some of the above mentioned compartments, areas and premises may be absent or combined with others; it is also possible to allocate some departments and sites to independent workshops.

When designing both the entire plant and its individual workshops, it is necessary to strive for the straightforward implementation of all production links between individual workshops, to their most convenient mutual arrangement and to prevent the return movement of materials and products.

For the purpose of the most rational layout of individual links of production processes outside and inside the workshop, it is necessary to clarify the production connection between the designed assembly and welding workshop and all its suppliers and consumers at the plant. At the same time, the location of the designed workshop in relation to other workshops, warehouses and other plant-wide facilities should be the closer, the greater its production connection with each of them. Meeting these requirements results in the lowest transport costs and loss of time for the movement of goods between workshops and establishes the main prerequisites for the design of in-house cargo flows.

Conclusion

In the course design, an optimal version of the compensator manufacturing process was developed.

For this compensator, low-alloy steel 09G2C made according to GOST 1928173 was selected, which operates at a temperature of 70 to + 425 ° C and is welded without restrictions. Semi-automatic welding in protective gases was chosen for welding of 09G2C steel. As an electrode, a metal wire of the SvavlG2S grade is used. To protect the seam from the atmosphere, carbon dioxide supplied from the welding torch together with the electrode wire is used .

Based on the welding method you selected, welding modes were calculated for each weld.

Parameters of welding modes in carbon dioxide gas are diameter of binding wire, welding current value, electrode wire feed rate, arc voltage, welding speed, carbon dioxide flow rate, electrode discharge.

Based on the calculations of welding modes, the Rikon semiautomat PDG302 is selected, which is designed for welding with a melting electrode wire on a direct current of parts from ordinary and stainless steels up to 10 mm thick in the environment of protective gases.

For the manufacture of the compensator, special assembly devices, transport devices and equipment for the manufacture of individual parts of the welded structure have been selected.

As a result of the process of assembly and welding of the compensator, optimal versions of assembly and welding were selected, which allows to obtain better seams, increase productivity and reduce manual labor of workers.