Side side side 9334

Introduction

Welding is one of the leading processes of metal processing. The great advantages of welding ensured its wide use in the national economy; without it, the production of ships, turbines, boilers, aircraft, bridges, reactors and other structures is now inconceivable. Welding is the process of producing a permanent joint by establishing interatomic bonds between the parts to be welded with their local or general heating, or plastic deformation, or the combined action of both.

Welded joint of metals is characterized by continuity of structures. To obtain a welded joint, intermolecular adhesion between the parts to be welded is necessary, leading to the establishment of an atomic bond in the boundary layer.

If the protected surfaces of the two jointed metal parts are brought together under high pressure so that a common electronic cloud interacting with the ionized atoms of both metal surfaces can occur, a strong welded joint will be obtained. On this principle, cold welding of plastic metals is carried out.

With an increase in temperature at the junction of the parts, the amplitudes of the oscillation of atoms relative to the constant points of their equilibrium state increase, and thereby conditions are created for easier obtaining a bond between the connected parts. The higher the heating temperature, the lower the pressure required to perform welding, and when heated to melting temperatures, the required pressure becomes zero .

Melting welding is carried out by heating the welded edges to the melting temperature without squeezing the welded parts.

All existing welding methods can be divided into two main groups: pressure welding (contact, gas-compression, friction, cold, ultrasonic) and melting welding (gas, termite, electric arc, electric slag, electron beam, laser).

The most common are various methods of melting welding, and the leading place is arc welding, the source of heat at which is an electric arc.

In 1802, the Russian scientist V.V. Petrov (17611834) discovered an electric arc discharge and indicated the possibility of its use for melting metals. With his discovery, Petrov laid the foundation for the development of new branches of technical knowledge, which later received practical application first in electric arc lighting, and then in electric heating, melting and welding of metals. In 1882, a Russian engineer N.N. Benardos (18421904), working on the creation of large batteries, discovered a method for electric arc welding of metals with a non-consumable carbon electrode. He also developed methods of arc welding in protective gas, metal arc cutting, etc.

The arc welding method was further developed in the work of the Russian engineer N.G. Slavyanov (18541897), who proposed in 1888 to weld with a melting metal electrode. Slavyanov's name is associated with the development of the metallurgical foundations of electric arc welding, the creation of the first automatic arc length regulator and the first welding generator. He proposes fluxes that make it possible to obtain high-quality metal of welds.

The inventions of Benardos and Slavyanov were patented and used not only in Russia, but also in all industrialized countries.

The advantage of welded structures is not in doubt at present. The use of welding gives not only metal savings (by 2025% compared to riveting and up to 50% compared to casting), time and labor, reduced costs for equipment of metal structures manufacturing workshops, improved working conditions, but also allows solving a number of complex technical problems for creating fundamentally new structures. For example, only through the use of welding has it become possible to manufacture very economical ball vessels for the chemical industry, unique hydraulic and steam turbines, the manufacture of which uses parts and assemblies of complex shapes, large thicknesses from various alloyed steels; two-layer metals (bimetal), which are low-carbon or low-alloy steel coated with a thin layer of high-alloy steel.

Various types of welding are used in various plants, such as manual arc welding, semi-automatic in the medium of carbon dioxide, argon arc, contact. They provide reliable operation within a given resource, allow to manufacture the product at minimum costs of materials, labor and time.

In the manufacture of designs for manufactured products: dump trucks, buses, a car factory widely uses semi-automatic welding in the environment of carbon dioxide, it provides a fairly reliable insulation of the welding bath when working in factory conditions.

The purpose of this diploma project is to develop the technology of assembly-welding of the product "Side side 9334."

Process Section

2.1 Critical analysis of existing technology

Currently, the Neftekamsk factory of car dump trucks uses the technology of assembling and welding the Side 9334 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 semi-automatic 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.

2.2 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.

Process Section

2.1 Critical analysis of existing technology

Currently, the Neftekamsk factory of car dump trucks uses the technology of assembling and welding the Side 9334 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 semi-automatic 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.

2.2 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.

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