Development of technology for assembly and welding of volume bottom section of tanker with deadweight of 8,300 tons

Contents

A4 Introduction

1. Project Terms of Reference

1.1. Purpose of the article and its technical characteristics

1.2. Requirements for welding material and rolled stock

1.3. Applied materials and weldability analysis

1.4. Calculation of consumption rates of welding materials during welding of vessel and hull structures

2. Process Part

2.1. Analysis of the process of assembly and welding of the product used in the enterprise

2.1.1. Edit Sheet Metal and Profile Rolled Stock

2.1.2. Cleaning and priming

2.1.3. Manufacturing of parts

2.1.4. Gas cutting

2.1.5 Bending of parts

2.1.6. Plasma cutting

2.1.7. Assembly and welding of plane section panel

2.1.8. Welding of idle set to plane section panel

2.1.9. Bottom section assembly and welding sequence

2.2. Improved welding process. Preparation of Job Instructions

2.3. Processability of products

3. Selection of welding equipment and materials

3.1. Arc welding accessories and tool

3.2 Welding equipment used

3.2.1. A2 Multitrac tractor with REN control unit

3.2.2. Kempoweld welding semi-machine

3.2.3. Welding machine ADF-800 for arc welding with melting electrode

3.2.4. Welding transformer TDM

3.3. Materials used

3.3.1. Flux for automatic welding OK Flux 10.

3.3.2. Welding wire for automatic welding

3.3.3. Welding electrodes for RDS

3.3.4. Powder wire for welding in the environment of protective gases OK Tubrod 15 .

3.4. Selection of auxiliary equipment and materials

4. Calculation of welding modes

4.1. Calculation of arc welding mode under flux

4.2. Calculation of semiautomatic welding mode in mixture M

4.3. Calculation of manual arc welding modes

5. Quality control of welds. Understanding Welding Stresses and Strains

5.1. Welding Quality Control

5.2. Defects in welds and joints

5.3. Methods of non-destructive testing of welded joints

5.4. Concept of welding stresses and strains

5.5. Structural and technological methods of welding deformation reduction

5.6. Welding Deformation Prevention Techniques

6. Ecology and Occupational Safety

6.1. Environmental protection

6.2. Welding Safety

6.2.1. Electrical safety of welder

6.2.2. Explosion safety

6.2.3. Protection against burns

6.2.4. Respiratory protection

6.2.5. Fire safety

7 Economic part

7.1. Calculation of technical and economic parameters of the process, assembly and welding of the product

7.2. Calculation of economic efficiency of the selected version of the process of assembly and welding of the product

Conclusion

Literature

Introduction

The growth of oil production in the Caspian region, the development and integration of pipeline oil and gas highways of the Caspian countries increasingly makes us think about the development of marine infrastructure, which in the future will become a reliable link between Caspian exporters. It is the development of offshore oil transport that will make it possible in the future to strengthen the importance of strategic pipeline areas. Understanding this, governments and private companies have already spent a lot of money on the reconstruction of their ports, the construction of terminals, today we are talking about the construction of a modern tanker fleet on the Caspian Sea and who will be the first to own the "palm of the championship," which consists in huge transit dividends and the full load of their pipeline capacity. Therefore, an important direction of diversification of export routes is the growth of the volume of transportation of oil and petroleum products in the Caspian Sea. For these purposes, the states of the Caspian region create their own tanker fleets. The Russian Federation, as a member of this region, also having large oil deposits in the northern part of the sea, also needs to have its own tanker fleet competitive with other states. Another reason for the need for tankers is the small depth of the northern part of the Caspian Sea, which makes it environmentally problematic to build a pipeline.

The high environmental requirements associated with the isolation of the Caspian Sea (lake) require a high class of production of oil vessels and a certain deadweight of the tanker. In this regard, it is necessary to modernize the old technologies for the manufacture of various parts of the ship, the use of new materials for welding methods that increase the strength and other mechanical properties of the product. A tanker with a deadweight of about 8 thousand tons is the optimal option for the Caspian, large vessels of this class are undesirable, since there is a risk of environmental disaster. A tanker of this type can enter any ports of the Caspian Sea states, as well as climb the river and go to the basin of other seas, which allows you to transport oil not only in the Caspian Sea basin, which makes transportation cheaper and there is no need to attract rail transport.

1.2. Requirements for welding material and rolled stock

The welding material coming to the plant shall have accompanying documentation (certificates) certifying its quality in accordance with the requirements for supply.

It is recommended to store welding materials in dry heated rooms, sorted by lots, grades and diameters.

Before the welding materials are put into production, they should be prepared for welding in order to comply with the conditions imposed on the welding materials before their use:

welding wire must be dry, clean (without traces of rust, oil, protective coatings, process lubricant, etc.);

before winding the welding wire in cassettes in case of contamination (traces of rust, oil, process grease) on it, it should be machined (cleaned). Quality control of cleaning for compliance is performed visually;

Labels indicating the grade and diameter of the wire, as well as the melting number, shall be attached to the cassettes.

electrodes used for welding of steel structures must be calcined.

At receipt of a hire on the plant, it has to be examined and checked for compliance to the existing standards or specifications (by certificates), is sorted, marked, difficult on ranges, brands, swimming trunks and thickness. Acceptance shall be carried out by OTC.

2.1.2. Cleaning and priming

Cleaning from scale and rust, followed by priming or passivation, all sheet steel is subjected to before feeding to the tag and cutting of parts. Priming of sheets, parts of which are subjected to hot bending or heat treatment, is not carried out before commissioning. After cleaning and passivation, all sheets are marked with the material mark and melting number, and if necessary, the thickness of the sheet is added to the mark.

2.1.3. Manufacturing of parts.

Layout-Creates a part outline on the surface of the original workpiece or creates reference lines for mating parts during assembly. Part markings are performed when mechanical cutting is provided. During marking, the contours of the parts are applied to the rolled stock in full size, taking into account the processing allowances. Manual sketching is performed.

Places the simplest sheet metal parts with straight edges, without internal or edge cuts. The layout designer performs all necessary constructions on the sheet. Marking is fixed on metal by core. Profile rolled stock parts are placed and marked in sketches. It is placed on specially equipped tables, consisting of a number of metal goats. For marking, the profile fits on these goats. The process of marking half-beam steel consists of marking the length of the part.

6.1. Environmental protection.

In accordance with the Constitution of the Russian Federation, they take measures for the protection and rational use of land and its subsoil, water resources, the growing and animal world, to preserve the purity of air and water, ensure the reproduction of natural wealth and improve the environment. These activities are grouped into sections: protection and use of water resources, protection of the air basin, protection and rational use of land, protection and rational use of mineral resources.

The protection and use of water resources provide for the construction of facilities for the extraction of water from reservoirs, the treatment of wastewater, the creation of recycled water supply systems in order to reduce irretrievable water losses.

In welding production, many enterprises have a system of recycled water supply. Water used for cooling welding equipment is repeatedly used after its natural cooling.

Protection of the air pool provides for measures to neutralize substances harmful to humans and the environment, emitted with waste gases: the construction of treatment plants in the form of wet and dry dust collectors for chemical and electrical cleaning of gases, for the capture of valuable substances, waste disposal. For example, liquefied carbon dioxide is produced from combustion effluents for welding and other purposes.

The protection and rational use of land includes measures aimed at reducing the withdrawal of land from agricultural circulation, protecting them from erosion and other destructive processes, and reclamation.

As for production noise, vibration, exposure to electric and magnetic fields, the activity of the enterprise should not violate the regulatory conditions of work of other enterprises and organizations, as well as worsen the living conditions of the population .

Noise generated by welding equipment shall be minimal.

6.2. Welding Safety

Welding refers to work with increased danger, which entails a number of requirements, the fulfillment of which is mandatory. The main hazards in welding operations are:

danger of electric shock during welding operations by arc welding;

burns of the skin and visual organs with radiated electric arc energy and splashes of molten metal;

negative impact on the human body of gases, vapors and dust emitted during welding;

mechanical injuries during assembly works and sub-preparation of parts for welding;

explosion hazard of combustible gas cylinders and acetylene generators;

fire hazard during all fire operations;

radiation damage at radiation method of welded joints control;

during installation work, there is a danger associated with working at height.

Therefore, only persons who have reached the age of 18 and have undergone special training and medical examination are allowed for welding.

6.2.1. Electrical safety of welder

By electric safety of the welder is meant a set of measures preventing electric shock. The peculiarities of the human body are such that an electric current with a force of 0.05 A or more at a frequency of 50 Hz is dangerous and can cause death.

The degree of danger of electric current depends on many factors and in each particular case can vary significantly. But in any case, it is believed that for a person the current passing through the body should not exceed 0.1 A. Electric shock occurs when touching current-carrying parts of equipment or wiring under voltage. The amount of voltage a person may be under depends on the amount of idling voltage of the welding arc power supply. The power supply voltage of the normal welding arc usually reaches 90 V, and the compressed arc - 200 V.

The very first and most effective means of protection against electric shock is the grounding of equipment and welded parts and the provision of reliable insulation.

For the purpose of electrical safety, the idling voltage of welding equipment is limited to the following values:

- DC generators - up to 80 A;

- transformers - up to 90 A.

Each welding apparatus is provided with a separate grounding wire connected directly to the grounding line. Power supplies are grounded before they are connected to the power network, and their removal should be carried out only after disconnection from the power network. In addition, protective fences, self-locking, individual protective equipment are used. It is forbidden to use process equipment, structures of electrical installations and grounding loop as back welding wire.

Electric welding equipment shall be regularly (at least once a month) checked for:

- absence of closure to the housing;

- integrity of grounding wire;

- absence of bare current-carrying parts;

- no short circuit between high and low voltage windings;

- serviceability of interlocks.

During external welding operations the equipment shall be reliably protected from rain and snow. Outdoor welding during bad weather is prohibited.

Welding in winter conditions and during rain is carried out under a special shelter or other shelter, ensuring that the welder's workplace is dry.

6.2.2. Explosion safety

During gas welding operations, explosions are possible during improper transportation, storage and use of compressed gas cylinders. During flammable processing processes, acetylene generators may explode from a flame back impact if the water shutter does not work. Explosions are caused by the presence of oil on the connector of the oxygen bottle or on the reduction gear box.

Gas cylinders shall be protected from sunlight and other heat sources during operation.

The room in which the cylinders are stored shall be located at a distance of not less than 25 m from the place where the flammable works are carried out. In one room, cylinders with only homogeneous gases can be stored, empty cylinders are stored separately from full ones.

During transportation, the cylinders are laid with valves in one side and transported in a horizontal position with the obligatory use of gaskets. Cylinders are placed only in one row. In the body of the car there should be no traces of oil, fat, as well as oiled objects.

During loading and unloading operations, it is impossible to remove cylinders from the car with caps down. It is not allowed to carry cylinders on your hands. In cases of detection of leaks of the bottle, it must be taken to a safe place and, if possible, carefully discharged from the non-gas .

Special care should be taken in handling oxygen bottles. Many substances burn in the oxygen stream, including metals, and flammable liquids (oils, fats, oil, etc.) burn with explosion. Therefore, persons in contact with oxygen cylinders should work in clean clothes, there should be no traces of oils and fats on their hands and tools.

6.2.3. Protection against burns

Burns caused by a welding arc are dangerous, especially for the eyes. The brightness of the light beams of the welding arc significantly exceeds the norm permissible for the human eye.

Ultraviolet rays, which are one of the components of the light flux of the arc, even with a short action for several seconds, cause an eye disease called electroophthalmia. The disease is accompanied by acute pain, incision in the eyes, lacrimation, eyelid cramps.

With significant damage to the eyes by the luminous flux of the welding arc, you can even be blinded. Prolonged exposure of the skin to arch light causes its burns. In addition, sparks scattered during welding can cause burns. Therefore, all participants in the welding process must use protective devices.

In electric welding operations, the main such device is a protective mask, the viewing hole of which is equipped with a light filter that deters infrared and ultraviolet rays and reduces the brightness of the light flux of the arc.

Gas welders use protective glasses that reduce the brightness of light. Selection of light filter is performed depending on arc power and welding method.

To protect against skin burns, tarpaulin clothing and sleeves are used. Do not perform welding operations with rolled hoses and open gate. Workwear and shoes of the welder should ensure optimal heat exchange of the body when working with physical loads, effectively protect against splashes of molten metal and dangerous weather conditions, have optimal weight characteristics, do not hamper freedom of movement, meet aesthetic requirements.

To protect the legs, leather (in summer) or felt (in winter) shoes should be used that protect against heat radiation, cold, sparks, splashes of molten metal.

Hands are protected by sleeves from thermal radiation, contact with surfaces heated above 45 ° C, from low temperatures and welding splashes.

Partitions, portable screens, etc. are used to protect those around them from light flux and sparks of molten metal.

3.2.4. Respiratory protection

During welding operations, harmful gases and aerosols appear, the amount and composition of which depends on the welding method, welded metals and welding materials, and the welding mode. Manganese aerosols are especially dangerous to health, which can cause prolonged and persistent damage to the nervous system, up to paralysis. Many oxides, falling on the mucous membrane of the respiratory organs, destroy it, cause allergic phenomena, bleeding and even bronchial asthma. Chromium oxides are especially dangerous.

When non-ferrous metals are welded into the environment, harmful gaseous compounds are released, the poisoning of which can adversely affect health. Therefore, protective masks and filter respiratory devices should be used to protect the breathing organs of the welder and the hand worker. In order to ensure that the respiratory device does not interfere with the operation, it is necessary to use lightweight structures of the Snowball type 201 and 301 - models that meet the following requirements:

respiratory agents simultaneously protect the respiratory organs from very toxic both solid and gas components of the welding aerosol;

respiratory devices are compatible with other means of protecting the face, eyes, head (shield, glasses, helmet);

respiratory devices provide a minimal load on the respiratory system, soft facial tissues and the head.

In addition to personal protective equipment, the welder's workplace is equipped with plenum ventilation, which ensures the optimal composition of the ambient air.

3.2.5. Fire safety

Welding operations can cause fire if elementary fire protection requirements are not met.

The cause of the fire may be sparks and drops of molten metal, negligent handling of the welding torch fire, the presence of combustible liquids and gases at the workplace, entanglement in the place of fire work. Fire hazards should especially be taken into account on construction and installation sites and during repair works, in places not suitable for welding, etc. Therefore, fire protection measures should be strictly observed at welding sites, correctly organizing the workplace. If welding operations are carried out at a height, then the protection of the workplace and cleaning from burned materials should be taken into account.

Construction materials, floorings, structures etc. placed within the specified boundaries shall be protected against sparks by metal screen, non-combustible material cover or other available means. In extreme cases, materials can be poured with water. Doors to spaces adjacent to welding shall be permanently closed, process hatches shall be closed with fire-resistant materials. Welding works, which are carried out in places of passages or driveways, shall be fenced with hanging of warning posters. All process equipment, where welding works are provided, shall be pre-prepared and brought to the state satisfying fire protection measures. Welder's workplace is equipped with primary fire protection equipment.

After completion of welding works, the contractor must carefully inspect the place of their execution, eliminate possible sources of fire. If welding work was carried out on fuel supply routes, in cable structures, warehouses with combustible materials and other fire hazardous places, then within 3 hours after work it is necessary to organize monitoring of this place.