Assembly-welding technology of BDA-4 deaerator housing

Contents

Introduction

Section 1 Process Part

1.1. Product Description

1.2.1 Operating conditions of the article

1.3. Characteristic of the base metal

1.3.1 Weldability

1.3.2 Welded joints

1.4. Selecting a Welding Method

1.5. Selecting Welding Materials

1.5.1. Gas selection

1.5.2. Welding Wire Selection

1.5.3. Welding Flux Selection

1.6. Selection of equipment for assembly-welding of deaerator BDA tank

1.6.1. Selection of welding equipment

1.7. Development of manufacturing process of BDA- deaerator tank

1.8. Selecting Weld Type, Dimensions, and Edge Preparation

1.8.1. Calculation of welding modes

1.9. Quality Control

Section 2 Design Part

2.1. Technical requirements for tooling

2.2. Selection of process bases and procurement basing

2.3. Description of tooling, and its operation, for shell welding

2.4. Calculation of fluxing cushion cylinder pneumo

2.5. Shop Site Plan

Section 3 Calculation and Planning of Main Technical and Economic Parameters of Welded Structure Production

3.1Organising the planning of production works in the welding area

3.2Processing Efficiency Improvement Directions

3.3 Procedure for organization of repair and maintenance of welding production

3.4Creation and prevention of safe working conditions in the welding area

3.5Compute and plan the cost of the welded structure based on the standards of process modes, labor and material costs

3.5.1Compute the cost of material and support

3.5.2Process power cost calculation

3.5.3 Calculation of basic wages of production workers

3.5.4 Calculation of additional wages and social contributions

3.5.5 Calculation of depreciation deductions for operation of equipment and mechanization facilities

3.5.6 Calculation and planning of main technical and economic parameters of welded structure production

3.5.7 Planning the cost of the welded structure unit

3.5.8 Calculation of the selling price of the enterprise for the welded structure

3.5.9Planning of main parameters of production and implementation of welded structure

3.5.10 Annual Production Planning

3.5.11 Planning revenue from sales and cost of annual output

3.5.12 Profit and profitability planning

Section 4 Safety of Assembly-Welding Process

4.1. Comparative characteristics of welding processes according to standard and new designed technology

4.2. Brief characteristics of welding types

4.2.1. Flux Welding

4.2.2. Mechanized welding in CO

4.3. Proposals to improve process and equipment safety

4.3.1Optimization of air environment parameters

4.3.2 Calculation of local exhaust ventilation

4.4Optimization of production lighting

4.4.1 Calculation of artificial lighting

4.5Protection against radiation

4.5.1 Noise Protection and Insulation

4.6Assuring safe operation of cylinders

4.7. Ensuring electrical safety. General requirements for welding equipment

4.8Fire safety

4.9Adjustment of the environmental situation

Conclusion

List of sources used

Appendix A Roadmap

Appendix B Assembly-Welding Routines

Appendix B Specification

Introduction

In this diploma project it is necessary to develop the technology of assembly and welding of BDA4 deaerator tank. The deaerator is used to remove corrosive gases (oxygen and free carbon dioxide) from the make-up water of heat supply systems in boiler houses of all types.

Since the product for design was selected as finished, the diploma project does not address product design issues. However, when developing the technology of manufacturing and selecting welding equipment, it is necessary to take into account the processability of manufacturing the structure, namely the convenience and simplicity of manufacturing, which will provide a reduction in the cost of manufacturing the container and reliability during operation.

It is also important to select the correct sequence of actions (process plan). The welding process is usually accompanied by auxiliary processes, and therefore auxiliary equipment (welding equipment), which is also of great importance in the process.

In this diploma project, the technology of manufacturing and welding of the container was developed, and welding equipment was also selected. By rationally selecting the welding method and welding materials, the manufacturing cost of the structure can be significantly reduced compared to similar manufacturing techniques.

Operating conditions of the article

During operation, the deaerator tank is subjected to static load on the walls of the tank body due to excess fluid pressure.

Operating temperature of the tank is 104.2 ° С.

Based on this, it can be concluded that the most harmful effect on the product has internal pressure, and corrosion damage from an aggressive working environment. The product can be attributed to responsible structures, must comply with DNAOP 0.001.07-94, Rules for safe operation of pressure vessels. Our task is to ensure absolute tightness of the welded article, operation safety during the design service life, namely 20 years, the possibility of getting rid of overpressure during operation of the deaerator tank, as well as to provide the possibility of technical inspection, cleaning, repair, operational control of metal and joints. Low-carbon steel 09G2S as per GOST 552176 is selected for manufacture of the article.

Welded joints

Standard manufacturing technology included: welding using mechanized welding in a CO2 environment,. The main disadvantages of this process are:

- Low welding performance due to lower welding speed;

- High cost due to use of expensive welding materials, more welders, and used equipment;

- More harmful process from the point of view of occupational safety in the application of p/a welding, compared to automatic welding under flux.

Selecting a Welding Method

To select a welding method, you must find out which methods to select. It is rational to choose from typical ways. The main methods that are widely used in the production of welded structures include: manual arc welding (E), mechanized and automated welding in C02 (UP), welding with a melting electrode in inert gases (IP), automatic welding under flux (AF), electroshlag welding (W), gas welding (G), laser welding (arc-arc welding) (Arc welding)

It is also necessary to take into account the factors that determine the method of welding: the chemical composition of the material, thickness, transportability of the welded product, position during welding, availability, connection configuration and length of joints, design accuracy, product release program, type of production, cost, etc.

Selection of equipment for assembly, welding of BDA-4 deaerator tank

Welding equipment shall meet all the requirements of the process, as well as meet the requirements of safety precautions in the manufacture of the product. The equipment shall comply with safety standards, be reliable in operation and easy to maintain, provide the required welding modes and control of welding parameters during operation.

Welding current sources used for article welding shall meet the following requirements:

provision of high dynamic properties (time of transition from short circuit to operating mode is not more than 0.01 second );

The power of the welding current source shall be sufficient for welding the article;

Welding current sources have additional requirements for resistance to external climatic and mechanical factors:

possibility of sources operation in the temperature range from plus 40 0С to minus 40 0С;

possibility of operation at relative ambient humidity up to 80% (at temperature plus 20 ° C );

resistance to environmental mechanical factors

Installations for welding in the environment of protective gases shall ensure preliminary gas supply before arc excitation and delay of gas supply disconnection after welding completion.

Quality Control

To ensure the quality of the capacity fabrication works, we will develop a quality assurance scheme that will make it possible to obtain constant quality of the finished products and reduce the amount of scrap. This can significantly reduce manufacturing costs as well as labor costs.

The quality assurance scheme is based on the operational control of the production process, and is a clear algorithm for actions when a non-conformance is detected in the process.

The essence of the scheme is that if it is observed, it is not possible to switch from one operation to another, if there is any discrepancy in the process of the previous operation.

Quality control requirements:

Quality control shall be performed during all works during manufacture of structural elements in accordance with DNAOP 0.001.07-94, Rules for arrangement and safe operation of pressure vessels;

In appearance, welds shall meet the following requirements:

- have a smooth surface or a uniform flaky surface (without strains, burns, constrictions and interruptions) and do not have a sharp transition to the base metal. In structures that accept dynamic loads, corner welds must be made with a smooth transition to the base metal;

- built-in metal must be dense along the whole length of the seam, have no cracks;

- undercuts of the base metal are not allowed;

The following defects of weld joints are allowed, which you are physical control methods:

- do not break through the section of the seams in the joints accessible to welding on both sides with a depth of up to 5% of the thickness, but not more than 1 mm with a length of no break of not more than 30 mm, the distance between non-break of not less than 300 mm, and the total length of the section of no break of not more than 200 mm per 1 m of the seam;

- individual slag inclusions or pores or clusters of pores with a diameter of not more than 10% of the thickness of the welded, but not more than 2 mm;

- slag inclusions or pores are located along the seam if their total length does not exceed 100mm;

Cracks of all kinds and directions in welds are not allowed. The section of the seam with the crack must be drilled (hole diameter 5-8 mm) along the edges of the crack plus 15 mm on each side from time to time - countersink the hole.

Defects of welded joints shall be corrected in the following way: seams with defects exceeding the permissible ones, removed by the length of the defective place plus 15 mm on each side and re-welded; undercuts of the main metal exceeding the permissible ones are cleaned and welded with subsequent grinding, which will ensure smooth transition from the built-up metal to the main metal.

Corrected defective places or parts thereof shall be checked again.

Incoming control

Welding materials, which must be accompanied by quality certificates, shall be subject to input inspection. Do not use welding materials whose grades are unknown. Incoming inspection shall be performed in accordance with GOST 24297 - 87 "Incoming inspection of products. Basic provisions. "

Operational control

• Operational control shall be carried out at all stages of tank fabrication. At the same time, it is necessary to monitor compliance with all technological modes and operations, which are given in this document.

Acceptance control

• Acceptance control includes external inspection and measurement of tank elements. External inspection must be carried out both after tacking and after welding.

• Measuring equipment used in the manufacture of this structure shall be subjected to routine calibration.

Section 2 Design Part

2.1. Technical requirements for tooling

The tooling must ensure the immobility of the parts during the manufacture of the product, their exact positioning (deviations within the tolerance are allowed) should be convenient in operation, there should be no difficulties in installing and removing the blanks. It is necessary to ensure free access to the equipment of working personnel. It is required to operate in the required temperature range of 20 °... + 30 ° C at relative air humidity up to 80%.

Since the production of the reservoir is a mass process and manufacturing, it will be advantageous to construct a device for manufacturing the product that meets the following requirements.

- The design shall ensure stable quality of the finished product.

- The tooling design shall ensure easy installation and removal of the product, accessibility to the welding site.

- The design shall be technologically and economically feasible.

- Measures for occupational safety and environmental protection are calculated.

In this case, the snap-in design is based on:

• Study of drawings and specifications (TS) for welding structure;

• Product Production Program Analysis;

• Feasibility study of the best possible manufacturing option.

The production program of the release does not determine the complexity of the device. It is therefore advantageous to provide mechanisms for mechanizing and automating the container welding article.

Thus, the choice of fixture depends on the design of the product, the material and the configuration of the part, as well as on the given production capacity.

In multi-stage production, it is advisable to use fast-acting mechanical devices, as this leads to increased profitability in the manufacture of the product. A person must only control mechanized devices, loading and shipping of the product, installation and removal.

2.2. Selection of process bases and procurement basing

To secure the workpieces in the tooling, it is necessary that for each object a force → part → stop scheme is performed. Moreover, in such a way as to deprive the detail of all degrees of freedom. Therefore, for our assembly we accept such diagrams (assembly drawing):

Production of the article consists of three parts. This is the manufacture of shells, the assembly of shells with bottoms, and welding in one piece.

In this way, the master bases are selected for each operation. Thus, for the manufacture of shells (longitudinal seam), the connection of shells with the bottoms, the main measuring size will be the end surface of the welding edges their coaxiality during the connection, and the auxiliary - the side surface of the shell.

For the manufacture of the container, the main measuring dimension is the overall dimension along the length, as well as in the previous case, the end surface of the welded edges their coaxiality during connection.