Exchange rate project: "Boiler for copper 50 tons"

Contents

Introduction

1. Characteristics and analysis of weldability

2. Requirements of Design Fabrication Specification

3. Analysis of existing manufacturing process

welded structure

4 Selection of the design process diagram

and automation of assembly-welding of the structure

5 Justification and selection of process elements

6 Process rationing

7 Safety, Health, Fire and Safety Measures

safety and ecology

List of literature

Introduction

In the field of welding production in the manufacture of metallurgical equipment, the labor costs for welding do not exceed 30%. A large volume is occupied by procurement, assembly, auxiliary and transport operations.

Obviously, only mechanization of welding works cannot have a significant effect of increasing labor productivity. Therefore, the need for complex mechanization and automation covering the entire production process, including not only the main (procurement, assembly, welding, finishing), but also auxiliary (transport, control) operations, is an urgent problem of modern production.

Improving the production of welded structures requires not only the presence of mechanisms capable of carrying out all the necessary operations of the technological process, but also their rational layout. At the same time, the requirements for both mechanisms and their layout are determined by the nature of production. So, for large-scale and mass production, specialized equipment is needed, on the basis of which in-line and automatic target lines are created.

A ladle with a capacity of 5.5 tons for molten copper was made in workshop No. 79 of Azovmash OJSC. This company is one of the basic enterprises of the country for the production of metallurgical equipment. The ladle steel structure resource can reach 50 years, but despite this, it can be said that such metallurgical equipment is in worn out condition both on the territory of Ukraine and on the territory of the countries of the former USSR. Based on this, we can say that the market for metallurgical equipment is quite promising and in the coming decade it is possible to increase the demand for such products.

Requirements of Design Fabrication Specification

OST 24.940.0182 Welded steel structures. General technical requirements.

This industry standard applies to steel welded structures of metallurgical engineering.

2.1. General provisions

- Structures shall be manufactured in accordance with the requirements of this standard for technical documentation developed in accordance with the requirements of the ESKD and AETD standards and approved in accordance with the established procedure.

-.The accuracy of dimensions and geometry shall be in accordance with this standard (Tables 1-8).

2.2 Requirements for design and execution of welds and joints.

- When designing welded structures in order to assign minimum section joints, they should be calculated in accordance with the design norms of SNiP 11-c steel structures.

3-72 and design standards for angular joints of welded joints of metal structures of lifting and transportation machines as per RTM 24.090.6080.

- Types of welded joints and their assembly accuracy tolerances shall comply with the following standards: GOST 526480, GOST 1153475, GOST 1153375, GOST 871379,

GOST 1477176, GOST 2351879, GOST 1477679, GOST 1603780, GOST 1609880, GOST 1587879, GOST 1516478.

- In order to reduce the weight of the built-up metal and internal stresses after welding, the design should limit the V-shaped and asymmetric X-shaped edge preparation in welded joints. V-cut should be used in case of impossibility of double-sided seam and at small metal thicknesses (less than 12 mm).

- All welds shall be subjected to external inspection and measurement. Depending on the operating conditions of the structures or its individual elements, the designer additionally assigns appropriate types of tests to determine the mechanical properties, structure and chemical composition of the weld metal, as well as corrosion resistance. Such control shall be specified in the drawings or in other technical documentation for this design attached thereto.

- The surface of butt joints of welded structures operating under alternating or impact loads shall be mechanically cleaned flush with the base metal or the boundaries of the joints shall be fused with a tungsten electrode in a protective medium, as shall be indicated on the drawings.

- After thermal treatment of welded structures, external inspection of all seams should be performed and, if necessary, check for detection of internal cracks and non-densities of seams, as well as depending on the complexity of the structure according to the purpose of the technologist, its dimensions should be checked.

- Types of defects of welds, norms of unacceptable values of the most widely occurring defects, methods of their control and correction are given in section 7.

Heat treatment requirements

- Thermal treatment of welded structures or stabilization of residual stresses by other methods (ultrasonic, low-frequency vibration processing and static loading method) in each case shall be assigned by the designer and indicated in the drawings. The method of stress stabilization is established by technological services.

- Rigid welded structures, including closed seams, excluding their free shrinkage and made of steels containing carbon more than 0.22 and elements equivalent to carbon, above 0.6, at a thickness of more than 25 mm, must be subjected to heat treatment or another method of stress stabilization.

- Heat treatment (stress stabilization) after welding is performed by welded structures subject to asymmetric machining, which causes unacceptable curvatures. The need to assign such heat treatment is established by process services.

- The heat treatment mode shall be assigned according to the relevant instruction or according to a specially designed process. The furnaces shall ensure uniformity of heating of structures, as well as their protection from deformations under the influence of their own mass.

Requirements for parts. General provisions

- Accuracy of parts manufacturing depending on complexity and dimensions of welded steel structures shall be assigned uniquely or one or two squares higher than accuracy of finished mechanically unprocessed structure.

- For all dimensions placed on the working drawings in accordance with GOST 2.30768, limit deviations are assigned according to ST CMEA 14475, ST CMEA 17775 and OST 24.001.2778.

- Dimensions of parts of welded steel structures, if necessary, shall be installed taking into account shrinkage from welds in accordance with RTM 24.010.2374, and dimensions of parts to be machined as part of finished steel structure, in addition, shall include allowance for mechanical treatment as per RTM 24.940.1075.

- Tolerances for the corresponding dimensions of parts forming the total size during their sequential processing should be assigned so that the sum of their deviations of the same name does not exceed the same deviations by the total size.

- It is allowed not to develop drawings on parts (sheets, plates, blocks, flanges, etc.) made of rolled metal at right angles or in circumference without their subsequent machining, including those subjected to machining as part of the finished welded structure. The necessary data should be specified in the schedules and assembly drawings. Limit deviations in the dimensions of such parts shall be assigned within the limits (cutting accuracy) given in GOST 1479280 for oxygen and plasma cutting of steels up to 100 mm thick, for oxygen machine cutting of steels up to 100 mm thick, for cutting of steels with guillotine or scissors and for cutting shaped rolled stock, respectively, in Tables 17,19,20 of this standard.

- Surface quality of unprocessed edges of parts shall comply with the data given in GOST 1479280.

- For piping parts made of carbon steel, limit size deviations, roundness tolerances, difference and corrugations shall comply with GOST 1738077.

- Tolerances of the shape of parts made of sheet are given in Tables 9 and 10 of this standard.

-. Requirements for bent parts, stamping, forging and castings.

- Roundness (ovality) tolerance of rolling shells shall correspond to the data given in Table 11 of this standard.

- Tolerances of checked components of parts after bending from profile and rolled stock shall comply with this standard.

- On parts after bending, nicks and dents of depth more than 2 mm are not allowed in the amount of more than 5 pieces per 1 meter of length.

- Flatness tolerances (not fit to the plate) of a ring bent from an angle, channel or I-beam shall be in accordance with Table 12 of this standard.

- Tolerances for dimensions of bottom diameters shall be as specified in Table 13 of this standard.

- Tolerances of the shape and quality of the bottom surface after stamping and machining shall be in accordance with this standard.

- Forging and stamping made of carbonaceous and alloyed steels shall meet the requirements of the relevant standards.

- Surfaces of steel forgings not to be machined shall be cleaned of scale and burrs.

- Steel castings shall comply with the standards set out in Annex 1.

- On treated surfaces of cast parts in weakly loaded casting places, separate small shells are allowed, if their total area does not exceed 3 areas on which they are located, with a size of not more than 3 mm each and a depth of up to 10 wall thickness, but not more than 3 mm.

- Correction of casting defects (shells, fistula, etc.) on treated and unprocessed surfaces by brewing is allowed according to RTM 24.041.0174.

Material Requirements

- Materials used for steel welded structures shall be designated by the designing organization and shall meet the requirements of the relevant standards and specifications.

- It is allowed without making changes to the design documentation, in agreement with the designer, to replace the grades of carbon steel of ordinary quality with similar (if economically feasible) ones that have at least acceptable values ​ ​ of the corresponding indicators according to RTM 24.911.0374.

Basic Materials

- The main types of rolled stock used in metallurgical engineering shall comply with the standards given in Appendix 2.

- The chemical composition and mechanical properties of steels used for the manufacture of welded structures shall comply with the standards given in Appendix 3.

- Quality of sheet metal surface shall meet the requirements of GOST 1463779 and GOST 1652370.

Welding materials

- Selection of electrodes for manual arc welding of carbon, low-alloyed and alloyed structural and alloyed heat-resistant steels shall be made according to GOST 946775, for welding of high-alloyed steels - according to GOST 1005275, for welding of low-alloyed high-strength steels according to Specification 14446875, for manual arc surfacing of surface layers with special properties - according to GOST 1005175. At other equivalent values, it is preferable to use electrodes with higher deposition coefficients. Transportation, storage and testing (if necessary) of electrodes for arc welding and surfacing shall be carried out in accordance with the requirements given in GOST 946675.

- Tungsten rods with emission activators shall be used as non-consumable metal electrodes (when welding in the environment of protective gases, plasma welding and cutting): lanthanized - according to PSTS 45CM115063; iterated, VI grade diameter 810 mm - as per BC 0.21.099 TS, diameter 2-8 mm - as per BC 0.021.0127. TU.

- Wire for welding of steel structures shall comply with GOST 2246-70.

- Manufacture, testing and storage of powder wire, which is changed for welding of steel structures from low-alloy steel, shall comply with specification 1444871 and specification 1444971 of activated wire (APAN2 grade) shall comply with specification 144106780.

- Flux for welding of steel structures shall comply with GOST 908781 and ChMTU 1101770 (flux AN17M for welding of low alloyed high-strength steels).

- Carbon dioxide used for welding of carbon steel and low alloy steel shall comply with GOST 805076.

- Argon used for welding of steel structures shall comply with GOST 1015779.

- Acetylene used for oxygen cutting of steels shall comply with GOST 545775, and natural gas shall be at a calorific value not lower than 8000kcal/m3.

- The oxygen used for cutting shall comply with the first and second classes as per GOST 558378 and GOST 633178.

- Removed electrodes after their long-term storage before use shall be punctured according to the data specified in the electrode pass port, and powder wire according to the specification for its manufacture and before use shall be subjected to repeated technological tests.

- Before welding to remove moisture, the flux should be calcined at a temperature of 350 0С for 2-3 hours, transported from the workshop to the workshop in a closed container.

Design Assembly Requirements

- Parts must meet drawing and process requirements prior to assembly. Mating surfaces of assembled parts shall be cleaned from oil, dirt, rust, ice, etc.

- assembly of structures for welding shall be carried out according to working drawings in accordance with the developed process.

- weldment assembly method shall be selected depending on tolerances specified in assembly drawings. The accuracy of the assembled structures can be unambiguous (simplest structures) or should be higher than welded structures (excluding machining) by at least one quota. The assembly accuracy achieved by various methods is shown in Table 24 of this standard.

- Assembly of structures shall be carried out on assembly slabs, stands, in conductors, in special readjustable prefabricated devices (GOST 1793472, GOST 18047-72) providing the required arrangement of parts by means of clamping them by mechanisms and application of tacks in places of seams location.

- During the development of the process for the assembly of structures, shrinkage from welds according to RTM 24.010.2374 (i.e. indicate dimensions larger than the drawing by the shrinkage value), as well as allowance for mechanical treatment of finished structures as per

RTM 24.940.1075.

- When assembling shells into the housing, as well as bottoms with the housing, the longitudinal seams of adjacent shells and bottoms must be shifted in relation to each other by three times the maximum thickness of the joined elements, but not less than 100 mm between the axes of the joints.

- Gaps in welded joints and displacement of edges relative to each other shall comply with the requirements given in Clause 1.3.2.

- When assembling for point or seam contact welding, the clearance between contacting surfaces at points or seam locations shall not exceed 0.50.8 mm. When welding stamped and other rigid parts, the clearance shall not exceed 0.20.3 mm. Assembly is carried out using special clamps or in protective devices. Tack on point machines is allowed.

- Tacks made in case of necessity outside the seams location shall be removed after performance of their purpose, and places of accommodation shall be cleaned.

- The dimensions of the leg of the tacks shall be 0.7 of the size of the leg of the seam, but not more than 6 mm (so that during subsequent welding the tacks are blocked by the seam). Tacks with a spool of more than 6 mm are specified by the process .

- The length of each tack shall be 4-5 times the thickness of the tack elements, but not more than 100 mm.

The distance between the grips shall be 3040 times the thickness of the gripping element, but not more than 500 mm. Extreme grips must be located at a distance of not more than 200 mm from the edge of the sheet.

- Requirements for quality of tacks shall be the same as for welds.

-. Tacks and welding of process strips shall be performed by workers who have a certificate for the right to perform welding operations.

- Assembly of items for electroslag welding shall be performed according to

OST 24.942.0182.

- The assembled structure before welding shall be checked by the production foreman and accepted by the workshop technical control.

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