Seek the construction scheme of steel structure workshop foundation

steel structure manufacturing and construction technology

scope of application: it is suitable for the manufacturing process of building steel structure, including process selection, lofting, marking, cutting, straightening, forming, edge processing, tube ball processing, hole making, friction surface processing, end processing, component assembly, circular tube component processing and steel component pre-assembly

1. 1.

1.1.2 raw materials entering the factory must have the ex-factory quality certificate of the manufacturer, and should be sampled, delivered, inspected and accepted on the spot under the witness of Party A and the supervisor according to the contract requirements and relevant current standards, and the inspection records should be made. And provide the inspection report to Party A and the supervisor.

1.1.3 in the process of processing, if raw materials are found to be defective, they must be studied and handled by inspectors and competent technicians.

1.1.4 Material substitution shall be made by the manufacturing unit in advance with an application form (technical verification sheet) attached with the material certificate, and it can be substituted only after being submitted to Party A and the supervisor for approval and confirmed by the design unit.

1.1.5 it is forbidden to use covered electrode with peeling coating or rusty welding core, flux caked with moisture or burnt, and rusty welding wire. The surface of the stud used for stud welding shall not have defects such as cracks, streaks, dents and burrs that affect the use.

1.1.6 welding materials should be managed centrally, and a special warehouse should be established, which should be dry and well ventilated.

1.1.7 bolts should be stored in a dry and ventilated room. The warehousing acceptance of high-strength bolts should be carried out according to the requirements of the current national standard "Code for Design, Construction and Acceptance of High-strength Bolt Connections in Steel Structures" JGJ82. It is forbidden to use high-strength bolts that are corroded, contaminated, damp, bruised and mixed.

1.1.8 the coating shall meet the design requirements and be stored in a special warehouse. expired, deteriorated and caked coatings shall not be used.

2 main tools

1.2.1 main tools

long-term tools for steel structure production.

3 Operating conditions

1.3.1 Complete the detailed construction drawing and sign it by the original designer.

1.3.2 all kinds of technical preparations such as construction organization design, construction scheme and work instruction are ready.

1.3.3 various process qualification tests, process performance tests and material procurement plans have been completed.

1.3.4 main materials have entered the factory.

1.3.5 all kinds of mechanical equipment have passed the debugging and acceptance.

1.3.6 all production workers have received pre-construction training and obtained corresponding qualification certificates.

4 operation technology

1.4.1 process flow

1.4.2 operation technology

1 lofting and marking

1) Be familiar with the construction drawing, and if you find any questions, you should contact the relevant technical department to solve them.

2) Prepare materials for making templates and sample rods. Generally, thin iron sheets and small flat steel can be used.

3) The steel rule required for lofting must be checked and rechecked by the metrological department, and it can only be used if it is qualified.

4) Before marking, you must know the materials and specifications of raw materials and check the quality of raw materials. Parts with different specifications and materials shall be marked separately. And according to the principle of first big and then small, the materials are numbered in turn.

5) Paint shall be used to indicate the processing number, component number and specification on the sample rod of the sample plate, and various processing symbols such as hole diameter, working line and bending line shall be marked.

6) Shrinkage (including welding shrinkage on site) and machining allowance required for cutting and milling should be reserved for lofting and marking:

Milling allowance: generally, 3-4 mm is added to each side after cutting, and 4-5 mm is added to each side after gas cutting.

cutting allowance: automatic gas cutting slit width is 3mm, and manual gas cutting slit width is 4mm.

the welding shrinkage is given by the process according to the structural characteristics of the component.

7) When marking materials, the main stressed components and components that need to be bent should be taken in the direction specified in the process, and there should be no sample punching points and scars on the outside of the bent parts.

8)No. material should be conducive to cutting and ensure the quality of parts.

9) The remaining materials after this marking should be marked with the remaining materials, including the number, specification, material and batch number of the furnace, so as to facilitate the reuse of the remaining materials.

steel structure

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2 Cutting

The steel after blanking and marking must be cut according to its required shape and size.

1) The following points should be paid attention to when cutting:

(1) When many parts are arranged on a steel plate and there are several intersecting cutting lines, reasonable cutting procedures should be arranged in advance before cutting.

(2) The bending deformation of materials after shearing must be corrected; The shearing surface is rough or has burrs, so it must be polished and smooth.

(3) In the process of shearing, the metal near the incision is squeezed and bent due to shearing force, and the interface position between important structural parts and welding seams must be milled, planed or ground with grinding wheel.

2) During the construction of sawing machinery, the following construction points should be paid attention to:

(1) Section steel should be straightened before sawing.

(2) For single-piece sawed components, the marking line shall be drawn first, and then the line shall be sawed. Components processed in batches can be processed by installing positioning baffles in advance.

(3) For important components with high machining accuracy, appropriate machining allowance should be reserved for end face finish milling after sawing.

(4) When sawing, attention should be paid to the control of the verticality of the cutting section.

3) During gas cutting operation, the following key points should be paid attention to:

(1) Before gas cutting, all equipment and tools of the whole gas cutting system must be checked to ensure normal operation and safety.

(2) Correct process parameters should be selected during gas cutting. When cutting, the shape of oxygen jet (wind line) should be adjusted to achieve and maintain a clear outline, a long wind line and high shooting power.

(3) Before gas cutting, the dirt, oil stain, floating rust and other sundries on the steel surface should be removed, and a certain space should be left below to facilitate the blowing of slag.

(4) during gas cutting, backfire must be prevented.

(5) In order to prevent gas cutting deformation, the operation should start from the short side; Small pieces should be cut first, then large pieces; The more complicated ones should be cut first, and the simpler ones should be cut later.

3 correction and forming

1) correction

(1) cold correction of finished products is generally carried out by mechanical forces such as flange leveler, straightener, hydraulic press and press.

(2) flame correction, there are three heating methods: point heating, linear heating and triangular heating.

① The heating temperature for thermal correction of low carbon steel and common low alloy steel is generally 6 ~ 9℃, while 8 ~ 9℃ is the ideal temperature for thermoplastic deformation, but it is not allowed to exceed 9℃.

(2) Medium carbon steel will crack due to deformation, so it is generally not necessary to correct it by flame.

③ Ordinary low alloy steel should be cooled slowly after heating correction.

④ Process flow

2) Forming

(1) Hot working: Generally, the temperature of low carbon steel is 1 ~ 11℃, and the end temperature of hot working should not be lower than 7℃. The heating temperature is 5 ~ 55℃. Steel is brittle, so it is forbidden to hammer and bend, otherwise it will easily break the steel.

(2) cold working: steel is processed and manufactured at room temperature, mostly by using mechanical equipment and special tools.

4 edge processing (including end milling)

1) Common edge processing methods mainly include: edge shoveling, edge planing, edge milling, carbon arc gouging, gas cutting and beveling machine processing.

2) For gas-cut parts, when the affected zone needs to be eliminated for edge processing, the minimum machining allowance is 2.mm.

3) The depth of the machined edge should ensure that the surface defects can be removed, but it should not be less than 2.mm, and there should be no damage and cracks on the machined surface. During grinding, the grinding marks should follow the edge.

4) After the edge of carbon structural steel parts is cut by hand, the surface should be cleaned, and there should be no unevenness exceeding 1. mm..

5) The supporting edge of the end of the component requires planing and jacking, and the accuracy of the section of the end of the component is high. No matter how it is cut and made of steel, it must be planed or milled.

6) There are special requirements or regulations in the construction drawing that the welded edges need to be planed, and the cut edges of general plates or sections do not need to be planed.

7) After mechanical automatic cutting and air arc cutting, the flatness of the cutting surface should not exceed 1.mm. The free edge of the main stress-bearing member needs the machining allowance of planing or milling after gas cutting, and each side should be at least 2mm, and there should be no defects such as burrs.

8) More than 75% of the butting contact surface after column end milling should be close to each other. Check with a .3mm feeler gauge, and the plugging area should not be greater than 25%, and the edge clearance should not be greater than .5 mm..

9) The choice of milling mouth and milling amount should be decided according to the workpiece material and machining requirements, and reasonable selection is the guarantee of machining quality.

1) The end processing of components shall be carried out after the rectification is qualified.

11) Necessary measures should be taken according to the form of components to ensure that the milled end is perpendicular to the axis.

5 hole making

1) The methods of making holes for high-strength bolts (large hexagon head bolts, torsional shear type bolts, etc.) and self-tapping screws for semi-circular head rivets include drilling, milling, punching, reaming or countersinking.

2) drilling is preferred for component drilling, and punching is allowed when it is proved that the quality, thickness and aperture of some materials will not cause brittleness after punching.

punching is allowed for all ordinary structural steels with a thickness of less than 5mm, and punching is allowed for minor structures with a thickness of less than 12mm .. On the punching hole, welding (groove shape) shall not be carried out subsequently, unless it is proved that the material still retains considerable toughness after punching, welding construction can be carried out. In general, when the hole to be punched is drilled again, the punching hole must be 3mm smaller than the specified diameter.

3) before drilling, one is to grind the drill bit, and the other is to select the chip allowance reasonably.

4) The bolt hole should be cylindrical, perpendicular to the surface of the steel where it is located, with an inclination of less than 1/2. There should be no burr, crack, bell mouth or concave-convex marks around the hole, and the cutting should be clean.

5) The diameter of the bolt hole made by refining or reaming is equal to the diameter of the bolt rod. After reaming with drilling or assembly, the hole should have the accuracy of H12, and the surface roughness Ra of the hole wall is less than or equal to 12.5μ m..

6 processing of friction surface

1) The processing of friction surface of high-strength bolt connection can be carried out by sandblasting, shot blasting and grinding with a grinder. (Note: The grinding direction of the grinder should be perpendicular to the stress direction of the component, and the grinding range should not be less than 4 times the diameter of the bolt. )

2) The treated friction surface should be protected from oil pollution and damage.

3) The manufacturer and the installation unit shall conduct the anti-slip coefficient test with steel structure manufacturing batches respectively. The manufacturing batch can be divided into two batches according to the division (sub-part) of the project, and the quantity of each batch is 2t, and those less than 2t can be regarded as a batch. When two or more surface treatment processes are selected, each treatment process shall be inspected separately, with three groups of specimens in each batch.

4) The test specimens used for the anti-slip coefficient test shall be processed by the manufacturer, and the test specimens and the steel structure members they represent shall be made of the same material, made in the same batch, treated with the same friction surface technology and have the same surface state, and connected by high-strength bolts of the same batch and performance grade, and stored under the same environmental conditions.

5) the thickness of the steel plate of the specimen shall be determined according to the thickness of the representative plate in steel structure engineering. The surface of the specimen shall be smooth and free of oil stain, and the edges of holes and plates shall be free of flash and burr.

6) The manufacturer shall conduct the anti-slip coefficient test while manufacturing the steel structure, and issue a report. The test report shall specify the test method and results.

7) According to the requirements of the current national standard "Code for Design, Construction and Acceptance of High-strength Bolted Connections in Steel Structures" or the provisions of design documents, members with the same materials and treatment methods for reinspection of anti-slip coefficient shall be made and handed over at the same time.

7 tube ball processing

1) Rod manufacturing process: purchasing steel tube → inspecting material, specification and surface quality (anti-corrosion treatment) → blanking and beveling → assembling and spot welding with cone head or sealing plate → welding → inspection → anti-corrosion pretreatment → anti-corrosion treatment.

2) manufacturing process of bolt ball: blanking steel bar (or ingot) for pressure processing or round steel for mechanical processing → forging blank → normalizing treatment → processing and locating threaded hole (M2) and its surface → processing each threaded hole and plane → punching processing work number and ball number → anti-corrosion pretreatment → anti-corrosion treatment.

3) manufacturing process of cone head and sealing plate: blanking finished steel → forging blank with tire mold → normalizing treatment → machining.

4) Manufacturing process of welded ball joint grid structure: purchasing steel pipes → checking materials, specifications and surface quality → lofting → blanking → hollow ball manufacturing → assembly → anti-corrosion treatment.

5) Manufacturing process of welded hollow ball: blanking (with copying cutter) → pressing (heating) molding → machine tool or automatic gas cutting groove → welding → NDT inspection of weld → anticorrosion treatment → packaging.

8 assembly

1) Before assembly, the staff must be familiar with the component construction drawing and relevant technical requirements, and check the quality of the parts to be assembled according to the requirements of the construction drawing.

2) Because the size of raw materials is not enough, or the parts that need to be spliced according to technical requirements, they must be spliced before assembly.

3) The following regulations must be observed when assembling with tire molds:

(1) The selected site must be flat and have sufficient strength.

(2) When arranging and assembling the tire mold, the pre-placed welding shrinkage and other machining allowances must be considered according to the characteristics of its steel structure members.

(3) After assembling the first batch of components, the quality inspection department must conduct a comprehensive inspection. After passing the inspection, the assembly can be continued.

(4) The components must be assembled in strict accordance with the process regulations during the assembly process. When there are hidden welds, they must be welded first and covered only after passing the inspection. When complicated assembly parts are difficult to weld, the method of welding while assembling can also be used to complete the assembly work.

(5) In order to reduce the deformation and assembly sequence, the method of assembling parts first and then assembling components can be adopted.

4) The selection of assembly methods for steel structure members must be based on the structural characteristics and technical requirements of the members, combined with the processing capacity and mechanical equipment of the manufacturer, and the methods that can effectively control the assembly quality and have high production efficiency should be selected.

5) assembly of typical structures

(1) construction technology of welding H-beam

technological process

blanking → assembly → welding → correction → secondary blanking → drilling → assembling and welding other parts → correction and grinding

(2) processing technology of box-section members

(3) processing technology of rigid cross column

.

2) Selection principle of pre-assembled assembly parts: as far as possible, select representative composite members with complex main stress frames and joint connection structures, and the component tolerance is close to the limit.

3) Pre-assembly shall be carried out on a solid and stable platform jig. The flatness of its supporting point:

A ≤ 3 ~ 1m2 tolerance ≤ 2mm

A ≤ 1 ~ 5m2 tolerance < 3mm

(1) In pre-assembly, all components should be controlled according to the construction drawing, and the barycentric lines of each member should meet at the center of the node completely.