Although steel structure is widely used in various fields by virtue of its own advantages, it is precisely because of the increasing use that people begin to care about the quality of products. The key to the same products that will not have problems when they are used is quality. However, the main key to the quality of products is processing, so it should be especially when processing. Pay attention to ensure the quality of products can be recognized by everyone. When processing products, the following control points should be paid attention to.
I. Drawing deepening
1. The detailed design drawings shall improve the structure and node structure of the steel structure according to the design drawings. This paper analyzes the welding deformation and the stress deformation of the structure, and puts forward the treatment measures for the pre deformation of the structure.
2. Specify the number, positioning ruler, weight, material and other information of the component. It should be able to reflect the overall three-dimensional relationship of the project, the main control coordinates and other macro information, so as to facilitate the measurement and control during installation.
3. Segment according to the site lifting requirements, and fully consider the installation deviation, weld shrinkage deformation and other factors, and try to weld the positions that need to be welded on site in the processing plant, such as curtain wall embedded parts, operation platform.
II. Raw material control
1. Steel: the quality certificate or inspection report issued by the steel plant shall be checked in detail, and the chemical composition, mechanical properties and other quality requirements shall meet the current national standards.
Inspect and check one by one according to the steel quality certificate and size specification table, and check the surface quality, thickness and local flatness of the steel. There shall be no lamination, slag inclusion and other defects at the end or fracture of the steel.
2. Welding materials: the welding materials used need to match the steel used in the project. Due to the quality differences of different production batches, spot check shall be carried out in batches as required.
Electrodes and fluxes shall be kept properly and shall not be damped, otherwise not only the process performance of operation will be affected, but also the physical and chemical properties of joints will be adversely affected. The welding test shall be conducted again after the welding materials are placed for too long or damped.
III. Blanking and hole making control
1. Before cutting, the cleanliness, flatness, cutting size, section roughness, perpendicularity, notch depth and groove angle of the steel structure surface shall meet the requirements; the surface of the assembly and welding place shall be treated.
2. Setting out: for the assembly of all components and parts, and the assembly of component pre assembled parts, professional setting out workers are required to carry out accurate setting out on the processing surface and the assembly large template. After setting out, it must be inspected by the inspector to ensure that the geometric dimension and angle of the component processing are correct.
The drilling template, connecting plate and joint plate after drilling correspond to the datum line on the body; the hole eccentricity, hole distance offset, hole distance, roundness and verticality, hole wall and hole edge surface quality shall be strictly controlled. In order to ensure the accuracy and quality of drilling, the setting out workers must set out and draw out the datum axis and the middle of the hole when using the die drilling.
IV. Assembly control
1. The strength, rigidity, levelness and relevant tooling and fixture of the assembly platform and moulding bed; the size of the detail and special mould; the material, number, size, processing accuracy, quantity, connection and surface treatment of the welding place of the parts; the datum plane, datum line, cross middle line, assembly position line of the parts; the assembly position, direction, angle and concentricity of the parts , perpendicularity, camber, angle of groove, blunt edge, clearance, sealing of backing plate and dislocation of joint; assembly sequence and method, additional welding shrinkage and machining allowance; size, length, spacing, position and surface quality of positioning welding.
2. Component assembly: component assembly refers to the spot welding and positioning fixation before submerged arc welding. Before assembly, small materials shall be corrected. The setting out personnel shall draw out the middle line and positioning line. The spot welding fixation shall be carried out after the inspection is qualified, and the formal welding shall be delivered after the inspection.
V. Correction
1. Correction: Correction work runs through the whole process of steel structure manufacture, from blanking to blanking, submerged arc welding, assembly manual welding and so on, must be corrected to ensure that the size, quality and shape of components meet the requirements of specifications, and strictly control bending and distortion.
2. Friction surface treatment: the end of the connecting friction surface of the component shall be milled by the milling machine, and the friction surface shall be treated by the shot blasting machine to produce floating rust under natural conditions. At the same time, the same materials and processing methods shall be used to make test pieces for friction surface processing, and the friction coefficient test shall be carried out to ensure that the friction coefficient meets the specified requirements.
3. Component surface treatment: the processed parts, components and components shall be edge processed according to the regulations, burr, welding slag, welding spatter, dirt, etc. shall be removed, and surface inspection shall be carried out. After the components are finished and the surface is cleaned, the surface shall be derusted with shot blasting machine.
VI. finished product inspection
Steel stamp marks such as drawing No., component No., axis line, zero line, 1m elevation line and their directions and positions. Whether the total length, section size, curvature, twist, camber, inclination of both ends, diagonal of plane, groove welded on site, hole spacing and position size of installation hole are qualified, appearance quality of component and chamfer of cutting free edge, etc.
With the continuous development of society, steel structure has been gradually applied to our daily use, so when processing products, we need to ask our construction personnel and construction personnel to bear in mind the above processing quality points, so as to ensure the processing quality. During the construction, we should also follow the specified operation steps, and then ensure the construction. The quality of the process, and then make the product have double guarantee.