The steel structure planning project has extremely high strength, and better construction effect can be achieved when the plant floor is higher or the span is larger. However, many actual constructors in our country know little about the steel structure project, so they can't really grasp the welding key of the steel structure planning project, which has a certain impact on the final quality of the steel structure project. Therefore, in order to improve the construction quality of steel structure planning and construction, it is necessary to strictly control and control the welding part of the steel structure project to ensure the quality of the steel structure planning project and promote the continuous updating of the construction profession and construction skills.
1. Control of process factors
1.1 Control of pre welding preparation of steel structure planning project
Preparation before welding of steel structure planning mainly refers to groove preparation, welding equipment and cleaning of welding area.
(1) Preparation of groove: the processing of welding groove directly affects the quality of welding operation, so it should be operated strictly according to the steel structure planning process; Attention shall also be paid to the fact that the raw materials, specifications and types of the arc tab groove of the steel structure planning shall be the same as those of the base metal.
(2) Welding device: the device quality not only affects the dimensions of the steel structure planning components, but also has a certain impact on the weld formation. When welding the device, it is necessary to consider whether it is easy to weld after the device. If the device affects the normal welding of individual steel structure planning welds, it is necessary to weld this weld before installing other parts. All welding materials of the device shall match with the base metal, and the spot welding height shall not exceed 2/3 of the planned weld height of the steel structure.
(3) Cleaning of planned welding area of steel structure: oil stain, rust, dust, etc. on both sides of the joint shall be completely removed to prevent blowholes and cracks in the planned weld of steel structure.
1.2 Control of welding sequence
Selecting a reasonable welding sequence for steel structure planning can reduce the deformation degree of components and prevent the occurrence of cracks. Therefore, when selecting the welding sequence for steel structure planning, the welding seam should be in a relatively free shortening state as far as possible. The welding seam with a large shortening amount should be welded first, and then the welding seam with a small shortening amount, so as to ensure that the planned welding seam of steel structure has a large shortening freedom during welding and a small planned residual stress of steel structure occurs.
1.3 Control of welding process specification parameters
The welding process specification parameters of steel structure planning mainly include welding specification parameters, preheating temperature, post heat and hydrogen elimination treatment, post weld heat treatment, etc. The welding specification parameters are clearly specified in the process, and the steel structure planning workers should strictly follow the process. The selection of welding current and arc voltage for steel structure planning shall be emphasized. The current is too small and the arc is unstable, which is easy to cause slag inclusion, incomplete penetration and other defects; If the current is too large, undercut, air hole, welding and other defects are easy to occur, and they are added together by splashing. Long arc means high arc voltage, unstable arc burning, spatter addition, small penetration, and external air intrusion, which constitute the defects of air hole incomplete penetration.
The steel structure planning project is widely used in industry and public construction, and the welding process is the key process in the steel structure processing and manufacturing. Strengthening the quality control of the welding process can not only improve the quality of steel structure planning products, but also have a very important effect on the quality of the entire steel structure planning project. Based on this, this paper mainly discusses the key points of welding quality control in steel structure planning project.
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