Prefabricated Steel Structure Building Welding Defects and Prevention

Prefabricated Steel structures (steel structure prefabricated workshops,  warehouses) are often welded in the manufacturing process. The welding quality not only affects the appearance quality, installation accuracy, and increase production costs, but also affects the connection strength and safety of steel structures. The performance and the use of functions, etc., Therefore, it is necessary to analyze and sort the welding defects. This article describes the quality requirements and the causes of common defects, and proposes preventive measures, hoping to improve the welding quality of prefabricated steel structures. 

Quality requirements for welded pores in prefabricated steel structure (steel structure prefabricated workshops,  warehouses) engineering, causes and preventive measures

No surface porosity is allowed for the first and second welds. For each 50mm length of the third weld, two pores with a diameter less than 0.4 times the thickness of the parent metal and less than or equal to 3mm are allowed, and the hole pitch is greater than or equal to 6 times the pore diameter. The reasons for the blowholes are: the humidity of the welding environment is large; the welding wire is damp or does not bake according to requirements; there are impurities such as oil, rust, etc. in the weld seam or the cleaning is not complete; the weld seam is not protected, and the welder has a low level of technology. The prevention measures of stomatal include: Attention to monitoring the welding operation environment. Welding is forbidden when the conditions are not met. The welding electrode is purchased, stored, distributed and used according to the system requirements; the impurities such as oil, rust, etc. within 20mm of both sides of the weld are thoroughly cleaned before welding. ; To verify the purity of the protective gas, check whether there is a leak in the barrel; to improve the welder's operating level, adhere to the preferred use.

Slag quality requirements of prefabricated steel structure (steel structure prefabricated workshops,  warehouses), causes and preventive measures

For the first and second welds, surface slag inclusion is not allowed. The depth of the slag inclusion in the third-level welds must be less than or equal to 0.2 times the thickness of the parent material, and the length must be less than or equal to 0.5 times the thickness of the parent material and not exceed 20 mm. The reasons for slag inclusion are: incomplete cleaning before welding or during welding; unreasonable welding groove parameters or group-to-gap clearance; small welding current; unskilled welder operation; The slag prevention measures include: thoroughly clean the welds on both sides of the weld before welding, weld slag cleaning after the welding process; refer to "steel structure welding specifications" select the appropriate groove parameters for processing, improve the parts group For quality; reasonable choice of current and arc length; strengthen welder skills training so that the welding slag can be discharged.

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