Application of cross joint welds in bridge welding production (5)
(3) The macro-section and joint structure inspection welds are well welded, there are no weld defects, the weld structure is columnar ferrite + pearlite, and there is a small amount of weiss body structure in the overheated zone. The physical and metallographic photographs of the joints are shown in Figure 6 and Figure 7, respectively.
Conclusion
In the cross joint weld, stress concentration of the welded joint due to factors such as joint form, weld shape, welding defects, etc., easily lead to fatigue cracking of the weld and a decrease in the fatigue strength of the base metal. In the welding production process of this bridge, under the premise of ensuring the performance of the bridge deck (Z-direction plate), it should be noted that the thickness of the soldering foot should not be too high and should be kept smooth, especially to prevent the occurrence of undercut at the weld toe. Otherwise, it will directly lead to fatigue fracture of the T-shaped fillet weld. Therefore, the use of reasonable welding process and welding method to improve the fatigue strength of welded joints and prevent fatigue fracture of joints is of great significance for the production and manufacture of steel structures.
Author: the Iron Mountain Bridge Group Co., Ltd. (Hebei Qinhuangdao 066205) Magosawa
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