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通过焊接热模拟及焊接接头多次补焊试验,分析了转向架SMA490BW钢焊接过热区多次补焊后的组织与冲击性能变化。结果表明:SMA490BW钢经历3次及以上峰值温度为1320℃的焊接热循环后,过热区形成粗大的魏氏组织,导致冲击性能显著降低。为此,在接头返修时,根据缺陷尺寸及位置,若将挖补区限制在焊缝内部,且离开熔合线一定距离,多次补焊后再进行(590±15)℃×2h退火处理,则过热区冲击性能明显改善,并优于焊态下过热区的冲击性能。
Through the welding heat simulation and multiple welding tests, the microstructure and impact properties of the welded overheat zone of the bogie SMA490BW after repeated welding were analyzed. The results show that the SMA490BW steel experiences three or more welding cycles with a peak temperature of 1320 ℃, forming coarse Widmanstatten in the overheated zone, resulting in a significant decrease in impact properties. Therefore, when reworking the joint, if the excavation area is limited to the inside of the weld according to the size and position of the defect, a distance of 590 ± 15 ° C × 2h is required after the welding is repeated several times after the weld is repaired Overheat zone impact performance improved significantly, and better than the over-heated zone under the impact properties.