焊接贝氏体-奥氏体钢管贝氏体钢侧的巴克豪森效应

Barkhausen Noise Response on the Bainitic Steel Side of Welded Bainitic and Austenitic Steel Pipe

研究了焊接贝氏体－奥氏体钢管贝氏体钢侧显微组织变化和残余应力分布对巴克豪森噪声（ＢＮ）的影响。结果表明，随着离焊缝距离的增加，显微组织可分为四个区域：粗大板条贝氏体加少量板条马氏体区，均匀细小的粒状贝氏体区（正火区），较粗大粒状贝氏体加少许块状铁素体区（过渡区）和原始粒状贝氏体区；轴向残余应力逐渐减小，周向残余应力的分布特征不明显；ＢＮ振铃计数率在焊缝贝氏体钢侧具有最大值而在距其１０ｍｍ处降至最低值，此后有逐渐回升趋势。对试验结果进行了分析与讨论。

The effects of change in microstructure and residual stress distribution on Barkhausen noise (BN) on the bainitic steel side in a welded bainitic and austenitic steel pipe are studied. Test results show that with the increase of distance from the weld fusion line the microstructure on the bainitic steel side could be divided into the following four regions. They were coarse lath bainite plus martensite region, uniform and fine granular bainite (normalized structure) region, coarser granular bainite plus a small amount of block-like ferrite region (transient region) and original granular bainite region. The residual stress along the longitudinal direction of the pipe after welding was gradually decreased with the increase of distance from the weld fusion line while the characteristic of the residual stress along the peripheral direction of the pipe was not obvious. The ringdown count rate of BN had the highest value near the fusion line and the lowest one at a 10mm distance from the fusion line on the bainitic side, then tended to increase gradually. The test results are analyzed and discussed in the paper.