HQ130钢焊接粗晶热影响区的显微图像分析

Micro-Image Analysis of Coarse Grain Heat-Affected Zone for Steel HQ130

用 XQF- 2 0 0 0型显微图像分析仪对 CO2 气体保护焊的高强度钢 HQ130粗晶热影响区(CGHAZ)的显微组织构成、区域宽度及晶粒度进行了测定 ,并用透射电镜和电子衍射技术对CGHAZ的精细组织结构作了进一步的研究。结果表明 ,随着焊接线能量的增加 ,HQ130钢CGHAZ的主体组织依次为板条马氏体→板条马氏体 +下贝氏体→板条马氏体 +下贝氏体 +上贝氏体 ,晶粒直径逐渐变大。当焊接线能量为 2 2 .3k J/ cm时 ,奥氏体晶粒的直径最大达 15 8μm。应将焊接线能量控制在 16 k J/ cm以下 ,使 CGHAZ形成板条马氏体 +下贝氏体组织 ,避免产生上贝氏体组织 ,防止晶粒粗化 ,改善该区域的性能。

The relative phase content, as well as the width and grain size of coarse grain heat affected zone (CGHAZ) for high strength steel HQ130 welded by gas shielded arc welding, have been evaluated by means of XQF 2000 micro image analysator. The phase components in the zone have been studied by means of transmission electron microscope and Electron Diffraction. The experimental results indicated that the main phase in CGHAZ is changed from ML、 ML+BL to ML+BL+Bu and the grain becomes coarse with the increase of weld heat input, especially, the maximum austenitic grain size is up to 158 μm when q/v =22.3 kJ/cm. By controlling weld heat input under 16 kJ/cm it is possible to form ML+BL in CGHAZ, without upper bainite and coarse grains, then the performance of the CGHAZ can be improved.