复合渗铝钢管焊接HAZ渗铝层相组成特征

Phase constiution characteristics of Fe-Al alloy layer in HAZ of calorised steel pipe

采用光镜、电镜、Ｘ射线衍射和电子衍射等测试技术对电感应料浆法（ＧＬ）渗铝钢管焊接接头区域的力学性能和热影响区（ＨＡＺ）渗铝层的相结构特征进行了研究。试验结果表明，ＧＬ渗铝钢管焊接ＨＡＺ渗铝层主要是由ａ－Ｆｅ（Ａｌ）固溶体、Ｆｅ＿３Ａｌ相和ＦｅＡｌ相构成，渗铝层中不存在含铝较高的ＦｅＡｌ＿２、Ｆｅ＿２Ａｌ＿５和ＦｅＡｌ＿３等脆性相。显著改善了渗铝钢管的承受变形能力和焊接性，使焊接接头区域的组织与性能容易得到保证。

Mechanical properties of welding region and phase constitution characteristics of the Fe-Al alloy layer in HAZ of calorised steel pipes are researched by means of metallography,SEM,TEM,X-ray diffractometer and electron diffraction,etc. Experimental results indicate that the Fe-Al alloy layer in HAZ of calorised steel pipe is mainly composed of FeAl,Fe_3Al and a-Fe(Al) solid solution, and has no higher aluminium content phases,such as brittle FeAl_2, Fe_2Al_5 and FeAl_3 phases,The deformation ability and the weldability of the calorised steel pipe are remarkably improved. Microstructure and performance of the welding region on calorised steel pipe can be easily ensured.