T91钢焊缝及热影响区显微组织图象分析

T91钢具有良好的高温抗氧化性和抗腐蚀性，该钢含8％－9．5％Cr，合金含量复杂，焊接难度大，运用金相显微镜和扫描电镜（SEM）分析了不同爆接工艺条件下T91耐热钢焊缝及热影响区或区域显微组织特征，利用XQF－2000型显微图象分析仪对显微组织中各相的相对含量和奥氏体晶粒度进行了测量，分析了焊接线能量对T91钢焊接接头区组织性能的影响，结果表明，采用多道焊焊接工艺，严格控制焊接线能量在16kJ/cm左右，可以防止T91钢焊缝区奥氏体晶粒粗大，避免在热影响区出现声状铁素体组织，从而保证焊接接头区具有良好的组织性能。

Image analysis of microstructure in the weld metal and heat affected zone of T91 steel

Steel T91 has excellent oxidation and corrosion resistance under the condition of high temperatures. It consists of 8%~9.5%Cr with complicated alloy content, and is, therefore, very difficult to be welded. In this paper, the microstructure features in the welded metal and heat affected zone of heat-resistant steel T91, which was welded by different processes, are analyzed through metallography and SEM techniques. The relative content of the phases in microstructure and austenite grain size are evaluated by means of XQF-2000 micro-image analyser. In addition, effects of weld heat input on microstructure and performance of the weld joints are analyzed. The test results indicate that by controlling weld heat input about 16kJ/cm and practicing multi-layer weld process, the coarse austenitic grains in the weld metal and lumpish ferrite in the heat affected zone can be avoided so that the microstructure and performance of the weld joints can be ensured.