不锈钢管道焊缝金属疲劳短裂纹行为的实验研究 Ⅰ.材料微观结构和研究方法  

EXPERIMENTAL OBSERVATIONS ON THE SHORT FATIGUE CRACK BEHAVIOUPR OF A STAINLESS STEEL PIPE-WELD METAL Ⅰ- Material Microsturctures and Research Approach

作　　者：赵永翔[1] 高庆[2] 王金诺[1] 

机构地区：[1]西南交通大学机械工程研究所,成都610031 [2]西南交通大学应用力学研究所,成都610031

出　　处：《金属学报》2000年第9期931-936,共6页Acta Metallurgica Sinica

基　　金：国防科委95预研资助项目!27.1.1

摘　　要：用金相、复型技术和硬度实验测试了１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢焊缝金属试样表面的微观结构组成结果表明：奥氏体基体与富δ铁素体－带状结构组成的柱状晶是焊缝材料的微观结构特征，相邻富δ铁素体带间距离（约４０μｍ）是这一结构的特征参量试样表面的微观结构依相对焊缝柱状品取向的不同而不同考虑疲劳损伤的局部性和区别试样表面不同尺度、位置微裂纹对疲劳损伤贡献的差异，提出了以“有效短裂纹准则”Metallurgy replica and microhardness tests are used to observe the surface microstructures of the 1Cr18Ni9Ti stainless steel pipe-weld metal specimens. The results reveal that this material has a columnar grain structure which consists of austenite matrix and rich delta ferrite bands. The distance between rich delta ferrite bands (about 40 μm) is an appropriate parameter for characterizing this structure. The surface microstructures of specimens are related to the orientations of columnar. grain. Considering the localization of fatigue damage and the contributions of short cracks with different sizes and positions to fatigue damage an approach called "effective short fatigue crack criterion" is suggested. This criterion is consisted of three new concepts, effective short fatigue cracks (ESFCs), domings effective short crack (DESFC) and density of ESFCs.

关 键 词：不锈钢管道 焊缝金属 微观结构 有效短裂纹准则 

分 类 号：TG404[金属学及工艺—焊接] TG457.6