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运用扫描电镜、x射线能谱仪、离子探针、超声波探伤仪及x射线探伤、金相技术等多种手段对16M_ng钢焊缝中鱼眼白点的形成过程作了综合研究。结果表明,在外加拉应力作用下,鱼眼白点的形核机制可分为如下两个阶段。第一阶段与延性韧窝的形成过程相同,产生微孔、微裂纹;第二阶段是氢助裂纹作用使微裂纹迅追扩展而成为白点核。这种白点核可能是沿晶也可能是穿晶裂口。最后,鱼眼白点以局部脆断形式突然长成。
The forming process of fish eye white spots in 16M_ng steel weld was comprehensively studied by means of scanning electron microscopy, X-ray energy dispersive spectrometer, ion probe, ultrasonic flaw detector, x-ray flaw detection and metallographic techniques. The results show that under the action of external tensile stress, the mechanism of nucleation of white spots in fish eyes can be divided into the following two stages. In the first stage, ductile dimples are formed in the same process, resulting in micropores and micro-cracks. In the second stage, the role of hydrogen-assisted cracking is to accelerate the propagation of micro-cracks and become white spots. This white point nucleus may be along the crystal may also be translucent. Finally, the fisheye suddenly grows in the form of partial brittleness.