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闪光接触焊“灰斑”的得名是由宏观观察焊缝断口,其缺陷的光学及形貌的特征是较周围正常区域更灰暗,无光泽且平坦光滑小平面而,定义的[1,2]。近年来人们用扫描电镜观察灰斑形态归纳为二类形态:一类为平浅等轴韧窝中有夹杂;另一种为纤维鳞片状拉长孔坑FeO型灰斑。[3,4]。我们对约200个灰斑试样进行观察,归类,分析的基础上,认为灰斑有五种不同的形态,并对成因做了分析。第一种形态灰斑为平浅光滑的等轴韧窝,部份韧窝中有夹杂(图1)。用电子探针和X光衍射得知灰斑区域是2Fe和Si,Al,Mn氧化物或其盐类组成。由化学热力学观点分析[2],对应灰斑形成的机理是在焊接过程中打弧造成局部区域温度过高形成深火口而且在高温时间过长使Mn;Si;Al参加置换Fe和
Flash contact welding “gray spot” is named after the macroscopic observation of the weld fracture, the defect of the optical and topographic features than the surrounding normal area is darker, matte and flat smooth facets, the definition of [1,2 ]. In recent years, people use the scanning electron microscope to observe the morphology of gray spots into two types of morphology: one is shallow shallow equiaxed dimples inclusions; the other is a fibrous scaly elongated hole FeO gray spot. [3,4]. Based on the observation, classification and analysis of about 200 gray speckles samples, we found five different morphologies of gray spots and analyzed the causes. The first form of gray spot is flat and smooth equiaxed dimples, some dimples inclusions (Figure 1). The electron spot and X-ray diffraction revealed that the gray spot area is composed of 2Fe and Si, Al, Mn oxides or their salts. From the point of view of chemical thermodynamics [2], the mechanism of gray spot formation corresponds to the mechanism of arc formation caused by arcing in the welding process, which results in the formation of deep fiery mouth at high temperature in the local area and long time at high temperature so that Mn, Si and Al participate in the replacement of Fe and