Abstract
Strange silver white spot illustrated in photo. 2 appeared in the tensile test specimen of thick weld metal which is free from weld cracking. We studied the cause of the phenomenon, the result obtained is as follows.
(1) Strange silver white spot in photo. 2 is enlarged fish eye.
(2) Silver white spot in tensile specimen have two kind, one is fish eye, and the other is micro weld cracking.
(3) Micro weld cracking includes small columnar structure and fish eye does not include it. Difficulties to judge the strange silver white spot in tensile specimen the micro weld cracking is solved by finding small columnar rstructure in fracture surface. i.e. Micro welding crack includes small columnar structure and fish eye does not include it.
