Patent ID: 8852362
Filing Date: 2014-10-07
Classification: B21C,B21K,C21D,C22C,F16L,F22B,F28F,Y10S,Y10T

Abstract:
1. An austenitic stainless steel pipe having steam oxidation resistance which contains, by mass percent, 14 to 28% of Cr and 6 to 30% of Ni, wherein a region satisfying Formula (1) exists in a metal structure at least in one location of 10 to 15 μm in a depth range from an inner surface of the steel pipe and the region is formed by blasting shots or sands: where g in Formula (1) is a value calculated from Formula (2), where the meanings of symbols in Formula (2) are as follows; g: volume ratio (%) α: sum total of the number of pixels of digital image in region in which orientation difference of adjacent crystals detected by electron backscattering pattern is 5 to 50 degrees β: the number of total pixels of digital image in region of measurement using electron backscattering pattern ε: analysis pitch width of electron backscattering pattern (μm) δ: grain boundary width (μm).