オーステナイト耐熱鋼の引張クリープおよびねじりクリープ破断特性に及ぼす粒界形状の影響

概要

論文の詳細を見る
Tensile creep and torsional creep rupture tests of a commercial austenitic heat-resistant steel, JIS SUH 38, were conducted at 973 K, using two types of specimens : one with a weak rectilinear grain boundary (WQ) and the other with a strong zigzag grain boundary (FA). It was found that the tensile creep rupture strength of FA specimens was considerably higher than that of WQ specimens, and that all specimens tested showed brittle grain boundary fracture. On the other hand, in torsional creep rupture tests, WQ specimens had comparatively higher strength than FA specimens at a higher stress level, while at lower stress levels, WQ specimens became weaker than FA specimens. In the present test, WQ specimens displayed ductile transgranular fracture at higher stresses, but with decreasing stress, they showed brittle intergranular fracture. In all FA specimens, however, the fracture modes were relatively ductile transgranular irrespective of the stress level. These results were explained by the difference in mean normal stress between tensile creep and torsional creep rupture tests, as well as the difference in grain boundary strength between WQ and FA specimens.
一般社団法人日本機械学会の論文
1995-09-25