Showing papers by "Fujio Abe published in 2000"
34 citations
13 citations
TL;DR: In this article, the effect of initial microstructure, martensite, tempered martensites, bainite and ferrite+pearlite, on long term creep strength property up to about 80000 h at 848K has been investigated on a 0.5Cr-0.5Mo low alloy ferritic steel.
Abstract: Synopsis : The effect of initial microstructure, martensite, tempered martensite, bainite and ferrite+pearlite, on long term creep strength property up to about 80000 h at 848K has been investigated on a 0.5Cr-0.5Mo low alloy ferritic steel. No significant effect of tempering after quenching on the long term creep strength has been observed. However, strong effect of transformation process during cooling from austenite has been observed. Creep strength of bainite microstructure is higher than those of martensitic microstructure, independent of tempering after quenching. In the low stress condition in which applied stress is lower than proof stress, creep strength of full annealed microstructure which consists of ferrite and pearlite has been found to be higher than the others. The smallest creep rate of a full annealed microstructure in the long term creep region should be caused by both very low dislocation density of the initial microstructure and small amount of dislocations generated under the low stress condition.
5 citations
Patent•
11 Jan 2000
TL;DR: In this paper, a high Cr ferritic steel, having a composition containing, by weight, 7-12% Cr, either or both of Mo and W as solid solution strengthening elements, is hot worked, subjected to high temperature treatment for ≥5 s at a temperature higher than either of the solid solution forming temperature of the MX-type carbonitride forming elements and the initial temperature of δ-ferrite precipitation.
Abstract: PROBLEM TO BE SOLVED: To provide a high Cr ferritic heat resistant steel improved in toughness at room temperature or below as well as in long time creep characteristic at high temperature independently of its components, and its heat treatment method. SOLUTION: A high Cr ferritic steel, having a composition containing, by weight, 7-12% Cr, either or both of Mo and W as solid solution strengthening elements, and one or more kinds among MX-type carbonitride forming elements, is hot worked, subjected to high temperature treatment for ≥5 s at a temperature higher than either of the solid solution forming temperature of the MX-type carbonitride forming elements and the initial temperature of δ-ferrite precipitation, cooled at a rate of ≥0.5°C/s, and then tempered. COPYRIGHT: (C)2001,JPO
4 citations