Cr-W low alloy heat-resisting steels
1991 Volume 29 Issue 6 Pages 327-334
Details
1991 Volume 29 Issue 6 Pages 327-334
Characteristics such as high temperature strength, toughness, and weldability were investigated with low activation Cr-W-V-Ta steels.
All steels whose tensile strength was adjusted to about 637MPa showed good ductility and toughness.
Absorbed energies at 0°C were more than 196J and shear fraction values of the fractured surfaces were nearly 100%. No steels were embrittled after extended heating at 575°C.
Microstructure of the steel except a 8 Cr-2W-0.25V-Ta steel was tempered bainite and grain size was markedly fine (ASTM No. 7-8).
Creep rupture strength of some steels was equal to or higher than that of the advanced Cr-Mo steels for oil refinery equipments.
According to the results of the JIS maximum hardness test, as welded hardness of a 2.25Cr-2W-0.4V-Ta steel was almost same as that of a 1.25Cr-0.5Mo steel. Required preheating temperature for preventing cracks was 175°C in the y groove crack test.
