Improved austenitic stainless steel alloys for high temperature applications.

摘要

Austenitic stainless steel alloys which have been found to exhibit improved high temperature stress rupture properties and consist essentially of (in wt.%): 12.5 to 14.5 Cr 14.5 to 16.5 Ni 1.5 to 2.5 Mo 1.5 to 2.5 Mn 0.1 to 0.4 Ti 0.02 to 0.08 C 0.5 to 1.0 Si 0.01 maximum, N 0.02 to 0.08 P 0.002 to 0.008 B 0.004-0.010 S 0.02-0.05 Nb 0.01-0.05 V 0.005-0.02 Ta 0.02-0.05 Al 0.01-0.04 Cu: 0.02-0.05 Co 0.03 maximum, As 0.01 maximum, O 0.01 maximum, Zr and with the balance of the alloy being essentially iron. The carbon content of the alloy is adjusted such that wt.% Ti/(wt.% C + wt.% N) is between 4 and 6, and most preferably about 5. In addition the sum of the wt.% P + wt.% B + wt.% S is at least 0.03 wt.%. This alloy is believed to be particularly well suited for use as fast breeder reactor fuel element cladding.