Accession Number : AD0017303

Title :   MARTENSITIC HIGH CHROMIUM HEAT RESISTANT STEELS

Descriptive Note : Interim technical rept. no. 2, Feb-Aug 52,

Corporate Author : AMERICAN BRAKE SHOE CO MAHWAH N J

Personal Author(s) : FELLOWS,JOHN A.

Report Date : 29 JUL 1953

Pagination or Media Count : 13

Abstract : Experiments were conducted to determine the effect of longer treatment at high temperature on the hardening characteristics of high-Cr steels. Solution treatments of 2, 4, and 8 hr were employed at each of the 3 austenitizing temperatures for 15 steels representing Cr levels of 18, 21, and 24%; Ni levels of minimum, 2, and 3%; N contents of minimum % and .01 x % Cr; and C ranging from 0.23 to 0.56%. Response of hardness levels to length os solution treatment was negligible. Six-hr tempering treatments were superior to 1 hr. Studies were made of structures produced by variations in Ni and N additions to a 0.35%C, 21.0% Cr base alloy. Marked changes in primary ferrite were observed for 4 combinations of 0.12% and 2.17% Ni with 0.06% and 0.23% N; the low-Ni, low-N alloy was more than 75% -structure at 1900 deg F. The high-Ni, high N alloy was austentic at all solution temperatures. Within certain ranges, Ni and N appeared to be nearly equivalent to C in its stability to change phase relationships. Excess carbides were present in nearly all instances. Tensile tests were made on 3 alloys of the 21% Cr group; the low N grades displayed inadequate yield strenght at 2 hardness levels, and unsatisfactory ductility at the higher level. A 2% Ni, low-N alloy resisted softening by tempering treatments at 1100 and 1200 deg F, and showed high yield strength but little ductility.

Descriptors :   ADDITION, ALLOYS, CARBIDES, DUCTILITY, FERRITES, HARDENING, HARDNESS, HIGH RATE, HIGH STRENGTH, HIGH TEMPERATURE, LEVEL(QUANTITY), SOLUTION HEAT TREATMENT, SOLUTIONS(GENERAL), TEMPERATURE, TEMPERING, TENSILE PROPERTIES, TEST AND EVALUATION.

Distribution Statement : APPROVED FOR PUBLIC RELEASE