Accession Number : AD0700036

Title :   KINETICS OF CARBURIZATION OF FOUR AUSTENITIC STAINLESS STEELS.

Descriptive Note : Rept. for Jul 68-Jun 69,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Stanley,James K.

Report Date : 26 NOV 1969

Pagination or Media Count : 26

Abstract : Four austenitic stainless steels of the 18Cr 8Ni type (i.e., AISI types 304, 316, 321, and 347) were carburized in a methane-hydrogen mixture (1.5 vol% methane) in a temperature range from 925C (1700F) to 1040C (1900F). Carbon gradients were established by analyzing layers machined from carburized steels. Despite the heterogeneous appearance of the microstructure in the carburized layer, it was possible to calculate diffusion coefficients for each of the four steels. The diffusion coefficients are assumed to represent several metallurgical phenomena such as bulk and grain boundary diffusion and nucleation and growth of the Fe.Cr7C3 carbide. Activation energies Q for the four steels were determined. The activation energy was the lowest for Type 321 (the titanium stabilized steel) and the highest for Type 304. Metallographic structures of each steel demonstrate the complex morphology of the carburized structure. (Author)

Descriptors :   (*STAINLESS STEEL, *CASE HARDENING), AUSTENITE, MICROSTRUCTURE, DIFFUSION, HEAT OF ACTIVATION

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE