KINETICS OF CARBURIZATION OF FOUR AUSTENITIC STAINLESS STEELS.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 26, 1969
- Accession Number
- AD0700036
Entities
People
- James K. Stanley
Organizations
- The Aerospace Corporation