THE CARBURIZATION OF FOUR AUSTENITIC STAINLESS STEELS.
Abstract
Four austenitic stainless steels (AISI Types 304 (18Cr-8Ni), 316 (18Cr-8Ni + Mo), 321 (18Cr-8Ni + Ti), and 347 (18Cr-8Ni + Cb)) were carburized in a mixture of methane-hydrogen (1-1/2 vol % methane) up to 25 hr in a temperature range of 730C (1350F) to 1040C (1900F). Carburization occurrence diagrams, i.e., time and temperature at which carburization is observed, for each of the steels are given. Typical carburized structures at 100x and 500x are given. For this work, the carburized layer was considered to comprise both zones. Photographs at 500x show the complexity of the carbide-austenite zone. The carbide formed in all cases was Cr7C3. The rate of carburization, case depth versus time, is given for each of the steels at temperatures from 870C (1600F) to 1040C (1900F). The general form of the curves is parabolic. The carburization rate for titanium-bearing Type 321 is slightly different from that of the other materials. Microhardness (Knoop) traverses were made on several of the steels, and hardness gradients for each of the steels were established. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 15, 1969
- Accession Number
- AD0694511
Entities
People
- James K. Stanley
Organizations
- The Aerospace Corporation