Preparation of Nitrogen-Containing Stainless Steels by Vibration Milling and Cold-Press Sintering
Nitrogen-containing nickel-free Fe-18Cr-10Mn-2Mo stainless steel powders were produced by high-energy vibration ball milling under flowing nitrogen atmosphere. It can be found when milling below 4h, the nitrogen contents of the powders tend to be higher level and their particle sizes reduce with increasing the milling time, but when milling beyond 4h, the particle sizes of the powders could not be further refined and the nitrogen contents of the powders increase quite slowly. During high-energy ball milling, there is no new phase formed in the milled powders. The powders milled for 4h, whose nitrogen content is 0.42%, were cold-pressed and sintered under flowing nitrogen atmosphere. The sintered bodies have a ferrite-austenite duplex microstructure, and obtain a relative density as high as 97.2% and a final nitrogen content of 0.38%. The mechanical tensile properties of the sintered bodies are far superior to those of the nitrogen-containing stainless steel prepared by high nitrogen pressure melting technique.
D. W. Cui "Preparation of Nitrogen-Containing Stainless Steels by Vibration Milling and Cold-Press Sintering", Advanced Materials Research, Vols. 179-180, pp. 162-166, 2011