Effect of Reverted Austenite on the Mechanical Properties and Toughness of a High Strength Maraging Stainless Steel Custom 450®

One of the problems confronted by a metallurgist, whether in Quality Assurance or Research, is that of the control of austenite in ferritic or martensitic steels. The martensitic transformation in many alloys does not reach 100% completion with the structure containing some amount of “retained Austenite”. Similarly during aging of the maraging stainless steel alloys, “reverted austenite” is formed concurrent with the precipitation of an age-hardening phase. The amount of austenite, retained or reverted, has a marked effect on the properties of these alloys. It should be also mentioned, that in austenitic steels, the formation of delta ferrite during high temperature anneals and the pseudo-martensite formed during cold working, has a marked effect on properties. Therefore, it is desirable to have a means to rapidly and accurately measure the quantity of austenite for quality control and for research problems.