DETERMINATION OF ENGINEERING PROPERTIES OF MAR-STRAINED STEELS
Technical documentary rept.
GENERAL ELECTRIC CO EVANDALE OH
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The Mar-Strain response the addition of strain and aging to quenched and tempered steels was determined for eight alloys representing four classes of steel low alloy martensitics, secondary hardening martensitics hot work die steels, semi-austenitic and martensitic stainless. All four alloy classes responded to the process by demonstrating yield strength increases of 10 to 20. It was found that the tempered structure and strain hardening characteristics were the most significant factors controlling the Mar-Strain response. Two alloys were selected for determination of their engineering properties including uniaxial tensile, fatigue and center notch properties and biaxial performance in subscale cylinder tests. One alloy, Ladish D6AC .46C, 1Cr, 1Mo, was capable of being MarStrained to a 275,000 psi .2 yield strength. A second alloy, Modified S-5 0.48C, 2Si, 0.5Mo, 0.25V, was capable of being Mar-Strained to a 300,000 psi 0.2 yield strength. Mar-Straining was found to increase the fatigue strength of both alloys. The process was adequately demonstrated in the sub-scale pressure vessel tests. Burst strengths greater than 350,000 psi hoop achieved with the Mar-Strained S-5 cylinders were higher than any previously reported for a homogeneous material.
- Properties of Metals and Alloys