Effect of Cyclic Transformation Treatments on the Structure and Mechanical Properties of Steels.
MANLABS INC CAMBRIDGE MASS
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Cyclic transformation of 4340 steel was employed to evaluate the structural changes and strengthening efficiency of this method of heat treatment. Section sizes up to one-half inch thick were evaluated. The results show a direct relation of austenite grain size and martensite lath size into the micron range. Composite structures with hard surfaces and soft cores can be obtained in one-half inch sections. Conversely, fully hardened structures can be obtained in one-half inch sections by controlling the cycling temperature. The efficiency of the cyclic strengthening treatment is determined by the grain size established as a result of the melting practice. Grain size or subgrain size is a more sensitive indicator of strength than imperfection structure. Yield strengths up to 350,000 psi were achieved in a 4340 steel by a ten percent rolling reduction of a cyclically produces martensite structure. Author
- Properties of Metals and Alloys
- Fabrication Metallurgy