Thermomechanical Processing of Ferrous Alloys

IMPROVING BOTH Klc AND CVN FRACTURE ENERGY OF AISI 4340 STEEL THROUGH HIGH TEMPERATURE THERMOMECHANICAL TREATMENT

“…This enhancement has been attributed to the presence of thin films of retained austenite between martensite laths, segregation effects, dissolution of carbides, e t c However, concurrent with this improvement in K. there is a perplexing reduction in the charpy impact energy (Ritchie, Francis and Server, 1976). Similar behavior has been reported in 300-M steel (McDarmaid, 1973) 0 It is well known that thermomechanîcal treatments bring out many beneficial microstructrual changes and hence improved mechanical properties (Kula and Azrin, 1978) 0 Therefore, the aim of the present investigation is to examine the influence of thermomechanîcal treatments at high austenitizing temperatures on the toughness properties of AISI 43^0 steel 0 EXPERIMENTAL The material used in this investigation was aircraft quality (vacuum-arcmelted) AISI 43^0 hot rolled bars of 51 mm thickness obtained from Latrobe Steel Company, in fully annealed condition and having the following composition (wt. percent): As-received steel rods were given the following treatment:…”

“…It is known that the HTMT of steels improves mechanical properties such as toughness, ductility and strength (Kula and Azrin, 1978;Azrin and co-workers, 198θ). It is known that the HTMT of steels improves mechanical properties such as toughness, ductility and strength (Kula and Azrin, 1978;Azrin and co-workers, 198θ).…”

A Review: Ferritic-Martensitic Steels – Treatment, Structure and Mechanical Properties

“…Thermal and thermomechanical treatment of steels and alloys are used for structure modernization and improving of mechanical, physical, radiation and other properties [88][89][90][91].…”

A multi-scale model of martensitic transformation plasticity

“…Kula and Azrin, 1978;Olson, 1984;Stringfellow et al, 1992). Therefore, for a continuum point in the martensite, the rate _ F M should only depend on the rates of the elastic and plastic deformations, _ F e M and _ F p M .…”

“…Moreover, due to the inheritance of the austenite dislocation structure by the martensite, the martensite formed at higher stain levels is harder than the initial martensite formed at lower stain levels (see e.g. Kula and Azrin, 1978;Olson, 1984;Stringfellow et al, 1992). Accordingly, the equivalent plastic strain in the martensite e p M is split in two contributions: e p MM resulting from the plastic yielding of the martensite itself andẽ p A reflecting the equivalent plastic stain ''inherited" from the austenite…”