Study of the influence of deformation and thermal treatment on the ultrasonic behaviour of steel

Effect of Heat Treatment and Pulse Plasma Process on Surface Properties of Steels

“…The ferrite and perlite structures were seen on surface. Slower cooling rates (in air) led to larger prior austenite grain size, larger amounts of soft ferrite and wider interlamellar spacing between cementite (Fe 3 C) plates of pearlite [6]. The initial microstructure 1050 steel was composed mainly of low carbon martensite laths and dispersed precipitation phases, which can be observed in Fig.…”

“…These rates can initiate mixing, rapid diffusion and formation of amorphous or microcrystalline surface layers. Hence, the mechanical properties of material surfaces can be improved [5,6].…”

Microstructural evolution under tempering heat treatment in AISI H13 hot-work tool steel

“…When hardened steel is tempered, the tetragonality of the martensite decreases and then disappears, which results in [4]. When steel is tempered at 600°C, the following changes in the matrix take place: internal stresses decrease; dislocations annealout; and coalescence of carbides [7]. The secondary hardening is a strengthening resulting of the replacement of coarse particles of Fe3C, which dissolve, by a fine dispersion of alloy carbides such as VC, Cr7C3, Cr23C6, Mo2C or Mo6C.…”

The use of the ultrasound measurement technique for the evaluation of mechanical properties of the ASTM A36 steels

“…Prasad and Kumar, in a study with cast iron (Prasad, 1994), correlated the ultrasonic velocity with the percentage reduction on the lamination of steels with different heat treatments. The study showed a decrease in velocity when increasing reduction, correlating this fact to the increase in material hardening.…”

“…The author describes different methods on the attempt of determining the grain size, by the analysis of the ultrasonic backscattered signals, by the analysis of the attenuation of consecutive back wall echoes and by measuring only the first back wall echo for highly attenuating materials, obtaining an inaccuracy of less than 20% for the last method. Recent work (Prasad and Kumar, 1994) correlated the ultrasonic velocity with the percentage reduction (mechanical hardening) on the rolling process for steels with different thermal treatments.…”