Thermodynamics and kinetics of solution nitriding

Phase transformation during intercritical tempering with high heating rate in a Fe-13%Cr-4%Ni-Mo stainless steel

“…This phenomenon may be interpreted as the martensite to austenite phase transformation being a diffusionless transformation in the intercritical tempering with high heating rate. Most of the reversed austenite grains have the same orientation as the prior austenite formed in normalizing [7,13,17] . When the cooling process in tempering begins, the austenite transforms to the same variants of the normalized martensite again.…”

“…Thus, the diffusionless transformation and higher A s temperature render it difficult for any austenite to remain at room temperature in the sample tempered at 993 K with the heating rate of 50 K/s. When the heating rate is low, the sample tempered in the temperature range from A s to A s +100 K may have some reversed austenite at room temperature [4,5,7] . The amount of austenite in a series of samples, which were tempered at 953, 973 and 1023 K with heating rate of 50 K/s and holding time of 900 s (i.e.…”

Investigation of hydrogen transport behavior of various low-alloy steels with high-pressure hydrogen gas

“…In diffusion analysis involving surface reaction of hydrogen, the local hydrogen content at the surface of the exit side c surf is assumed to be not zero [39], unlike the case of diffusion analysis without consideration of the surface reaction of hydrogen. Therefore, the value of c surf was determined so that the following equation was satisfied:…”