Thermomechanical processing as a combination of cold rolling and annealing was performed on austenitic stainless steels 301,304 and 304L. Two cold rolling steps each one up to a reduction of 75% were combined with an ...Thermomechanical processing as a combination of cold rolling and annealing was performed on austenitic stainless steels 301,304 and 304L. Two cold rolling steps each one up to a reduction of 75% were combined with an intermediate annealing at 800℃ for 20 min. The final annealing was performed at.the same temperature and time. Cold rolling contributed to martensite formation at the expense of metastable austenite in the studied materials. Austenite in 301 was found to be less stable than that in 304 and 304L. Hence, higher strength characteristics in the as-quenched 301 stainless steels were attributed to the higher volume fraction of martensite. Both α′-martensite and ε-martensite were found to form as induced by deformation. However, the intensity of ε-martensite increased as the stability of austenite decreased. Annealing after cold rolling led to the reversion of austenite with an ultra fine grained structure in the order of 0.5-1 μm from the strain induced martensite. The final grain size was found to be an inverse function of the amount of strain induced martensite. The thermomechanical processing considerably improved the strength characteristics while the simultaneous decrease of elongation was rather low.展开更多
The advanced hot-rolled transformation induced plasticity （TRIP） steel with high tensile strength of 775 MPa, high elongation of 29% and low ductile-brittle transmission temperature less than -80℃ has been develope...The advanced hot-rolled transformation induced plasticity （TRIP） steel with high tensile strength of 775 MPa, high elongation of 29% and low ductile-brittle transmission temperature less than -80℃ has been developed in laboratory based on the common silicon and manganese chemical composition. The experimental results showed that the microstructures were featured with ultra fine grain size less than 5μm, appropriate retained austenite volume fraction around 11.8% and purified ferrite grain, which may result in well balanced mechanical properties for the steel.展开更多
文摘Thermomechanical processing as a combination of cold rolling and annealing was performed on austenitic stainless steels 301,304 and 304L. Two cold rolling steps each one up to a reduction of 75% were combined with an intermediate annealing at 800℃ for 20 min. The final annealing was performed at.the same temperature and time. Cold rolling contributed to martensite formation at the expense of metastable austenite in the studied materials. Austenite in 301 was found to be less stable than that in 304 and 304L. Hence, higher strength characteristics in the as-quenched 301 stainless steels were attributed to the higher volume fraction of martensite. Both α′-martensite and ε-martensite were found to form as induced by deformation. However, the intensity of ε-martensite increased as the stability of austenite decreased. Annealing after cold rolling led to the reversion of austenite with an ultra fine grained structure in the order of 0.5-1 μm from the strain induced martensite. The final grain size was found to be an inverse function of the amount of strain induced martensite. The thermomechanical processing considerably improved the strength characteristics while the simultaneous decrease of elongation was rather low.
文摘The advanced hot-rolled transformation induced plasticity （TRIP） steel with high tensile strength of 775 MPa, high elongation of 29% and low ductile-brittle transmission temperature less than -80℃ has been developed in laboratory based on the common silicon and manganese chemical composition. The experimental results showed that the microstructures were featured with ultra fine grain size less than 5μm, appropriate retained austenite volume fraction around 11.8% and purified ferrite grain, which may result in well balanced mechanical properties for the steel.
