| abstract |
FIELD: metallurgy. n SUBSTANCE: for improving the low temperature impact hardness, the processing line comprises heating device, cooling device and hot processing device arranged in this order. In the device consisting of plurality of hot-processing devices, the cooling device is arranged on the at least one of the hot-processing devices input side. On the hot-processing device output side, the thermostatic equipment is located. Using such process line, the steel cooling down to the predetermined cooling stopping temperature in the cooling system after heating allows to obtain the phase distribution in nonequilibrium state and thus the steel product smaller microstructure can be obtained, including the central wall portion with relatively small amount of processing. n EFFECT: accordingly, even in the thick-walled steel article, in which the processing amount at the wall center cannot be increased, low temperature impact hardness can also be improved. n 6 cl, 5 dwg, 3 tbl |