The phase transformation rule, microstructures and properties of JG590 high strength steel
produced in Jinan Iron and Steel Co. ltd. have been investigated in this paper. When the chemical
composition of steel are given, the cooling rates after finished rolling affect on the properties of steel
greatly. The yield strength and tensile strength increasing, the elongation and reduction of area
decreasing as increasing of cooling rates after rolling. The main cause is due to appearance and
increasing of Bainite and Martensite other than Ferrite and Pearlite in room temperature. The finished
rolling temperature have distinct effects upon the mechanical properties of steel plates. Finished
rolling at different temperature with the 0.5°C/s cooling rate, the tensile strength vary in 599-698MPa,
the yield strength changed from 412 MPa to 536MPa. The elongation is between 30.4-40.5%. But
when finished rolling at different temperature with the 2.0°C/s cooling rate, the tensile strength vary
in 747-784MPa, the yield strength changed from 441 MPa to 601MPa. The strength index can both
meet the requirements of employ. But the elongation is only 18.7-24.5%. This is related with
production of lots of Bainite microstructure more than 2°C/s cooling rate. In the procedure of
manufacture of JG590 high steel, the quickly cooling rate should be avoided to keep suitable
microstructure and good elongation and toughness.
Study on Phase Transformation in Hot Stamping Process of USIBOR® 1500 High-Strength Steel
