Effects of Tempering Temperature on Microstructure and Mechanical Properties for Q960 High-Strength Structural Steel Plates

To develop the Q960 high-strength quenched and tempered structural steel plates,the effects of tempering temperature on the microstructure and mechanical properties of plate specimens were investigated on the same rolling and quenching conditions.The results show that with the increase of tempering temperature,the strength values of specimens are reduced,and the toughness and ductility show a mainly increasing tendency.But the temper brittleness appears at 300-450 ℃.The excellent overall properties of specimens with tempered sorbite can be obtained when the tempering temperature is 600 ℃,i.e.,the yield strength is 1 030 MPa,tensile strength 1 080 MPa and percentage elongation 15.9% with the Charpy impact energy 144 J at-40 ℃.All these indexes come up to the National Standard GB/T 16270-2009.Then the tensile behavior of specimens was discussed.