Study on Quenching and Tempering Process of Q960 High Strength Steel for Construction Machinery

To develop the Q960 high-strength quenched and tempered steel plates for construction machinery, the effects of quenching and tempering treating regime on the microstructures and mechanical properties were investigated. The results show that the perfect austenization and fine grain size can be achieved by the optimum quenching process that is quenching temperature 900 degrees C and holding time 20min. Considering performance and production efficiency, the optimum tempering process parameters are found that tempering temperature 600 degrees C and holding time 40min. The excellent overall properties of specimens with tempered sorbite microstructure can be ultimately obtained. The yield strength is 1030MPa, tensile strength 1080MPa, percentage elongation 16.8% and the Charpy impact energy 144J at -40 degrees C. All these indexes come up to the National Standard GB/T 16270-2009.