Research on Heat Treatment Technology of High Strength and High Toughness Casting Lock Ring for Dredging Ship

The lock ring is the key component at the pipeline interface of dredging ship, which bears a large load and requires high strength and toughness of the material. The heat treatment technology of a kind of steel for high strength and high toughness casting lock ring for dredged marine was studied.The results show that when the quenching temperature is 890 ℃, the strength of the test steel decreases and the elongation after break increases with the increase of tempering temperature.After water quenching at 890 ℃and tempering at 620 ℃, the microstructure is tempered martensite, and the hardness and impact work are 34 HRC and 29 J, respectively, the strength and toughness of the material are well matched.