Influence of Quenching and Tempering Treatment on the Mechanical Property of the X70 Grade Seamless Pipe Steel
The relationships among heat treatment, mechanical property and the microstructure in the industry produced X70 grade quenched and tempered hot rolling seamless pipe steel were studied in this paper. The mechanical property of this grade line-pipe steel reached the API 5L standard by optimizing the quenching and tempering treatment. The X70 grade line-pipe steel was quenched in oil, water and icy salt water at the cooling speed of 20℃/s, 60℃/s and 100℃/s respectively after it was heated to 920℃, then the full quenched samples were tempered at 520℃, 550℃ and 580℃ respectively. By analyzing the microstructure and mechanical property, it showed that the chief influence factor on the mechanical property of the X70 grade line-pipe steel was the cooling speed in the quenching process. If the cooling speed was higher than 60℃/s, more lath martensite could be gained. But if the cooling speed was lower than 60℃/s, it would gain less lath martensite, Widmanstaten structure partially and less massive ferrite, which would seriously affect the mechanical property. The final result of the industry experiment is that the ideal strength and toughness of the X70 grade line-pipe steel can be achieved by heating the steel to 920℃, holding at this temperature for 40 minutes, quenching at the cooling speed more than 60℃/s in water, and tempering at 550℃ for 80 minutes.
quenching and tempering treatment mechanical property cooling speed full quenched industry experiment
Jian Fang Tianbing Xu Zexi Yuan
Wuhan University of Science and Technology Hengyang Hualing Steel Tube Co, Ltd
国际会议
2006现代科技国际研讨会(The International Workshop on Modern Science and Technology in 2006)
北京
英文
44-48
2006-04-01（万方平台首次上网日期，不代表论文的发表时间）