基于07MnNiMoDR钢热处理工艺窗口的热处理工艺

Relationship between quenching and tempering prcesses and grain size and polygonal ferrite content of the 07MnNiMoDR steel was studied, and the austenite size window and tempered polygonal ferrite content window during quenching and tempering were established, and a more precise heat treatment process was determined. The results show that the austenite grain size increases with the increase of austenitizing temperature and holding time, and there is an optimal range of uniformity. The reasonable quenching process is heating at (940±10)℃ and holding for (80±10) min. When the temperature rises, polygonal ferrite appears at about 650℃, of which content increases with the increase of tempering temperature and holding time. The reasonable tempering process is heating at (665±5)℃ for (165±15) min. The optimal heat treatment process consists of quenching at 940℃ for 80 min and tempering at 660℃ for 180 min. The final performance test results show that the elongation, impact absorbed energy and yield strength are increased by 40.88%, 206.25% and 12.1%, respectively, compared with the national standard.