Industrial Production of 780 MPa Grade Tempering Steel Plates for Cold Forming and for Hot-Strip Rolling
ZENG Bin1,2， SUN Xin-jun2， LI Zhao-dong2， YONG Qi-long2， WENG Yu-qing2
1. Technical Center of Lianyuan Iron and Steel Co.， Ltd.， Loudi 417009， Hunan， China 2. Department of Structural Steels， Central Iron and Steel Research Institute， Beijing 100081， China）
Abstract：Leveled steel plates were taken from hot-rolled strip steel with tensile strength of 780 MPa, which had been?widely?used?in building cranes and concrete pump trucks by cold forming. In the present work, the plates were tempered on a production line, and their mechanical properties, welding performance, cold forming property and microstructures were investigated. The results show that the strength and hardness of the steel increased significantly after the tempering, while the impact toughness and elongation rate decreased slightly. The difference between the mechanical properties in transverse direction and these in longitudinal direction decreased due to the tempering. The mechanical properties of the welded joints were improved showing reduced strength-loss after welding. The cold forming performance was also greatly improved. No significant change in phase constituents was observed due to the tempering, however, some ferrites grains were coarsened and their dislocation density decreased associated with increasing of cellular dislocation. Increased precipitates containing Ti, Nb, Mo were observed, resulting in the precipitation hardening.
曾 斌 ， 孙新军， 李昭东， 雍岐龙， 翁宇庆. 780 MPa级冷成型用热连轧回火钢板的工业化生产[J]. 钢铁, 2014, 49(11): 74-79.
ZENG Bin， SUN Xin-jun， LI Zhao-dong， YONG Qi-long， WENG Yu-qing. Industrial Production of 780 MPa Grade Tempering Steel Plates for Cold Forming and for Hot-Strip Rolling. Iron and Steel, 2014, 49(11): 74-79.
FUNAKAWA Y. SHIOZAKI T. TOMITA K. YAMAMOTO T. MAEDA E. Development of High Strength Hot-rolled Sheet Steel Consisting of Ferrite and Nanometer-sized Carbides[J]. ISIJ International, 2004, 44(11): 1945-1951.
[1]
FUNAKAWA Y. SHIOZAKI T. TOMITA K. YAMAMOTO T. MAEDA E. Development of High Strength Hot-rolled Sheet Steel Consisting of Ferrite and Nanometer-sized Carbides[J]. ISIJ International, 2004, 44(11): 1945-1951.
[2]
Kagechika H. Recent Progress and Future Trends in the Research and Development of Steel[J]. NKK TECHNICAL REVIEW, 2003, 88: 6-9.
[2]
Kagechika H. Recent Progress and Future Trends in the Research and Development of Steel[J]. NKK TECHNICAL REVIEW, 2003, 88: 6-9.
[3]
Misra R D K. Nathani H. Hartmann J E. Siciliano F. Microstructural Evolution in a New 770 MPa Hot Rolled Nb–Timicroalloyed Steel[J]. Materials Science and Engineering A, 2005, 394: 339-352.
[3]
Misra R D K. Nathani H. Hartmann J E. Siciliano F. Microstructural Evolution in a New 770 MPa Hot Rolled Nb–Timicroalloyed Steel[J]. Materials Science and Engineering A, 2005, 394: 339-352.
[4]
Naoki N. Matthias M. Modeling of Microstructure Evolution during Hot Rolling of a 780 MPa High Strength Steel[J]. ISIJ. International, 2005, 45(1): 82-90.
[4]
Naoki N. Matthias M. Modeling of Microstructure Evolution during Hot Rolling of a 780 MPa High Strength Steel[J]. ISIJ. International, 2005, 45(1): 82-90.
Bracke L. Wispelaere N D. Ahmed H. Güng?r ? E. S700MC/Grade 100 in heavy gauges: industrialisation at ArcelorMittal Europe. Revue de Métallurgie, 2011,108: 323-330.
[6]
Bracke L. Wispelaere N D. Ahmed H. Güng?r ? E. S700MC/Grade 100 in heavy gauges: industrialisation at ArcelorMittal Europe. Revue de Métallurgie, 2011,108: 323-330.
[7]
Suikkanen P. Development and Processing of Low Carbon Bainitic Steels[D]. Linnanmaa: UNIVERSITY OF OULU, 2009.
[7]
Suikkanen P. Development and Processing of Low Carbon Bainitic Steels[D]. Linnanmaa: UNIVERSITY OF OULU, 2009.
2014, Vol. 49 
