Effect of thermal deformation on bainite transformation of plastic mould steel SDFT600

doi:10.13251/j.issn.0254-6051.2022.08.001

Abstract

Abstract: Effect of thermal deformation on bainite transformation of plastic mould steel SDFT600 during continuous cooling was analyzed by means of thermal simulation machine, thermal dilatometer, scanning electron microscope, etc. The results show that with the parameters suitable for forging production of large plastic mould steel blocks, thermal deformation promotes bainite transformation. At same continuous cooling rate, the bainite transformation start temperature of dynamic CCT specimen is higher than that of static CCT specimen, at cooling rate of 0.5 ℃/s, the temperature difference reaches 96 ℃. Thermal deformation reduces the stability of retained austenite, and at cooling rate of 0.5 ℃/s, the bainite content of dynamic CCT specimen is higher than that of static CCT specimen. When the continuous cooling rate is less than 0.1 ℃/s, the content of retained austenite of dynamic CCT specimen is lower than that of static CCT specimen. Hardness uniformity under thermal deformation condition is better, which is beneficial to the final quality of mould blocks.

Key words: plastic mould steel SDFT600, thermal deformation, cooling rate, bainite transformation

CLC Number:

Zhang Zheng, Chen Jinlei, Zhang Min, Qiao Junwei. Effect of thermal deformation on bainite transformation of plastic mould steel SDFT600[J]. Heat Treatment of Metals, 2022, 47(8): 1-6.

References

[1]Firrao D, Matteis P, Scavino G, et al. Relationships between tensile and fracture mechanics properties and fatigue properties of large plastic mould steel blocks[J]. Materials Science and Engineering: A, 2007, 468-470(11/12): 193-200.
[2]Luo Y, Wu X C, Wang H B, et al. A comparative study on non-quenched and quenched prehardened steel for large section plastic mould[J]. Journal of Materials Processing Technology, 2009, 209(14): 5437-5442.
[3]Luo Y, Wu X C, Min Y G, et al. Development of non-quenched prehardened steel for large section plastic mould[J]. Journal of Iron and Steel Research International, 2009, 16(2): 61-67.
[4]张铮, 吴晓春. SDP2新型贝氏体塑料模具钢连续冷却相变与力学性能研究[J]. 热加工工艺, 2019, 48(10): 241-243.
Zhang Zheng, Wu Xiaochun. Study on continuous cooling transformation and mechanical properties of SDP2 new bainite plastic die steel[J]. Hot Working Technology, 2019, 48(10): 241-243.
[5]张铮, 李娜. 贝氏体塑料模具钢SDP1热压缩流动应力及晶粒度的研究[J]. 热加工工艺, 2020, 49(15): 64-67.
Zhang Zheng, Li Na. Study on flow stress and grain size of bainitic plastic die steel SDP1 during hot compression[J]. Hot Working Technology, 2020, 49(15): 64-67.
[6]洪斌, 刘雅政, 周乐育. 变形及冷速对预硬化塑料模具钢P20组织与性能的影响[J]. 金属热处理, 2011, 36(5): 103-106.
Hong Bin, Liu Yazheng, Zhou Leyu. Effect of deformation and cooling rate on microstructure and mechanical properties of P20 pre-hardened plastic mould steel[J]. Heat Treatment of Metals, 2011, 36(5): 103-106.
[7]Zhang R Y, Boyd J D. Bainite transformation in deformed austenite[J]. Metallurgical and Materials Transactions A, 2010, 41(6): 1448-1459.
[8]刘东升, 王国栋, 刘相华, 等. P20钢变形奥氏体连续冷却时的相变规律[J]. 金属学报, 1998, 34(3): 271-277.
Liu Dongsheng, Wang Guodong, Liu Xianghua, et al. Continuous cooling transformation behavior of deformed austenite for plastic die steel P20[J]. Acta Metallurgica Sinica, 1998, 34(3): 271-277.
[9]Chen S P, Rana R, Xiao B, et al. The effects of hot deformation of austenite on the bainite transformation in a Fe-C-Mn-Si-Cr steel[J]. Materials Science Forum, 2018, 941: 486-491.
[10]Sourmail T, Smanio V. Optimisation of the mechanical properties of air cooled bainitic steel components through tailoring of the transformation kinetics[J]. Materials Science and Engineering: A, 2013, 582: 257-261.
[11]Gomez G, Pérez T, Bhadeshia H K D H. Air cooled bainitic steels for strong, seamless pipes Part 1-Alloy design, kinetics and microstructure[J]. Materials Science and Technology, 2009, 25(12): 1502-1507.
[12]WilliamLemos B, Jérémy E, Heiner M, et al. In situ investigation of the bainitic transformation from deformed austenite during continuous cooling in a low carbon Mn-Si-Cr-Mo steel[J]. Metallurgical and Materials Transactions A, 2020, 51: 3627-3637.
[13]Ariza E A, Nishikawa A S, Goldenstein H, et al. Characterization and methodology for calculating the mechanical properties of a TRIP-steel submitted to hot stamping and quenching and partitioning (Q&P)[J]. Materials Science and Engineering: A, 2016, 671: 54-69.
[14]Xie C S, Liu Z D, He X K, et al. Effect of martensite-austenite constituents on impact toughness of pre-tempered MnNiMo bainitic steel[J]. Materials Characterization, 2020, 161: 1-14.
[15]Khlestov V M, Konopleva E V, Mcqueen H J. Kinetics of austenite transformation during thermomechanical processes[J]. Canadian Metallurgical Quarterly, 1998, 37(2): 75-89.