Measurement of CCT curves and carbide intergranular precipitation temperature of 4Cr5Mo2V hot-working die steel

doi:10.13251/j.issn.0254-6051.2024.09.012

Abstract

Abstract: Microstructure and hardness of 4Cr5Mo2V steel at different cooling rates were observed and measured by using thermal expansion meter, resistance meter and hardness tester, combined with scanning electron microscope and energy dispersive spectroscopy. CCT curves of the tested steel were plotted, and the temperature of carbide intergranular precipitation in the steel was determined. The results show that as the cooling rate decreases, the hardness decreases and the microstructure transforms into martensite, bainite and pearlite in sequence. The critical cooling rates for pearlite and bainite transformation are 0.015 ℃/s and 0.25 ℃/s, respectively. When the cooling rate is not greater than 0.25 ℃/s, carbides precipitate along the grain in the steel, and as the cooling rate decreases, the temperature of carbide precipitation along the grain increases. At a cooling rate of 0.01 ℃/s, the highest precipitation temperature is 1022 ℃.

Key words: 4Cr5Mo2V hot-working die steel, cooling rate, CCT curve, intergranular carbides, precipitation temperature

CLC Number:

TG142.7

Gao Xingcheng, Wu Boya, Wu Xiaochun. Measurement of CCT curves and carbide intergranular precipitation temperature of 4Cr5Mo2V hot-working die steel[J]. Heat Treatment of Metals, 2024, 49(9): 72-79.

References

[1]Kang J H, Park I W, Jae J S, et al. A study on die wear model of warm and hot forgings[J]. Metals and Materials, 1998, 4(3): 477-483.
[2]Ebara R. Fatigue crack initiation and propagation behavior of forging die steels[J]. International Journal of Fatigue, 2010, 32(5): 830-840.
[3]白嘉远. 铝合金材料的应用及其加工成形技术[J]. 世界有色金属, 2017(14): 272-273.
Bai Jiayuan. Application of aluminum alloy material and its forming technology[J]. World Nonferrous Metals, 2017(14): 272-273.
[4]王春涛, 姚杰. 压铸铝合金的研究进展[J]. 模具工业, 2019, 45(8): 1-5.
Wang Chuntao, Yao Jie. Research progress of die casting aluminum alloy[J]. Mould Industry, 2019, 45(8): 1-5.
[5]岛村祐太, 舘幸生, 中間一夫, 等. 合金元素对热作模具钢高温强度的影响及新型压铸模用钢的研制[J]. 于红, 译. 模具制造, 2021, 21(12): 84-89.
[6]宋雯雯, 闵永安, 吴晓春. 热作模具钢SDH8与H13的强韧性对比研究[J]. 金属热处理, 2008, 33(9): 59-61.
Song Wenwen, Min Yongan, Wu Xiaochun. Comparative studies on strength and toughness of SDH8 and H13 hot work steel[J]. Heat Treatment of Metals, 2008, 33(9): 59-61.
[7]赵成志, 金天文, 符策鹄, 等. 预处理工艺对热作模具钢5Cr8MoNi2SiV组织与硬度的影响[J]. 金属热处理, 2016, 41(1): 29-34.
Zhao Chengzhi, Jin Tianwen, Fu Cehu, et al. Influence of pretreatment process on microstructure and hardness of hot-work die steel 5Cr8MoNi2SiV[J]. Heat Treatment of Metals, 2016, 41(1): 29-34.
[8]吴远辉, 左鹏鹏, 白植雄, 等. 淬回火工艺对压铸模具钢4Cr5Mo2V强韧性及组织影响[J]. 模具制造, 2017, 17(6): 93-97.
Wu Yuanhui, Zuo Pengpeng, Bai Zhixiong, et al. Effect of quenching and tempering process on strength, toughness and microstructure of die-casting die steel 4Cr5Mo2V[J]. Die and Mould Manufacture, 2017, 17(6): 93-97.
[9]张学友, 左鹏鹏, 何西娟, 等. 氮含量对热作模具钢4Cr5Mo2V热疲劳性能的影响[J]. 金属热处理, 2017, 42(1): 9-14.
Zhang Xueyou, Zuo Pengpeng, He Xijuan, et al. Effect of nitrogen content on thermal fatigue property of hot work die steel 4Cr5Mo2V[J]. Heat Treatment of Metals, 2017, 42(1): 9-14.
[10]林鹏, 马党参, 胡连新, 等. 压铸用模具钢4Cr5Mo2V的过冷奥氏体连续冷却转变[J]. 金属热处理, 2018, 43(6): 16-20.
Lin Peng, Ma Dangshen, Hu Lianxin, et al. Continuous cooling transformation of super-cooled austenite of die steel 4Cr5Mo2V for die-casting[J]. Heat Treatment of Metals, 2018, 43(6): 16-20.
[11]李红英, 王法云, 曾翠婷, 等. 3Cr2Mo钢CCT曲线的测定与分析[J]. 中南大学学报, 2011, 42(7): 1928-1933.
Li Hongying, Wang Fayun, Zeng Cuiting, et al. Determination and analysis of CCT curves of 3Cr2Mo steel[J]. Journal of Central South University, 2011, 42(7): 1928-1933.
[12]张进峰. 中低碳钢碳扩散行为的电阻和内耗方法研究[D]. 上海: 上海大学, 2021.
Zhang Jingfeng. Study on carbon diffusion behaviors of medium and low carbon steels by resistance and internal friction methods[D]. Shanghai: Shanghai University, 2021.
[13]Park B J, Choi J M, Lee K J. Analysis of phase transformations during continuous cooling by the first derivative of dilatation in low carbon steels[J]. Materials Characterization, 2012, 64: 8-14.
[14]邹仲平, 路峰, 于浩, 等. 50Mn2V 钢连铸坯CCT曲线测定及热塑性分析研究[J]. 热加工工艺, 2019, 48(2): 76-80, 86.
Zou Zhongping, Lu Feng, Yu Hao, et al. Research on determination of CCT curve and thermoplastic analysis of 50Mn2V steel continuous casting billet[J]. Hot Working Technology, 2019, 48(2): 76-80, 86.
[15]曹瑞芳, 王福明, 李长荣, 等. Mo对R5系泊链钢过冷奥氏体连续冷却转变曲线[J]. 金属热处理, 2010, 35(5): 6-10.
Cao Ruifang, Wang Fuming, Li Changrong, et al. Effect of Mo on austenite continuous cooling transformation curves of R5 off shore mooring chain steel[J]. Heat Treatment of Metals, 2010, 35(5): 6-10.
[16]Krielaart G P, Zwaag S V. Simulations of pro-eutectoid ferrite formation using a mixed control growth model[J]. Materials Science and Engineering A, 1998, 246(1/2): 104-116.
[17]Donachie S J, Ansell G S. The effect of quench rate on the properties and morphology of ferrous martensite[J]. Metallurgical Transactions A, 1975, 6(10): 1863-1875.