Continuous cooling transformation and normalizing process of EH36-Z35 steel for offshore platform

doi:10.13251/j.issn.0254-6051.2023.07.035

Abstract

Abstract: Continuous cooling transformation curves of EH36-Z35 steel for offshore platform were obtained by using thermal simulation testing machine, and the microstructure of the steel under different normalizing processes was studied by using optical microscope to find out the reason of normalizing underheated structure appeared in production and to optimize the normalizing process. The results show that the Ac₃ of the EH36-Z35 steel is 859 ℃, and the high temperature transformation structure of ferrite+pearlite can be obtained under the cooling rate of <2 ℃/s. Under the same cooling process, underheated structure appears after normalizing at 820 ℃ and 850 ℃, while normal ferrite plus dispersed pearlite is obtained after normalizing at 890 ℃. Through changing the heating rate and cooling rate, the reasonable normalizing process of the EH36-Z35 steel is as taking 130 min to heat from room temperature to 890 ℃, holding for 10 min, cooling to 730 ℃ with a cooling rate of 5 ℃/s, then cooling to 650 ℃ with a cooling rate of 0.2 ℃/s, and then cooling to 400 ℃ with a cooling rate of 0.15 ℃/s, followed by air cooling.

Key words: EH36-Z35 steel, normalizing, continuous cooling phase transformation, offshore platform steel

CLC Number:

TG142.1

Xiao Hongliang, Zhang Huijie. Continuous cooling transformation and normalizing process of EH36-Z35 steel for offshore platform[J]. Heat Treatment of Metals, 2023, 48(7): 201-204.

References

[1]张承泽, 王胜, 龚宝明, 等. EH36钢埋弧焊接头焊缝金属不均匀性对断裂行为的影响[J]. 焊接学报, 2018, 39(1): 9-12.
Zhang Chengze, Wang Sheng, Gong Baoming, et al. Effect of weld metal inhomogeneity on fracture behavior of EH36 steel submerged arc welded joints[J]. Transactions of the China Welding Institution, 2018, 39(1): 9-12.
[2]Kong X W, Lan L Y. Optimization of mechanical properties of low carbon bainitic steel using TMCP and accelerated cooling[J]. Procedia Engineering, 2014, 81: 114-119.
[3]Lee C H, Shin H S, Park K T. Evaluation of high strength TMCP steel weld for use in cold regions[J]. Journal of Constructional Steel Research, 2012, 74: 134-139.
[4]孙宪进, 张明, 王小双, 等. 易焊接性E690海工钢热处理工艺与性能关系的研究[J]. 热加工工艺, 2016, 45(20): 236-238.
Sun Xianjin, Zhang Ming, Wang Xiaoshuang, et al. Research on relationship between heat treatment process and properties of E690 easy-welded offshore steel[J]. Hot Working Technology, 2016, 45(20): 236-238.
[5]卓晓, 李立新, 李弟, 等. EH36-Z35钢在低温环境中的焊接冷裂纹敏感性[J]. 机械工程材料, 2020, 44(8): 47-51.
Zhuo Xiao, Li Lixin, Li Di, et al. Welding cold crack sensitivity of EH36-Z35 steel in low temperature environment[J]. Materials for Mechanical Engineering, 2020, 44(8): 47-51.
[6]杨春卫, 白学军, 冯路路. 高强度船体及海洋工程用钢EH36-Z35的开发[C]//2012年全国轧钢生产技术会论文集(下). 2012: 586-592.
Yang Chunwei, Bai Xuejun, Feng Lulu. The development of high-strength hull and off-shore platform plate steel EH36-Z35[C]//2012 National Steel Rolling Production Technology Conference Proceedings (Part 2). 2012: 586-592.
[7]王颖, 宋宗贤, 王东坡, 等. EH36钢焊接接头在超长寿命区间的疲劳性能[J]. 天津大学学报, 2013, 46(5): 453-457.
Wang Ying, Song Zongxian, Wang Dongpo, et al. Super-long life fatigue properties of EH36 steel welded joints[J]. Journal of Tianjin University, 2013, 46(5): 453-457.
[8]柳浩, 杨艳华. 正火工艺对EH40船板钢组织和性能的影响[J]. 热加工工艺, 2016, 45(16): 233-235.
Liu Hao, Yang Yanhua. Effect of normalizing process on microstructure and mechanical properties of EH40 steel for ship plate[J]. Hot Working Technology, 2016, 45(16): 233-235.
[9]唐家宏, 麻永林, 刘泽田, 等. 正火型DH36高强度船板钢的开发[J]. 金属热处理, 2015, 40(1): 144-146.
Tang Jiahong, Ma Yonglin, Liu Zetian, et al. Development of normalizing DH36 high strength hull plate steel[J]. Heat Treatment of Metals, 2015, 40(1): 144-146.
[10]李鑫磊, 杨春卫. 正火后控冷工艺在厚规格船板开发中的应用[J]. 钢铁, 2013, 48(5): 81-84.
Li Xinlei, Yang Chunwei. Application of controlled cooling process after normalizing in the development of heavy gauge ship plate[J]. Iron and Steel, 2013, 48(5): 81-84.

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