Transactions of Materials and Heat Treatment

Title：Grain refinement forging technology of connecting rod for large marine diesel engine

Authors： Sun Changfen Hu Jinhua Wu Peng Yuan Zhiqiang Xu Jiuhai

Unit： Hudong Heavy Machinery Co. Ltd. Shanghai Dianji University CSSC Marine Power Components Co. Ltd.

KeyWords： connecting rod forging grain size grain refinement numerical simulation

ClassificationCode：TG316.2

year,vol(issue):pagenumber：2020,45(5):34-37

Abstract：

Through the method of forging process simulation and analysis, the numerical simulation was used to replace the physical test, which solved the problems encountered in the forging process, reduced the scrap rate, made the grain size of forging core meet the design requirements and improved the fatigue life of connecting rod. Then, the forging process of connecting rod was simulated by forging simulation software Forge, and it was forged with flat anvil and formed by two heating. Through the adjustment of forging ratio and initial forging temperature, the process optimization was studied. And the improved process is as follows: the initial forging temperature for the first heating is 1100 ℃, the forging ratio is about 1.29 in A zone, the forging ratios are about 1.38 in B, C and D zones, and the initial forging temperature for the second heating is 950 ℃ which is essentially different from the conventional initial forging temperatures of two heating that is above 1200 ℃, the forging ratio in A zone is about 1.35, the forging ratios in B, C and D zones are about 1.32. The core grain size of forgings at room temperature is about grade 8 when cooling to room temperature after forging. Finally, the design goal that the core grain size of connecting rod forged from grade 4 to more than grade 8 is achieved and is verified by the process experiment.

Funds：

工信部船用低速柴油机原理样机研制资助；上海市高原学科-机械工程学科资助（A1-5701-18-007-03）

孙常奋（1965-），男，工程硕士，高级工程师，E-mail：dt_SUN@126.com；通讯作者：胡金华（1972-），男，博士，副教授，E-mail：cae007@126.com

Reference：

[1]Sellars C M, Witeman J A. Recrystallization and grain growth in hot rolling[J]. Metal Science, 1978, (13):187-194.
[2]Yada H, Senuma T. Resistance to hot deformation of steel[J]. Journal of Japan Society of Technology Plasticity, 1988, (27):33-44.
[3]Karhausen K, Kopp R, De Souza M M. Numerical simulation method for designing thermomechanical treatment, illustrated by bar rolling[J]. Scandinavian Journal of Metallurgy, 1991, (20): 351-363.
[4]李梦飞, 张立文, 张驰, 等. 38MnVS6非调质钢大尺寸棒材往复热轧过程微观组织演化数值模拟[J]. 塑性工程学报, 2016, 23 (6):112-118.
Li M F, Zhang L W, Zhang C, et al. Numerical simulation of microstructure evolution during hot reversible rolling process of largesize 38MnVS6 nonquenched and tempered steel rod[J].Journal of Plasticity Engineering, 2016, 23 (6):112-118.
[5]李馨家, 崔振山, 冯超, 等. 核电封头-过渡锥体一体化成形全工艺过程多尺度模拟[J]. 塑性工程学报, 2016, 23 (6):1-7.
Li X J, Cui Z S, Feng C, et al. Multiscale simulation on the whole integrated forming process for nuclear pressure vessel head and over cone[J]. Journal of Plasticity Engineering, 2016, 23 (6):1-7.
[6]李雪, 宋现洲, 宋新双, 等. 大型连杆锻件锻造工艺优化[J]. 大型铸锻件, 2019, (2):16-17, 22.
Li X, Song X Z, Song X S, et al. Forging process optimization of large sized connecting rod forgings [J]. Heavy Casting and Forging, 2019, (2): 16-17, 22.
[7]张晓芳, 张西安, 王炎生, 等. WRF 法在大型连杆锻件上的应用[J]. 大型铸锻件, 2016, (2):56-57,59.
Zhang X F, Zhang X A, Wang Y S, et al. Application of WRF method on heavy connection rod forgings [J]. Heavy Casting and Forging, 2016, (2): 56-57,59.
[8]Murty S V S N，Sarkar A，Narayanan P R，et al． Development of processing maps and constitutive relationship for thermomechanical processing of aluminum alloy AA2219 [J]．Journal of Materials Engineering and Performance，2017，26(5): 2190-2203.
[9]Chu Y D，Li J S，Zhao F T，et al． Flow behavior and constitutive relationship for elevated temperature compressive deformation of a high Nb containing TiAl alloy with (α2+γ) microstructure[J]．Materials Letters，2018，(210): 58-61.
[10]Li H P，He L F，Zhao G Q，et al．Constitutive relationships of hot stamping boron steel B1500HS based on the modified Arrhenius and JohnsonCook model[J].Materials Science and Engineering A，2013，(580): 330-348.
[11]张施琦, 冯定, 张跃, 等. 新型超高强度热冲压用钢的热变形行为及本构关系[J]. 材料工程，2016，44（5）:15-21.
Zhang S Q，Feng D，Zhang Y，et al． Hot deformation behavior and constitutive model of advanced ultrahigh strength hot stamping steel[J]．Journal of Materials Engineering，2016，44(5): 15-21.
[12]康大韬，叶国斌．大型锻件材料与热处理[M]．北京:龙门书局，1998.
Kang D T, Ye G B. Materials and Heat Treatment for Large Forgings [M]. Beijing: Longmen Press, 1998.
[13]GB/T 6394—2017, 金属平均晶粒度测定方法 [S].
GB/T 6394—2017, Determination of estimating the average grain size of metal [S].

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