锻压技术

大型船用柴油机连杆晶粒细化锻造工艺

英文标题：Grain refinement forging technology of connecting rod for large marine diesel engine

作者：孙常奋胡金华吴鹏袁志强许久海

关键词：连杆锻造晶粒度晶粒细化数值模拟

分类号：TG316.2

出版年,卷(期):页码：2020,45(5):34-37

摘要：

通过锻造工艺仿真分析的方法，以数值模拟来代替实物试验，解决了锻压过程中遇到的问题，降低了报废率，使锻件心部晶粒度达到设计要求，从而提高了连杆的疲劳寿命。采用锻造模拟软件Forge，对连杆锻造工艺进行数值模拟研究。采用平砧锻造，两火成形。通过对锻造比及始锻温度的调整，进行工艺优化研究。改进后的工艺为：第1火始锻温度为1100 ℃，A区锻造比约为1.29，B、C、D区锻造比约为1.38；第2火始锻温度为950 ℃，这与常规的两火始锻温度均在1200 ℃以上有着本质的区别，A区锻造比约为1.35，B、C、D区锻造比约为1.32。锻后冷却至室温，锻件室温心部晶粒度约为8级。最终，实现了连杆锻件心部晶粒度由4级细化到8级以上的设计目标，并用工艺试验进行了验证。

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.

基金项目：

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

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