Manufacturing of ultra-large plate forgings by unfolding and flattening of thick cylinders

Abstract

Ultra-large plate forgings are foundation of heavy machinery, but many parts of the type cannot be made by conventional technologies due to the characters of extreme manufacturing in terms of size and quality requirements. This paper introduced a systematically method called cylinder unfolding method (CUM) for producing large plate forgings, by using a serial of operations including “splitting”, “unfolding”, and “flattening” of a thick cylinder obtained from saddle forging. The technological route of CUM was presented in detail with an example of plate forging with the horizontal sizes of 6100 mm and thickness of 300 mm. The deformation features of saddle forging for fabricating transitional cylinders were analyzed, and then the subsequent handling steps including splitting, unfolding and flattening of the cylinder, as well as the auxiliary processing, were addressed. The practice proved that CUM can provide an efficient way for manufacturing ultra-large plate forgings and meet the strict requirements in geometry and mechanical performance, without highly increasing the investments of forming equipment and tooling.

摘要

超大型平板锻件是重型机械工业的基础,但由于其在尺寸和质量要求方面具有极限制造的特点, 许多类型的零件无法采用传统方法制造。本文系统介绍了一种称为筒体展开法(CUM)的方法,可以通 过对马杠扩孔得到的过渡厚壁圆筒进行劈开、展开和压平等一系列操作,实现大型板锻件生产。以水 平尺寸6100 mm、厚度300 mm 的板锻件为例,详细介绍了CUM 的工艺路线,分析了圆筒马杠扩孔 过程的变形特点,介绍了筒体劈开、展开与展平等后续处理步骤以及辅助工序。生产实践证明,CUM 提供了一种有效的超大型平板锻件生产方法,可在无需增加设备和模具投资的同时,满足制件几何和 机械性能的要求。