齿轮轴锻坯是某大型国营企业的重要制件,需通过船级社检验认可。该坯件自由锻后需进行细化晶粒的正火处理,目的是使晶粒度及力学性能符合船舶制造规范的要求。起初,工艺为一次正火法,结果处理后发现明显混晶,最大晶粒度达不到船舶制造规范的要求,经常造成锻坯报废。为了消除严? Gear shaft forging billet is an important state-owned enterprise parts, to be approved by the classification society. After free forging, the blank needs to be normalized by grain refinement in order to make the grain size and mechanical properties meet the requirements of the ship’s manufacturing specifications. Initially, the process was a normalizing process, and the result was found to be markedly mixed and the maximum grain size did not meet the requirements of the ship’s manufacturing code, often resulting in scrap forging. In order to eliminate strict?