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多年来,40CrNiMoA、30CrMnSiA、38CrA、38CrMoAl及30CrMnSiNi_2A五种航空用结构钢奥氏体本质晶粒度一直采用氧化法检验。由于这种检验方法较难掌握,因此在检验中可能造成误判,并引起分歧。根据冶军字第977号文件规定要求,从1978年7月开始,对于这五种航空用结构钢奥氏体本质晶粒度的检验方法,由氧化法改为晶粒边界直接腐蚀法。从此以后,钢材晶粒度合格率大幅度下降,平均合格率仅为78%左右,严重地影响了军工产品生产任务的完成。
Over the years, 40CrNiMoA, 30CrMnSiA, 38CrA, 38CrMoAl and 30CrMnSiNi_2A five structural steel aviation austenite grain size has been used oxidation test. Because of this test method is more difficult to grasp, so in the test may cause miscarriage of justice and cause disagreements. According to Ye Jun Zi No. 977 document requirements, from July 1978 onwards, for the five aviation structural steel austenitic grain size of the test method, from oxidation to the grain boundary direct corrosion method. Since then, the passing rate of grain size of steel dropped significantly, with an average passing rate of only about 78%, seriously affecting the completion of military production tasks.