下文中NECK和HUB分别指哪里? Ferritic steel flanges confirming to ASME B16.5 and B 16.47 and standard Long Weld Necks that have a neck outside diameter not exceeding the hub diameter specified in ASME B16.5 are exempt from impact testing at temperature not colder than -20F. 主要是不清楚上面的neck outside diameter 和hub diameter分别怎么表达,查阅ASMEB16.5知道hub diameter是颈直径,那neck outside diameter叫什么呢?叫颈外径?不确定,而且具体是指哪个尺寸? 盖德的高手请教啦! 查看更多1个回答 . 3人已关注