PN 系列钢制管法兰检测
PNS 1423-1996锻合金钢.标准淬透性(H)系列和淬硬和回火至指定机械性能
This Standard specifies requirements for wrought alloy steels intended for general engineering purposes and is applicable to hot-rolled or cold-finished bars for machining, blooms, billets and slabs for forgings, and forgings.