3A是卫生管件标准,(美标Dn).3A是the 3-A sanitary institute 的缩写,按照ASTM A270 “specification for seamless and welded austenitic steel sanitary tubing "执行的.替你找来个管道的国家标准。
3A是卫生管件标准,(美标Dn).3A是the 3-A sanitary institute 的缩写,按照ASTM A270 “specification for seamless and welded austenitic steel sanitary tubing "执行的.替你找来个管道的国家标准。