"90°ELBOW 3/4"NPT - STOCKHAM NO.601 - BLACK MALLEABLE IRON CLASS 150, ASTM A197, ANSI B16.3 & ANSI B1.20.1 "3 w4 M! c. A ~3 f
1.STOCKHAM NO.601 ' z3 F7 t; w7 E. A) ~6 f2.BLACK MALLEABLE IRON CLASS 150 1 L1 a8 c) u% q0 G) m q; q1 @% S3.后面的三个标准 ) _# p' i2 g8 u R6 ^分别是什么意思?