A.1/4 B.1/2 C.1 D.2
A.nb>4.0,ns>3.0 B.nb>3.0,ns>1.6 C.nb>3.0,ns>4.0 D.nb>1.6,ns>3.0
A.ASME規(guī)范 B.JIS規(guī)范 C.BS規(guī)范 D.AD規(guī)范