管螺纹 外螺纹大径 内螺纹小径 R18-28 9.728 8.566 R14-19 13.157 11.445 R38-19 16.663 14.951 R12-14 20.956 18.632 (R58-14) 22.912 20.588 R34-14 26.442 24.119 R1-11 33.250 30.2