管螺纹的标注与管螺纹内径外径对照

管螺纹尺寸代号(约等于管的内径，单位：in）每英寸牙数n螺距p螺纹直径大径D、d螺纹直径小径D1、d1G1/16280.9077.7236.561G1/8280.9079.7288.566G1/4191.33713.15711.445G3/8191.33716.66214.95G1/2141.81420.95518.631G5/8141.81422.91120.587G3/4141.81426.44124.117G7/8141.81430.20127.877G1112.30933.24930.291G1-1/8112.30937.89734.939G1-1/4112.30941.9138.952G1-1/2112.30947.80344.845G1-3/4112.30953.74650.788G2112.30959.61456.656G2-1/4112.30965.7162.752G2-1/2112.30975.18472.226G2-3/4112.30981.53478.578G3112.30987.88484.926G3-1/2112.309100.3397.372G4112.309113.03110.072G5112.309138.43135.472G6112.309163.83160.872注：1in=25.4mm1、用螺纹密封的管螺纹其标记及各种螺纹的特征代号规定如下：Rc—圆锥内螺纹Rp—与圆锥外螺纹配合的圆柱内螺纹R—圆锥外螺纹标准规定将螺纹尺寸代号写在特征代号之后，若螺纹为械旋应再加写左旋代号LH，具体示例如下：圆锥内螺纹：Rc1/2左旋圆柱内螺纹：Rp1/2—LH圆柱内螺纹与圆锥外螺纹的配合：Rp2/R22、非螺纹密封的管螺纹标记如下：A级外螺纹：G1/2A内螺纹：G1/2左旋B级外螺纹：G1/2B—LH螺纹副：G1/2G1/2A管螺纹的标注与标准螺纹换算(螺压角为55度)