1、管螺纹类别及说明 1、用螺纹密封的管螺纹：（1）：圆柱内螺纹 Rp（2）：圆锥内螺纹 Rc（3）：圆锥外螺纹 R 牙形角：55 圆锥锥度：1:16 标注：Rc1/2/Rp1/2-LH（左旋，右旋不标）其他标注方法：ZG1/2、PT1/2（不分内外螺纹）尺寸代号每英寸牙数基面上的基本直径基准距离有效螺纹长度大径（基准直径）中径小径1/8289.7289.1478.56646.51/41913.15712.30111.4456.09.73/81916.66215.80614.956.410.11/21420.95519.79318.6318.213.23/41426.44125.27924.117
2、9.514.511133.24931.7730.29110.416.811/41141.9140.43138.95212.719.111/21147.80346.32444.84512.719.12、非螺纹密封的圆柱管螺纹牙形角：55标注：G1/2-LH（左旋，右旋不标）尺寸代号每英寸牙数大径中径小径1/8289.7289.1478.5661/41913.15712.30111.4453/81916.66215.80614.951/21420.95519.79318.6313/41426.44125.27924.11711133.24931.7730.29111/41141.9140.4313
3、8.95211/21147.80346.32444.8453、60圆锥管螺纹牙形角：60标注：Z1/2 其他标注方法：NPT1/2-LH（左旋，右旋不标）锥度：1:16尺寸代号每英寸牙数基面上的基本直径基准距离装配余量大径（基准直径）中径小径1/82710.2429.4898.7364.0122.8221/41813.61612.48711.3585.7864.2343/81817.05515.92614.7976.0964.2341/21421.22319.77218.3218.1285.4433/41426.56825.11723.6668.6115.443111.533.22831.46129.69410.1606.62711/411.541.8540.21838.45110.6686.62711/211.548.05446.28744.52010.6686.627注：内外螺纹的有效螺纹长度应不小于基准距离加装配余量之和。
