NPT美國(guó)標(biāo)準(zhǔn)的60度錐管螺紋

1、NPT：美國(guó)標(biāo)準(zhǔn)的60度錐管螺紋美制一般密封管螺紋的基本尺寸：尺寸代號(hào)牙數(shù)n螺距P牙型高度h基準(zhǔn)平面內(nèi)的基本直徑基準(zhǔn)距離L1裝配余量L3外螺紋小端面內(nèi)的基本小徑大徑d=D中徑d1=D2小徑d1=D1mm圈數(shù)mm圈數(shù)mmm1/16270.9410.7527.8947.1426.3894.324.06432.8226.1371/8270.9410.75210.2429.4898.7374.364.10232.8228.4811/4181.4111.12913.61612.48711.3584.105.78534.23310.9963/8181.4111.12917.05515.92614.7974

2、.326.09634.23314.4171/2141.8141.45121.22419.77218.3214.488.12835.44317.8133/4141.8141.45126.56925.11723.6664.758.61835.44323.127111.52.2091.76733.22831.46129.6944.6010.16036.62629.06011/411.52.2091.76741.98540.21838.4514.8310.66836.35037.78811/211.52.2091.76748.05446.28744.5204.8310.66836.35043.8532

3、11.52.2091.76760.09258.32556.5585.0111.06536.35055.86721/283.1752.54072.69970.15967.6195.4617.33526.35066.535383.1752.54088.60886.06883.5286.1319.46326.35062.31131/283.1752.540101.31698.77696.2366.5720.86026.35094.932483.1752.540113.973111.433108.8936.7521.43126.350107.554583.1752.540140.952138.4121

4、35.8727.5023.81226.350134.384683.1752.540167.792165.252162.7127.6624.32026.350161.191883.1752.540218.441215.901213.3618.5026.98826.350211.6731083.1752.540272.312269.772267.2329.6830.73426.350265.3111283.1752.540323.032320.492317.95210.8834.54426.350315.79314O.D.83.1752.540354.904352.364349.82412.503

5、9.68826.350347.34516O.D.83.1752.540405.784403.244400.70414.5046.03826.350397.82818O.D.83.1752.540456.565454.025451.48516.0050.80026.350448.31020O.D.83.1752.540507.246504.706502.16617.0053.97526.350498.79224O.D.83.1752.540608.608606.068603.52819.0060.32526.350599.758注：    可參考表中的最右邊一列數(shù)據(jù)選擇攻絲前

6、的麻花鉆直徑；               螺紋收尾長(zhǎng)度（V）為3.47 P；               O.D.是英文管子外徑（outside diameter）的縮寫(xiě)。標(biāo)記：美制一般密封管螺紋的完整標(biāo)記由螺紋特征代號(hào)，螺紋尺寸代號(hào)和旋向代號(hào)組成。左旋螺紋的旋向代號(hào)為L(zhǎng)H；右旋螺紋的旋向代號(hào)省略不標(biāo)。   

7、;   例如：1/8 NPT-LH,1/8表示螺紋尺寸，NPT為螺紋特征代號(hào)，LH表示左旋。      美制管螺紋的米制化方法：將管螺紋的原英寸尺寸乘以25.4就轉(zhuǎn)化為毫米尺寸。其他地方提供信息：油嘴說(shuō)明:油嘴，油管接頭。具體規(guī)格有： 3/8H-1/8PT/NPT 3/8H-1/4PT/NPT 3/8H-3/8PT/NPT 3/8H-1/2PT/NPT 3/8H-3/8AT 3/8H-1/2ATNPT外螺紋接頭實(shí)物是空心的,其公稱(chēng)規(guī)格的含義可以理解為該X英寸通徑的螺紋.美制管有規(guī)定的壁厚,故其外徑還包括壁

8、厚,由于螺紋有錐度,故不同位置的外徑是不同的,因此規(guī)定了一個(gè)基準(zhǔn)平面及尺寸.從標(biāo)準(zhǔn)中可以看到,1英寸的NPT螺紋外徑并不是25.4,而是33.228(基準(zhǔn)面).由于NPT管螺紋標(biāo)準(zhǔn)并未涉及管子外徑尺寸(僅有一個(gè)標(biāo)注),故只能以基準(zhǔn)面的尺寸按1:16的錐度推算其它位置的尺寸.每一位置的計(jì)算公式: 中徑=大徑-0.8P(螺距)小徑=大徑-1.6P(螺距)公式中的各參數(shù)均為同一位置.-1/8 10.3 （1分）1/4 13.7 （2分）3/8 17.1 （3分）1/2 21.3 （4分）3/4 26.71 33.41 1/4 42.21 1/2 48.32 60.32 1/2 73.03 88.92

9、/1 101.64 114.35 141.36 168.38 219.110 273.112 323.914 355.616 406.418 457.020 508.022 559.024 610.030 762.0為了便于對(duì)以上問(wèn)題的理解,附上美制管子螺紋與外徑的對(duì)照表.此表左邊為美制管子規(guī)格,右邊為管子外徑.-NPT是 National (American) Pipe Thread 的縮寫(xiě)，屬于美國(guó)標(biāo)準(zhǔn)的 60 度錐管螺紋，用于北美地區(qū)國(guó)家標(biāo)準(zhǔn)可查閱GB/T12716-1991 PT是 Pipe Thread 的縮寫(xiě)，是 55 度密封圓錐管螺紋，屬惠氏螺紋家族，多用于歐洲及英聯(lián)邦國(guó)家常用于水及煤氣管行業(yè)，錐度規(guī)定為 1:16 國(guó)家標(biāo)準(zhǔn)可查閱GB/T7306-2000-這些都是管螺紋，牙型角55度，說(shuō)白了就是水暖工常說(shuō)的4分兒，八分兒的。具體的