GB /T 27944 - 2011 Dryseal pipe threads with the thread angle of 60 degrees

设计牙型

螺纹牙型的左、右牙侧角相等，牙型角的角平分钱垂直于螺纹轴线。圆锥螺纹的锥度为1 : 16。牙型尺寸应符合表中的规定。

圆柱内螺纹（ NPSF 和 NPSI ）牙型：

圆锥螺纹（NPTF 和 PTF-SAE SHORT）牙型：

干密封管螺纹的牙型尺寸

牙数 n	螺距 P/mm	原始三角形高度 H*/mm	削平高度 f		牙高 h
牙数 n	螺距 P/mm	原始三角形高度 H*/mm	公式	mm	公式	mm
27	0.941	0.815	0.094 P	0.089	0.678 P	0.637
18	1.411	1.222	0.078 P	0.109	0.710 P	1.004
14	1.814	1.571	0.060 P	0.109	0.746 P	1.353
11.5	2.209	1.913	0.060 P	0.132	0.746 P	1.649
8	3.175	2.750	0.055 P	0.175	0.756 P	2.400

注：圆锥管螺纹的 H 精确公式为 0.865 743P，与圆柱管螺纹 0.866 025P 间的差异可以忽略。
* H = 0.866 025P.

螺蚊种类及其适用场合

为提高螺纹密封连接的可靠性和安装性，允许在干密封螺纹副内添加合适的密封介质．但 2 级标准圆锥管螺纹（ NPTF）除外。

种类	代号	用途
标准圆锥管螺纹	NPTF	适用于各种场合。在强度和密封住方面，优于其他干密封螺纹。对硬脆位材料的薄壁管件，可以减少装配破坏的发生。
短型圆锥管螺纹	PTF-SAE SHORT	用于因管件空间或壁厚条件限制而无法采用标准圆锥管螺纹的场合。也可用于节省材料场合。
燃料圆柱内螺纹	NPSF	加工较为经济，但密封性能不如圆锥管螺纹。一般用于软性或延展性好的材质管件上。也可用于厚壁的硬脆性材料管件上。
大直径圆柱内螺纹	NPSI	加工性和密封性与燃料圆柱内螺纹相同。其直径比燃料圆柱内螺纹的大。在四种干密封管螺纹中，其旋合长度最长。用于厚壁的硬脆性材料管件，或者其他膨胀性小的管件上。

内、外螺纹组合

干密封内、外螺纹组合

外螺纹	内螺纹
标准圆锥外螺纹（NPTF）	标准圆锥内螺纹（NPTF）短型圆锥内螺纹（PTF-SAE SHORT）燃料圆柱内螺纹（NPSF）大直径圆柱内螺纹（NPSI）^*
短型圆锥内螺纹（PTF-SAE SHORT）	大直径圆柱内螺纹（NPSI）标准圆锥内螺纹（NPTF）

      注1 ：短型圆锥内、外螺纹（PTF-SAE SHORT）间不允许形成组合。
          注2 ：对不允许使用螺纹密封介质杨合，优先选用 2 级标准圆锥管螺纹（NPTF）组合。
          * 这两种组合使用不多．

螺纹基本尺寸

圆柱内螺纹（ NPSF 和NPSI）的直径基本尺寸与圆锥管螺纹基准平面内的直径相同。

圆锥管螺纹基本尺寸

螺纹尺寸代号	牙数 n	螺距 P/mm	牙型高度 h/mm	基准平面内的基本直径/mm			基准距离 L₁		装配余量 L₃		外螺纹有效螺纹长度^a L₂
螺纹尺寸代号	牙数 n	螺距 P/mm	牙型高度 h/mm	大径 D、d	中径 D₂、d₂	小径 D₁、d₁	mm	圈数	mm	圈数	mm	圈数
1/16	27	0.941	0.637	7.779	7.142	6.505	4.064	4.32	2.822	3	6.632	7.05
1/8	27	0.941	0.637	10.126	9.489	8.852	4.102	4.36	2.822	3	6.703	7.12
1/4	18	1.411	1.004	13.491	12.487	11.483	5.786	4.10	4.234	3	10.206	7.23
3/8	18	1.411	1.004	16.930	15.926	14.922	6.096	4.32	4.234	3	10.358	7.34
1/2	14	1.814	1.353	21.125	19.772	18.419	8.128	4.48	5.443	3	13.556	7.47
3/4	14	1.814	1.353	26.470	25.117	23.946	8.611	4.75	5.443	3	13.861	7.64
1	11.5	2.209	1.649	33.110	31.461	29.812	10.160	4.60	6.627	3	17.343	7.85
1 1/4	11.5	2.209	1.649	41.867	40.218	38.569	10.668	4.83	6.627	3	17.953	8.13
1 1/2	11.5	2.209	1.649	47.936	46.287	44.638	10.668	4.83	6.627	3	18.377	8.32
2	11.5	2.209	1.649	59.974	58.325	56.676	11.074	5.01	6.627	3	19.215	8.70
2 1/2	8	3.175	2.400	72.559	70.159	67.759	17.323	5.46	9.525	3	28.893	9.10
3	8	3.175	2.400	88.468	86.068	83.668	19.456	6.13	9.525	3	30.480	9.60

注：螺纹收尾长度 V 为 3.47P，肩距长度约为 2P。
a. 此列是 L₂ 环规的厚度尺寸。

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General purpose metric screw threads - Tolerances

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The blank diameters for rolling general purpose metric screw threads

GB /T 12716 - 2011

GB /T 24425.5 - 2009

Internal thread for wire thread inserts

GB /T 13576.1 - 2008

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GB /T 1415 - 2008

Metric threads where pressure-tight joints are made on the threads

GB /T 15756 - 2008

General purpose metric screw threads - Limits of sizes

GB /T 20670 - 2006

Unified screw threads - General plan

GB /T 5796.1 - 2005

Trapezoidal screw threads - Part 1: Profiles

GB /T 1414 - 2003

General purpose metric screw threads - The plan for pipe systems

GB /T 192 - 2003

General purpose metric screw threads-Basic profile（ISO 68-1:1998, MOD）

GB /T 196 - 2003

General purpose metric screw threads - Basic dimenslons

GB /T 2516 - 2003

General purpose metric screw threads - Limit deviations

GB /T 9144 - 2003

General purpose metric screw threads - Preferable plan

GB /T 9145 - 2003

General purpose metric screw threads - Limits of sizes for the screw threads of medium quality and preferable plan

GB /T 9146 - 2003

General purpose metric screw threads - Limits of sizes for the screw threads of coarse quality and preferable plan

GB /T 5280 - 2002

Tapping screws thread

GB /T 7307 - 2001

Pipe Threads with 55 Degree Thread Angle where Pressure-Tight Joints are not Made on the Threads

GB /T 7306.1 - 2000

Pipe threads with 55 degree thread angle where pressure-tight joints are made on the threads一 Parallel internal and taper external threads（eqv ISO 7-1:1994）

GB /T 7306.2 - 2000

Pipe threads with 55 degree thread angle where pressure-tight joints are made on the threads一 Taper internal and external threads（eqv ISO 7-1:1994）

GB /T 1181 - 1998

The interference-fit threads

GB /T 3 - 1997

Run-outs, undercuts and chamfers for general purpose metric screw threads (ISO 3508:1976 / ISO 4755:1983)

GB 1167 - 1996

The threads for transition fit

GB 7306 - 1987

Pipe threads where pressure-tight joints are made on the threads

GB /T 6559 - 1986

Screws thread shanks for thread forming screw-Metric coarse thread series

GB /T 922 - 1986

Specification for wood screws

IFI 502 - 1982

Metric triangle lock with thread end

IFI 502 - 1982

Metric Self-tapping Thread End

DIN 3858 - 2005

Whitworth pipe threads for pipe unions

DIN 7505 - 1986

Plastic threads

DIN 7970 - 1984

Threads and thread ends for tapping screws

DIN 103 - 1 - 1977

ISO - Metric Trapezoidal Screw Threads

DIN 7998 - 1975

Thread and thread ends for wood screws

DIN 2510-2 - 1971

Bolted Connections with Reduced Shank; Metric Thread with Large Clearence, Nominal Dimensions and Limits

ISO 3353-1 - 2020

Aerospace - Lead and runout threads - Part 1: Rolled external threads

ISO 2901 - 2016

ISO metric trapezoidal screw threads - Basic and design profiles

ISO 965-1 - 2013

ISO general purpose metric screw threads - Tolerances - Part 1: Principles and basic data

ISO 888 - 2012

Fasteners─Bolts,screws and studs─Nominal lengths and thread lengths

ISO 725 - 2009

ISO inch screw threads─Basic dimensions

ISO 228-1 - 2000

Pipe threads where pressure-tight joints are not made on the threads

ISO 1478 - 1999

Tapping Screws Thread

ISO 261 - 1998

ISO general purpose metric screw threads - General plan

ISO 262 - 1998

ISO general purpose metric screw threads — Selected sizes for screws, bolts and nuts

ISO 965-2 - 1998

Limits of sizes for general purpose external and internal screw threads

ISO 965-3 - 1998

Deviations for constructional screw threads

ISO 724 - 1993

ISO general-purpose metric screw threads─Basic dimensions

JIS B 1125 (1) - 2015

Tapping Screw Threads and Ends

JIS B 0251 - 2008

Limit gauges for metric screw threads

JIS B 1125 (1) - 2003

Tapping screw threads and ends

JIS B 0209 - 1997

Limits of sizes and tolerances for metric coarse screw threads

JIS B 1125 (1) - 1995

Tapping Screw Threads and Ends

JB /T 10971 - 2010

Locking Thread with 30° wedge ramp

ASME/ANSI B 18.6.3 (T40) - 2013

Dimensions of Threads and Points for Type AB and Type ABR Thread-forming Screws

ASME/ANSI B 18.6.3 (T41) - 2013

Dimensions of Threads and Points for Type B and BP Thread-Forming Tapping Screws

ASME/ANSI B 18.6.3 (T42) - 2013

Dimensions of Threads and Points for Type A Thread-Forming Tapping Screws

ASME/ANSI B 18.6.3 (T46) - 2013

Thread Lengths for Type A, AB, B, BF, BP and BT Tapping Screws

ASME/ANSI B 18.6.3 (T47) - 2013

Thread Lengths for Type C, D, F, G, T and TRS Tapping Screws

ASME/ANSI B 18.2.1 - 2010

Lag screw threads

ASME/ANSI B 18.6.3 - 2010

AB self-tapping teeth

ASME/ANSI B 18.6.3 - 2010

self-tapping teeth-B

ASME/ANSI B 18.6.3 - 2010

Self-tapping teeth-BF

ASME/ANSI B 18.6.3 - 2010

Triangle lock self-tapping teeth--D、F、G

ASME/ANSI B 18.6.3 - 2010

ASME/ANSI B 18.31.3 - 2009

Threaded rods(inch series) (A307, F1554, A193, CRES,F593,F468)

ASME/ANSI B 18.6.1 - 1997

Wood thread

ASME/ANSI B 18.6.1 - 1981

Wood thread

ASME/ANSI B 18.6.1 - 1981 (R2016)

Thread and body dimeters for wood screws

EN 60423 - 2007

EN 10226-1 - 2004

Pipe threads where pressure tight joints are made on the threads - Part 1 : Taper external threads and parallel internal threads - Dimensions, tolerances and designation