螺纹环规使用

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Sophia Yang

07.04.04

TESTING INSTRUCTIVE

Male Tapered Threads

Code:

Rev.0

TI-007-001

Sophia

07.04.04

1. Objective 目的

Provide detail information for every step about how to perform the test about the tapered male

rdize the actions of the inspectors and clarify the determining way in different

conditions of the test.

就如何检验锥形外螺纹提供详细的各步骤说明. 规范检验人员动作及阐明各种情形下的判断方法．

2. Scope 范围

It is applicable for all the male tapered threads such as NPT,BSPT etc.

适用于所有锥形外螺纹，比如ＮＰＴ，ＢＳＰＴ等．

3. Definitions 定义

3.1 Thread螺纹

There are two main types of threads used presently around the world, one being a normal

straight thread and the other is tapered thread. Tapered threads are used when pressure tight

joint are made on the threads. Straight thread is only otherwise. Tapered thread is also known as

conical angle of the tapered thread is 1˚47’. NPT and BSPT are tapered threads

mostly used whin the faucet industry.

目前世界上主要有两种螺纹．一种是平形螺纹，另一种是锥形螺纹．锥形螺纹主要用于压力密封连接上．而平形螺纹则用于其它方面．锥形螺纹锥度为1˚47’．NPT和ＢＳＰＴ是两种主要用于水龙头行业的锥形螺纹

NPT: National Pipe Tapered；The angle of thread is 60˚.美标管锥螺纹，牙形角60˚．

BSPT: British Standard Pipe Tapered;The angle of thread is 55˚．英标管锥螺纹，牙形角

55˚.

3.2 Ring gauge 环规

Thread ring gauge is the tool for an all-around checking about the male threads which with the

female threads.

螺纹环规是一个对外螺纹进行全面综合检查的一个工具．

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TESTING INSTRUCTIVE

Male Tapered Threads

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TI-007-001

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07.04.04

3.3 Accuracy class 精度等级

There are 3 accuracy classes for American Standard thread in inch unit. The class 2 is the most

wildly used one. The class 3 is only for exact industry. The class 1 is for the loose match, while

there is only one accuracy class for R in DIN.

对于美标的英制螺纹有三个精度等级．等级２应用的最广泛，等级３则一般用于精工，等级１则适用于非常松的允差配合．而ＤＩＮ标准的R螺纹则只有一个精度等级.

3.4 Standard 标准

The DIN R thread gauges are designed for Parallel / Tapered Match must be careful

to choose the right gauge marked with manufacturer and the clients should use the

gauge following the same standard.

对于ＤＩＮ标准的Ｒ螺纹量规是为柱／锥配合体系设计的，选择量具时请注意量具上应有ＤＩＮ标记．生产商和客户应当使用同一标准下的量规.

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Made By: Sophia Yang 07.04.04

TESTING INSTRUCTIVE

Checked:

Male Tapered Threads

Approved: Rev.0 Sophia 07.04.04

4. Tools 工具

4.1 Ring Gauge环规

First choose the correct matched ring gauge according to the thread standard and specification of

the product. Because different standards specify thread per inch, angle of thread, roots, crests,

truncations and many others differently.

首先根据产品螺纹的种类及规格选择匹配的环规．因为不同种类螺纹的牙数，牙形角，齿顶，齿跟等都不相同．

The ring gauge for tapered thread has three number 1 surface is the low limit and

the number 3 surface is the up limit. The number 2 surface is the base level.

检验锥形螺纹的环规有三个面．１号面是下限，３号面是上限．而２号面是基面．

Accuracy class: 2B (NPT)

精度等级: 2B (NPT)

Standard:

ISO7-2:2000/Nch1594-1-1979/DIN(BSPT); ANSI(NPT)

2

1

标准: ISO7-2:2000/Nch1594-1-1979/

(BSPT);ANSI(NPT)

Symbol of BSPT: R

BSPT 代号: R

3

Symbol of NPT: NPT / Z

NPT代号: NPT / Z

4.2 Calliper 卡尺

The specification of the calliper should cover the range of the thread length.

卡尺的量程应足够可测量螺纹长度

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DIN

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TESTING INSTRUCTIVE

Male Tapered Threads

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TI-007-001

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07.04.04

5. Instructions 步骤

Step 1 : Turn lightly the product into the ring gauge completely from the bottom. No

distortion.

步骤１：轻轻将产品从底部完全旋入环规内．不可挤压，不允许有变形.

Determine判断: You can't turn more even by small force (No distortion) .This status means

the matched threads already at the end position.

当你用很小的力（没有产生变形）不能继续旋进螺纹时则螺纹已经旋到底了

Step 2: Check the relative position of the thread of product to the surface of the gauge.

步骤２： 检查产品螺纹与环规各面的相对位置．

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TESTING INSTRUCTIVE

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Reject拒收

3

Thread of

product below

surface 3 产品螺纹低于３号面

3

Thread of

product and

surface 3 at

the same level

产品螺纹与３号面相平

Reject拒收

OK

3

1

1

Thread of

product is at

between

surface 1

and surface

3产品螺纹在１号面和３号面之间

Thread of

product and

surface 1 at the

same level

产品螺纹与１号面相平

OK

Reject拒收

1

Thread of

product over

surface 1 产品螺纹超出１号面

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TESTING INSTRUCTIVE

Male Tapered Threads

Code:

Rev.0

TI-007-001

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07.04.04

Determine判断: The position must be between 1# surface and 3# surface. The same level to

1# can be accepted too, but can’t be accepted if the same level to 3# surface.

产品螺纹的位置必须在环规的１号面和３号面之间．可以和１号面相平但不可与３号面相平

Step步骤 3 : Check the useful length ＂L" of the thread by calliper．

用卡尺测量螺纹的有效长度．

Useful length有效长度 L

Thread tail螺尾

Reference plane参考面

Specification

L Min

R3/8

8.8

R1/2

11.4

R3/4

12.7

R1

14.5

R1 1/4 R1 1/2

16.8 16.8

R2

21.1

Determine判断: The useful length of the thread should meet the requirements of the table

attached.

螺纹的有效长度需符合上表的要求．

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