GB/T 3765-200824° cone connectors - Specification (English PDF)

Foreword

This Standard is one of a series of standards for 24° cone connectors.

This Standard is a revision to GB/T 3765-1983 "Specification for bite type tube fittings". The main revisions are as follows.

-- Change the English name of the standard;

-- Add the terms and definitions;

-- Modify the material requirements for parts. Delete the hardness requirements for parts;

-- Add the pressure-temperature requirements;

-- Change the connector series from E, G and J to LL, L and S series. Adjust the pipe outer diameter dimension series. Modify the relevant dimensions;

-- Add types F, E and B threaded stud ends. Add 55° non-sealed pipe thread (G), 55° sealed pipe thread (R) and 60° sealed pipe thread (NPT) to the stud end threads. Delete the original Metric tapered thread (ZM) in the standard;

-- Add marking methods and requirements for connected pipes;

-- Modify the relevant content of wrench size and tolerance, structure and manufacturing. Add the requirements for appearance structure and manufacturing quality;

-- Delete the inspection rules. Add the performance requirements and test methods for connectors;

-- Delete the relevant content of "Packaging and marks". Add the relevant requirements for installation instructions, procurement information and signs;

-- Revise Annex A "Instructions for assembly and use of bite type tube fittings" of GB/T 3765-1983 to Annex A "Type F threaded oil port and stud end dimensions" of this Standard. Add Annex B "Test methods" and Annex C "Test record sheet".

Annex A, Annex B and Annex C of this Standard are all normative. This Standard replaces GB/T 3765-1983 from the date of implementation.

1 Scope

This document specifies the material, pressure-temperature requirements, marking methods, connected pipe requirements, wrenching dimensions and tolerances, structure and manufacturing, performance and test requirements, installation instructions, procurement information, marks and other technical requirements for 24° cone connectors.

This Standard applies to hydraulic fluid transmission and general-purpose piping systems with a pipe outer diameter of 4 mm ~ 42 mm and a maximum working pressure of 10MPa to 63MPa.

NOTE 1: In newly designed hydraulic fluid power systems, Type F threaded stud ends shall be used.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 3, Run-outs, undercuts and chamfers for general purpose metric screw threads (GB/T 3-1997, eqv ISO 4755:1983; eqv ISO 3508:1976)

GB/T 193, General purpose metric screw threads - General plan (GB/T 193-2003, ISO 261:1998, ISO general purpose metrics screw threads - General plan, MOD)

GB/T197, General purpose metric screw threads - Tolerances (GB/T 197-2003, ISO 965-1:1998, ISO general purpose metric screw threads - Tolerances - Part 1. Principles and basic data, MOD)

GB/T 230.1, Metallic materials - Rockwell hardness test - Part 1: Test method (GB/T 230.1-2004, ISO 6508-1:1999, MOD)

GB/T 3103.1, Tolerances for fasteners - Bolts, screws, studs and nuts (GB/T 3103.1-2002, idt ISO 4759-1:2000)

GB/T 3141, Industrial liquid lubricants - ISO viscosity classification (GB/T 3141-1994, eqv ISO 3448:1992)

3 Terms and definitions

For the purposes of this document, the terms and definitions defined in GB/T 17446 as well as the followings apply.

4 Materials

4.3 24° cone 24° cone material shall be compatible with the transmission medium. Guarantee a valid connection.

5 Pressure-temperature requirements

5.1 Carbon steel pipe connectors conforming to the standard for 24° cone connectors shall be able to withstand the working pressure specified in Table 1 and Table 2 when the medium temperature is in the range of -40°C to +120°C. The wall thickness of the 24° cone-seal welded pipe under different working pressures shall meet the requirements in Table 3.

6 Marks

7 Requirements for connected pipes

The carbon steel pipes to be connected shall be low carbon steel normalized (NBK) seamless steel pipes that comply with the provisions of GB/T 3639.

8 Wrench dimensions and tolerances

8.1 When the forged wrench dimension across sides is less than or equal to 24 mm, the limit deviation is mm. When it is greater than 24 mm, the limit deviation is Galvanized.

9 Structure and manufacturing