GB/T 3765-2008 English PDF (GBT3765-2008)

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GB/T 3765-2008: 24-degree cone connectors -- Specification
GB/T 3765-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 21.060.60
J 15
Replacing GB/T 3765-1983
24° cone connectors - Specification
ISSUED ON: MAY 07, 2008
IMPLEMENTED ON: NOVEMBER 01, 2008
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Materials ... 7
5 Pressure-temperature requirements ... 8
6 Marks ... 11
7 Requirements for connected pipes ... 12
8 Wrench dimensions and tolerances ... 12
9 Structure and manufacturing ... 13
10 Performance and test requirements ... 15
11 Installation instructions ... 15
12 Procurement information ... 16
13 Marks ... 16
Annex A (normative) Type F threaded oil port and stud end dimensions ... 17
Annex B (normative) Test methods ... 21
Annex C (normative) Test record sheet ... 33
24° cone connectors - Specification
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)
3.1 connector; fitting
Sealed connection assemblies between pipes, between pipes and other equipment.
3.2 connection body
Parts that connect pipes and equipment through connecting nuts and 24° cones or
cone seals.
3.3 stud end thread
External threads connected to threaded ports.
3.4 maximum working pressure
The highest pressure at which a system or system part can operate stably.
4 Materials
4.1 Connection body
The material of the connection body shall be compatible with the transmission
medium and ensure an effective connection.
The connection body made of carbon steel shall meet the pressure-temperature
requirements specified in Chapter 5. For connection bodies made of other materials
such as stainless steel or copper alloy, the pressure-temperature value is specified by
the manufacturer.
4.2 Connecting nut
Unless otherwise agreed between the supplier and the purchaser, the connecting nut
used in conjunction with the carbon steel joint body shall be made of carbon steel;
the connecting nut used in conjunction with the stainless steel joint body shall be
made of stainless steel; the connecting nut used in conjunction with the copper alloy
joint body shall be made of copper alloy.
4.3 24° cone
24° cone material shall be compatible with the transmission medium. Guarantee a
valid connection.
Carbon steel 24° cones are used with carbon steel connection bodies and carbon steel
pipes. Stainless steel 24° cones are used with stainless steel connection bodies and
stainless-steel pipes. Copper 24° cones are used with copper connection bodies and
copper pipes. The combined use of different types of materials shall be determined
through negotiation between the supplier and the purchaser.
4.4 O-ring
If not otherwise specified, O-rings for petroleum-based hydraulic fluids and
complying with the pressure-temperature requirements of Clause 5 and Table 1 shall
be made of nitrile rubber (NBR). Its hardness shall be (90 ± 5) IRHD. Measure
according to GB/T 6031. Its appearance quality shall not be lower than the level N
requirements of GB/T 3452.2. For O-rings used outside the pressure-temperature
range specified in Chapter 5 or in non-petroleum-based hydraulic fluid systems,
other durometers or other materials may be used, but the fitting manufacturer shall
be consulted.
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.
5.2 Unless otherwise specified, connectors with elastomeric seals shall be given a
special operating temperature range for use in petroleum-based hydraulic fluid
systems. Its operating temperature range may be reduced, or it may not be suitable
for other fluids at all. Manufacturers can provide elastic seals that are suitable for
different mediums and can meet the temperature range requirements.
5.3 According to different pressure levels and service conditions, the 24° cone
connectors are divided into the following three series:
- LL: ultra-light load series;
- L: light load series;
- S: heavy load series.
mm.
8.2 The tolerance of the dimension S across the sides of the hexagon shall comply
with the requirements for Class B products in GB/T 3103.1. The diagonal dimension
of the hexagon shall not be less than 1.092S. The wrenching side length shall not be
less than 0.43S. If there is no other provision or mark, the hexagon shall be
chamfered by 10°~30°, the diameter of the chamfer shall be equal to the dimension S
of the opposite side of the hexagon. The tolerance of the chamfer diameter shall be
mm.
9 Structure and manufacturing
9.1 Appearance structure
The type and size of 24° cone connectors shall meet the requirements of
corresponding standards. Structural dimensions not specified in the standard are to
be determined by the manufacturer, but fluid resistance shall be minimized.
9.2 Size
The size specified in the standard refers to the finished product size including the
thickness of the coating or surface treatment layer. The tolerance of all unfilled
dimensions shall be ±0.4 mm. The circular runout tolerance of the 24° inner cone
seat at the 24° cone end to the pitch diameter of the outer thread shall be 0.25 mm.
The verticality tolerance of the pitch diameter of the stud end thread to the sealing
end face shall be 0.10 mm.
9.3 Channel tolerance
When the ...