GB/T 9125.2-2020Fasteners for steel pipe flange joints—Part 2: Class designated (English PDF)

Foreword

GB/T 9125 "Fasteners for steel pipe flange joints" is divided into two parts:

- Part 1: PN designated;

- Part 2: Class designated.

This is Part 2 of GB/T 9125.

This Part was drafted in accordance with the rules given in GB/T 1.1-2009.

This Part replaces part of GB/T 9125-2010 "Fasteners for pipe flange joints". Compared with GB/T 9125-2010, the main technical changes are as follows:

- Modified the scope statement (see Chapter 1 of this Edition; Chapter 1 of Edition 2010);

- Supplemented and improved the normative references (see Chapter 2 of this Edition; Chapter 2 of Edition 2010);

- Added the specifications of bolts and studs (see Table 1, Table 2 of this Edition);

- Deleted the content of equal length studs (see 3.2 of Edition 2010);

- Deleted the performance grades A2-80 and A4-80 of hexagonal head bolts and equal-length studs (see Table 1 and Table 2 of Edition 2010);

- Added material designations for full-thread studs and nuts (see Table 2 and Table 4 of this Edition);

- Added the requirements for fastener tolerances (see 3.4 of this Edition);

- Added length and mass of fasteners (see 3.5 of this Edition);

- Added manufacturing and heat treatment (see Chapter 5 of this Edition);

- Modified the provisions on surface treatment of fasteners (see 5.1.6 of this Edition; Chapter 5 of Edition 2010);

- Modified the provisions on inspection and testing (see Chapter 6 of this Edition; Chapter 6 and Chapter 7 of Edition 2010);

- Added Annex A "Length and mass of fasteners" (see Annex A of this Edition);

- Modified the contents of Class designated in the Annex A of Edition 2010 into Annex B (see Annex B of this Edition; Annex A of Edition 2010); […]

1 Scope

This Part of GB/T 9125 specifies the structural types, dimensions and tolerances, materials, manufacturing and heat treatment, inspection and acceptance, product quality certificates, marks and signs, protection and packaging requirements for Class designated fasteners for steel pipe flange joints.

This Part applies to fasteners for steel pipe flange connections (including hexagon head bolts, full-thread studs and nuts) specified in GB/T 9124.2 and GB/T 13402.

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 2, Fasteners -- Ends of parts with external thread

GB/T 90.1, Fasteners -- Acceptance inspection

GB/T 196, General purpose metric screw threads -- Basic dimensions

GB/T 197, General purpose metric screw threads -- Tolerances

GB/T 228.1, Metallic materials -- Tensile testing -- Part 1: Method of test at room temperature

GB/T 699, Quality carbon structure steels

GB/T 700, Carbon structural steels

GB/T 1220, Stainless steel rod

GB/T 1221, Heat-resistant steel bars

GB/T 3077, Alloy structure steels

GB/T 3098.1, Mechanical properties of fasteners -- Bolts, screws and studs

GB/T 3098.2, Mechanical properties of fasteners -- Nuts

3 Structural types, dimensions and tolerances

4 Materials

6 Inspection and acceptance

7 Product quality certificate

7.1 Each batch of fasteners produced in accordance with this Part shall be accompanied by a product quality certificate.

7.2 The product quality certificate shall include the following contents:

a) Manufacturer name and date of manufacture;

b) Official seal of the manufacturer's technical (quality) inspection department;

c) Signature of the quality inspector and inspection date;

d) Product name, specification, material designation and material standard or performance grade;

e) Chemical composition and mechanical properties;

f) Other inspection reports specified in the contract.

8 Marks and signs

8.1 The marks of fasteners shall comply with the following provisions:

a) Product name;

b) Reference to this Part: GB/T 9125.2;

c) Thread size and nominal length, no length marking for nuts;

d) Material designation or performance level;

e) Nut type code.

Example 1: The mark of a hexagonal head bolt with thread size M20, nominal length 100 mm and performance grade 8.8 is: Hexagonal head bolt GB/T 9125.2 M20×100 8.8. […]