Standard No.:	GB/T 9125.2-2020
English Name:	Fasteners for steel pipe flange joints—Part 2:Class designated
Chinese Name:	钢制管法兰连接用紧固件 第2部分：Class系列
Chinese Classification:	J15    Pipeline fittings
Professional Classification:	GB    National Standard
ICS Classification:	23.040.60 23.040.60    Flanges, couplings and joints 23.040.60
Issued by:	SAMR, SAC
Issued on:	2020-07-21
Implemented on:	2021-2-1
Status:	valid
Superseding:	GB/T 9125-2010 Fasteners for pipe flange joints
Language:	English
File Format:	PDF
Word Count:	12000 words
Price(USD):	400.0
Delivery:	via email in 1 business day

1 Scope This part of GB/T 9125 specifies the structural style, dimension and tolerance, material, manufacturing and heat treatment, inspection and acceptance, product quality certificate, marking and labeling, protection and packaging requirements of fasteners for class designated steel pipe flange joints. This part is applicable to fasteners for steel pipe flange joints (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 bars 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 GB/T 3098.6 Mechanical properties of fasteners - Stainless steel bolts, screws and studs GB/T 3098.15 Mechanical properties of fasteners - Stainless steel nuts GB/T 3103.1 Tolerances for fasteners - Bolts, screws, studs and nuts GB/T 5276 Fasteners - bolts, screws, studs and nuts - Symbols and designations of dimensions GB/T 5779.1 Surface discontinuities of fasteners on bolts, screws and studs for general requirements GB/T 5779.2 Fasteners - Surface discontinuities - Nuts GB/T 5782 Hexagon head bolts GB/T 5785 Hexagon head bolts - Fine pitch thread 3 Structural style, dimension and tolerance 3.1 Hexagon head bolt 3.1.1 The structural style of hexagon head bolt is detailed in Figure 1, and dimension codes and markings shall meet the requirements of GB/T 5276.

Foreword II 1 Scope 2 Normative references 3 Structural style, dimension and tolerance 3.1 Hexagon head bolt 3.2 Full-thread stud 3.3 Hexagon nut 3.4 Tolerance 3.5 Length and mass 4 Materials 4.1 General requirements 4.2 Technical requirements 5 Manufacturing and heat treatment 5.1 Manufacturing 5.2 Heat treatment 6 Inspection and acceptance 6.1 Inspection 6.2 Acceptance 7 Product quality certificate 8 Marking and labeling 9 Protection and packaging Annex A (Informative) Length and mass of fasteners Annex B (Informative) Calculation of length of fasteners Annex C (Informative) Classification of strength of fastener material