GB/T 41157.4-2022Fasteners for nuclear power plants—Part 4: Nuts made of corrosion-resistant stainless steel (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" drafted.

This document is part 4 of GB/T 41157 "Fasteners for Nuclear Power Plants". GB/T 41157 has published the following parts.

--- Part 1: Alloy steel bolts, screws and studs;

--- Part 2: Carbon steel and alloy steel nuts;

--- Part 3: Stainless steel bolts, screws and studs;

--- Part 4: Stainless steel nuts;

--- Part 5: Acceptance inspection.

Introduction

Fasteners are widely used in the safety systems and equipment of nuclear power plants, and undertake functions such as pressure sealing, component connection and support and fixation.

Quantity and performance play an important role in nuclear power plant safety systems and equipment performing nuclear safety functions. However, in nuclear power plant construction and equipment manufacturing During the supervision process, it was found that there are weak links in the design, procurement, manufacture, installation and acceptance of nuclear power fasteners. GB/T 41157 "Nuclear Power Factory Fasteners" aims to standardize the technical requirements and test methods for fasteners used in nuclear power plants, and consists of the following five parts.

--- Part 1: Alloy steel bolts, screws and studs;

--- Part 2: Carbon steel and alloy steel nuts;

--- Part 3: Stainless steel bolts, screws and studs;

--- Part 4: Stainless steel nuts;

1 Scope

This document specifies the technical requirements, Test methods and marking and packaging at room temperature (10°C ~ 35°C).

Note 1.The product dimensions are specified in the corresponding product standards or drawings.

This document applies to grades 1, 2 and 3 stainless steel nuts.

a) manufactured from austenitic stainless steel (solution state), martensitic stainless steel or precipitation hardening stainless steel;

b) Ordinary threads complying with GB/T 192 and GB/T 196;

c) Coarse thread M5~M64, fine thread M8x1~M64x4;

d) Comply with the tolerances specified in GB/T 197 and GB/T 9145;

e) The diameter and pitch combination specified in GB/T 193;

f) of any shape. This document does not specify the following performance requirements.

--- Effective torque type nut locking performance (see GB/T 3098.9);

--- Solderability.

The 1st, 2nd and 3rd grade stainless steel nuts for other reactor type nuclear power plants can also refer to this document.

Note 2.The applicable maximum operating temperature for fasteners produced in accordance with this document is 370 °C. When the operating temperature exceeds 370°C, it is recommended that the user consult the relevant experts consult.

2 Normative references

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, dated citations documents, only the version corresponding to that date applies to this document; for undated references, the latest edition (including all amendments) applies to this document.

GB/T 196 Basic dimensions of common thread

GB/T 197 Ordinary thread tolerance

GB/T 228.1 Tensile Test of Metallic Materials Part 1: Test Method at Room Temperature

GB/T 230.1 Rockwell hardness test of metallic materials - Part 1: Test method

GB/T 231.1 Brinell hardness test for metallic materials - Part 1: Test method

GB/T 3098.15 Fasteners Mechanical Properties Stainless Steel Nuts

GB/T 3103.1 Fastener Tolerance Bolts, Screws, Studs and Nuts

GB/T 4340.1 Vickers Hardness Test for Metal Materials Part 1: Test Methods

GB/T 5276 Fastener bolts, screws, studs and nuts dimension code and marking

GB/T 6394 Metal Average Grain Size Determination Method

GB/T 16825.1 Inspection of static uniaxial testing machines Part 1: Inspection and calibration NB/T.20003.4 Non-destructive testing of nuclear island machinery in nuclear power plants - Part 4: Penetrant testing