GB/T 43232-2023Fasteners—Measurement method of axial stress by ultrasonic (English PDF)

Foreword

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

Introduction

The axial stress of the bolt is related to the reliability of the bolt connection and is an important parameter that needs to be controlled during bolt installation and service. The axial stress Too much force will cause the bolt to break, and too little axial stress will cause the bolt connection to loosen. Therefore, it is necessary to detect and measure the axial stress of the bolt connection. monitoring[3,4]. Commonly used bolt tightening axial force detection methods in the engineering field include torque method, angle method, strain gauge method, etc. [5,6]. Currently, ultrasound The method has also been intensively studied and increasingly used.

In 1953, Hughes from the University of Tennessee in the United States studied the acoustic elasticity of various homogeneous materials based on the finite deformation theory and revealed that the material According to the law that the propagation speed of ultrasonic longitudinal and transverse waves in materials is sensitive to stress, the acoustic elasticity theory of ultrasonic measurement of stress has been established [7]. Play with sound Based on the principle of stability, domestic and foreign scholars have conducted a lot of research on ultrasonic detection models and methods of bolt tightening stress [8-16]. Liu Zhenqing et al.

Based on the principle of acoustic elasticity, a bolt axial stress measurement model was established [8]. He Cunfu et al. studied the effects of temperature and torsional shear stress on bolt axial stress.

The influence rules of ultrasonic measurement and proposed correction scheme [9,10]. Xu Chunguang et al. conducted a model for jointly measuring bolt tightening stress with transverse and longitudinal waves. research [11,12,14]. Pan Qinxue et al. proposed an ultrasonic detection model for bolt fastening stress based on shape factors and material factors [13].

With the development of ultrasonic testing technology, the method of measuring bolt axial stress using ultrasonic method is increasingly widely used in various fields of the machinery industry.

1 Scope

This document specifies the principles, instrumentation, measurement, data processing and measurement reporting of ultrasonic measurement methods for axial stress in bolts, screws and studs.

This document is applicable to the measurement of axial stress of bolts, screws and studs (hereinafter referred to as bolts) during or after assembly, and their use in service Dynamic in-situ monitoring of axial stress in service state. Bolts to which this document applies.

a) Single wave. the nominal diameter is not less than 5mm, double wave. the nominal diameter is not less than 12mm;

b) The aspect ratio is not less than 3.1;

c) Performance level 8.8 and above;

d) Acoustically isotropic materials;

e) Axial stress range. (30%~90%)Rp0.2.

Note 1. For bolts with special structural types (such as short length, hollow, variable diameter) or geometric shapes, as well as performance levels below 8.8, please refer to this document.

Ultrasonic testing may not meet the accuracy requirements specified in this document.

Note 2. For situations outside the (30%~90%) Rp0.2 stress interval, the ultrasonic measurement specified in this document may not be achieved when referring to this document. Accuracy requirements.

2 Normative reference documents

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

GB/T 228.1 Tensile testing of metallic materials Part 1: Room temperature test method

GB/T 16823.3 Fastener torque-clamping force test

GB/T 16825.1 Inspection and calibration of static uniaxial testing machines for metallic materials Part 1: Tensile and/or compression testing machines Inspection and calibration of force measuring systems

GB/T 18852 Reference test blocks and methods for measuring sound beam characteristics of contact probes for non-destructive testing and ultrasonic testing

GB/T 20935.1 Electromagnetic ultrasonic testing methods for metallic materials Part 1: Guidelines for electromagnetic ultrasonic transducers

GB/T 38952 Non-destructive testing residual stress ultrasonic body wave testing method JJF (Mechanical) 1056 Calibration Specifications for Residual Stress Ultrasonic Detectors

3 Terms and definitions

The terms and definitions defined in GB/T 16823.3, GB/T 38952 and the following apply to this document.