How to detect the quality of high-strength bolts?

High strength bolts are commonly used in structures that require high strength and heavy loads, such as large machines, bridges, and buildings. Therefore, detecting the quality of high-strength bolts is very important to ensure the safety and reliability of the structure. The following are several common detection methods.

1. Appearance inspection

Appearance inspection can be carried out using tools such as the naked eye or microscope, mainly to check whether there are obvious cracks, bubbles, scars, or pits on the surface of bolts. This method is relatively simple, but can only detect surface defects and cannot detect internal defects.

2. Magnetic particle inspection

Magnetic particle inspection is a method of spreading magnetic particles on the surface of bolts by applying a magnetic field, and detecting large and small cracks and defects using ultraviolet lamps and magnifying glasses. This method can detect surface and near ground surface defects, but its detection effect on internal defects is limited.

3. Ultrasonic testing

Ultrasonic testing can detect internal defects by sending sound waves to the interior of bolts and detecting waveform reflections. This method can detect internal defects in the neck and head areas of bolts, but its detection effect on deep defects is limited.

4. Tensile test

Tensile testing is a method of measuring the strain and deformation of high-strength bolts under tensile stress by placing them on a testing machine. The tensile strength, yield strength, and fracture strength of bolts can be determined through tensile testing, thereby evaluating the quality of bolts.

5. Hardness test

Hardness testing is a method of measuring the hardness of bolt materials using a hardness tester. The results of hardness test can provide information about the structure, mechanical properties and fatigue resistance of bolts, so as to evaluate the quality of bolts.

In summary, the quality inspection of high-strength bolts requires the comprehensive use of multiple methods to ensure their safety and reliability. Meanwhile, during the testing process, experienced testing institutions should be selected to ensure the accuracy and reliability of the testing results.