VIDEO & CENTER
The quality of the screw can be judged from the following aspects:
- Appearance inspection
Surface smoothness: The surface of high-quality screws should be smooth and flat, without burrs, cracks, pits and other defects.
Uniform color: the color should be consistent, no obvious color difference or spots.
Thread regularity: clear and uniform thread, no deformation, missing teeth, random buckle and other problems.
Second, material identification
Check the identification: regular screws usually have a material identification, you can preliminarily judge the material type through the identification.
Magnet detection: For iron screws, you can use magnet adsorption to determine its purity. If the adsorption force is strong, it may contain more impurities.
Hardness test: Use a hardness tester or a simple tool for hardness test, hardness in line with the standard screw quality is relatively good.
- Dimensional accuracy
Measuring diameter: Use a tool such as a caliper to measure the diameter of the screw and ensure that it conforms to the specified size range.
Length measurement: accurately measure the length of the screw, and the error should be within the allowable range.
Pitch detection: Check whether the pitch of the thread is uniform and consistent, in line with the standard requirements.
- Mechanical properties
Tensile strength: It can be tested by professional tensile testing machine to know whether the tensile strength of the screw meets the requirements.
Torque test: Use torque wrench to tighten the screw test to observe whether it will slip, break and so on under a certain torque.
- Corrosion resistance
Salt spray test: For corrosion-resistant materials such as stainless steel screws, salt spray test can be carried out to observe its corrosion resistance in a certain time.
Environmental simulation: Place the screw in the actual use of the environment for a period of time to observe whether it appears rust, corrosion and other phenomena.
- Brand and certification
Choose well-known brands: Well-known brands usually have more stringent quality control systems, and product quality is relatively more guaranteed.
Check the certification marks: such as ISO quality certification, industry standard certification, etc., these marks can be used as a reference for screw quality.
