M10 Square Welded Nut

Quality control

The core of quality control for M10 Square Welded Nut lies in ensuring that the physical properties of the nut itself meet the standards, and that it can form a strong and reliable welding connection with the metal sheet.

【1】Follow the standard

The first step in quality control is to comply with relevant standards. The M10 Square Welded Nut mainly follows the DIN 928 standard and the domestic automotive industry standard QC/T 863-2011.

【2】Quality control of raw materials

（1）Chemical composition analysis: The key to welding performance lies in the carbon content, which must be controlled below 0.25%. The commonly used material is low-carbon steel.

（2）Surface quality inspection: Check whether there are any cracks, folds or other defects on the surface of the raw materials to ensure the smooth progress of the subsequent cold heading process.

【3】Production process quality control

（1）Cold heading forming: It is necessary to ensure that the key dimensions such as the width and height of the opposite sides of the M10 nut comply with the requirements of the drawings and the DIN 928 standard. In particular, the consistency of the height, shape and distribution position of the four welding protrusions at the bottom must be guaranteed.

（2）Tapping processing: 100% inspection of the threads of each M10 Square Welded Nut  is conducted using gauge blocks to ensure they meet the 6H precision grade requirements.

（3）Heat treatment: To meet the requirements of high-strength grades such as 8 or 10, quenching and tempering processes must be carried out to enable the nuts to achieve the desired strength.

【4】Final product inspection

（1）Appearance and size inspection: Through visual inspection or automated image screening, defective products with surface cracks, burrs, rust, etc. are eliminated. Key dimensions are inspected using tools such as calipers and micrometers to ensure they are within the tolerance range.

（2）Mechanical performance test: The M10 Square Welded Nut must be able to withstand the guaranteed load specified by the standard without causing the thread to disengage or break.

（3）Hardness test: The hardness is measured using a Rockwell or Vickers hardness tester.

（4）Surface treatment inspection: For surface treatments such as galvanizing and Dacromet, the thickness of the coating needs to be tested, and salt spray tests should be conducted regularly.