By Matt Xia | 04 January 2026 | 0 Comments
How to judge the quality of welding blade
After welding, the carbide-tipped cutting tools must be carefully inspected to assess quality and identify the causes of defects. Before inspection, the carbide tips should be sandblasted or gently ground to remove any adhering solder and impurities, and then cleaned with kerosene. The specific inspection items and requirements are as follows:
I. Inspection of weld strength: Grind the back of the cutting tool with a green silicon carbide grinding wheel and observe the thickness of the solder layer, which should be controlled to within 0.15 mm. There should be no pores or insufficient solder on the supporting surface of the blade. The length of unfilled welds should not exceed 10% of the total weld length. If pores are present, the blade may detach during cutting.
II. Inspection of blade position in the tool holder: If the blade is misaligned or sagging beyond technical specifications, it needs to be re-welded.
III. Inspection of welding strength: Tap the blade with a wooden hammer or copper hammer with moderate force, or strike the tool shank forcefully with an iron hammer. The blade is considered acceptable if it does not detach from the tool holder. Welding strength can be inspected using a sampling method; individual inspection of each tool is not necessary.
IV. Inspection of blade flatness: If there are noticeable dents on the blade surface, it indicates that the blade has been overheated and deformed. The blade should be removed and a new blade re-welded.
V. Inspection for cracks: If cracks are present in the cleaned blade, kerosene will seep into the cracks, appearing as black lines, which can be observed with the naked eye or with the aid of a 10-40x magnifying glass.
In addition, a color penetrant inspection method can be used: Use a solution composed of 65% kerosene, 30% transformer oil, and 5% turpentine, with a small amount of Sudan red added. Immerse the cutting tool blade in this solution for 10-15 minutes, remove it, wash it with clean water, apply a layer of white clay (kaolin), and observe the surface after drying. If cracks are present in the blade, the color of the solution will appear on the white clay, which can be easily identified with the naked eye. Blades with cracks should not be used and need to be re-welded.
I. Inspection of weld strength: Grind the back of the cutting tool with a green silicon carbide grinding wheel and observe the thickness of the solder layer, which should be controlled to within 0.15 mm. There should be no pores or insufficient solder on the supporting surface of the blade. The length of unfilled welds should not exceed 10% of the total weld length. If pores are present, the blade may detach during cutting.
II. Inspection of blade position in the tool holder: If the blade is misaligned or sagging beyond technical specifications, it needs to be re-welded.
III. Inspection of welding strength: Tap the blade with a wooden hammer or copper hammer with moderate force, or strike the tool shank forcefully with an iron hammer. The blade is considered acceptable if it does not detach from the tool holder. Welding strength can be inspected using a sampling method; individual inspection of each tool is not necessary.
IV. Inspection of blade flatness: If there are noticeable dents on the blade surface, it indicates that the blade has been overheated and deformed. The blade should be removed and a new blade re-welded.
V. Inspection for cracks: If cracks are present in the cleaned blade, kerosene will seep into the cracks, appearing as black lines, which can be observed with the naked eye or with the aid of a 10-40x magnifying glass.
In addition, a color penetrant inspection method can be used: Use a solution composed of 65% kerosene, 30% transformer oil, and 5% turpentine, with a small amount of Sudan red added. Immerse the cutting tool blade in this solution for 10-15 minutes, remove it, wash it with clean water, apply a layer of white clay (kaolin), and observe the surface after drying. If cracks are present in the blade, the color of the solution will appear on the white clay, which can be easily identified with the naked eye. Blades with cracks should not be used and need to be re-welded.
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