How to Check the Quality of Blade Welding

In order to ensure the welding quality, the turning tool after welding should be carefully inspected to find out the cause of the defect and improve it. Before inspection, the turning tool should be sandblasted or lightly ground to remove solder and impurities adhering to the surface of the blade, and cleaned with kerosene. The items and requirements to be checked are as follows:

1. Check the weld strength: Grind the back of a turning tool with a green silicon carbide grinding wheel, check the thickness of the solder layer, and the thickness is required to be below 0.15 mm. There should be no air holes and insufficient solder on the bottom surface of the tool tip support, and the weld that is not filled with solder should not be greater than 10% of the total length of the weld. If there are air holes, the blade will fall off when cutting.

2. Check the position of the blade in the groove: If the blade is dislocated and sagging exceeds the technical requirements, it should be re-welded.

3. Check the welding strength: Use a wooden hammer or a red copper hammer to strike the blade with medium force, or strike the blade with a strong I hammer. At this time, the blade does not fall off from the groove, which is qualified. To check the welding strength of the blades, it is not necessary to check them one by one, and a random inspection method is also used.

Fourth, check the flatness of the blade: if there are obvious pits on the blade, it means that the blade is overheated and deformed, and a new blade should be burned and re-welded.

5. Check for cracks: After the blade is cleaned with kerosene, if the blade has cracks, the kerosene will penetrate into the cracks and black lines will appear, which can be observed with the naked eye. It can also be observed with a magnifying glass of 10-40 times.

Check the blade for cracks, and color flaw detection can also be used: a solution of 65% kerosene, 30% transformer oil and 5% turpentine is used, and a little Sudan red is added. Put the blade part of the turning tool in the solution for 10-15 minutes, then wash it with water, apply a layer of white clay (kaolin), and observe the surface after drying. If there are cracks on the blade, the color of the solution will be in the white clay. It can be seen with the naked eye. Cracked blades cannot be used and need to be re-welded.

In addition to the several commonly used 7J welding methods described above, there are also methods such as oil protection, electric furnace, forge furnace and furnace brazing with reducing gas, which will not be introduced in detail here.