How to check the quality of blade welding?

In order to ensure welding quality, the welded blades should be carefully inspected to identify the cause of defects and make improvements. Before inspection, the blade should be sandblasted or lightly ground to remove solder and impurities adhering to the surface of the blade, and cleaned with kerosene. The inspection items and requirements are as follows:

1、 Check the strength of the weld seam: Grind the back of a blade with a green silicon carbide grinding wheel, and check the thickness of the solder layer. The thickness is required to be below 0.15 millimeters. There should be no air holes or insufficient solder at the bottom surface of the tool tip support, and the weld seam that is not filled with solder should not exceed one tenth of the total length of the weld seam. If there are pores, it will cause the blade to fall off during cutting.

2、 Check the position of the blade in the slot: if the blade is misaligned or sagging exceeds the technical requirements, it should be re welded.

3、 Check welding strength: Use a wooden or copper hammer to strike the blade with moderate force, or use an I-hammer to strike the blade with strong force. If the blade does not detach from the blade body, it is considered qualified. Check the welding strength of the blades, not necessarily one by one, but also through spot checks.

4、 Check the flatness of the blade: If there are obvious pits on the blade, it indicates that the blade is overheated and deformed. It should be burned down and re welded with a new blade.

5、 Check for cracks: After cleaning the blade with kerosene, if the blade has cracks, 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 10 to 40x magnifying glass.

To check for blade cracks, color inspection method can also be used: a solution composed of 65% kerosene, 30% transformer oil, and 5% turpentine, with a slight addition of Sudan red. Place the blade of the turning tool in this solution for 10-15 minutes, rinse with clean water, apply a layer of white clay (kaolin), and observe its surface after baking. If there are cracks on the blade, the color of the solution will be exposed on the white clay, which can be seen with the naked eye. Cracked blades cannot be used and need to be re welded.

In addition to the commonly used welding methods for car 7J mentioned above, there are also methods such as oil protection, electric furnace, forging furnace, and furnace brazing with reducing gas, which will not be detailed here.