How to check the quality of blade welding?

Release time：2020-02-27　　　　 Time to browse

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

　　1. Check weld strength: grind the back of a lathe knife with a green silicon carbide grinding wheel, and check the thickness of the solder layer, which shall be less than 0.15mm. There should be no porosity and insufficient solder at the bottom of the tool tip support, and the welding seam with unfilled solder should not be more than 10% of the total length of the welding seam. If there are holes, the blade will fall off during cutting.

　　2. Check the position of the blade in the groove: rewelding shall be carried out if the blade is out of position and droop exceeds the technical requirements.

　　3. Check the welding strength: use wood hammer or copper hammer to hit the blade with medium force, or use I hammer to hit the blade with strong force. If the blade does not fall from the groove, it is qualified. Check the welding strength of the blade, not necessarily one by one check, also use spot check method.

　　4. Check the flatness of the blade: if there are obvious pits on the blade, it indicates that the blade is overheated and deforms, and the new blade should be burned down and re-welded.

　　5. Check for cracks: if there are cracks in the blade after cleaning with kerosene, kerosene will penetrate into the cracks and black lines will appear, which can be observed with the naked eye. It can also be viewed with a magnifying glass of 10-40 times.

　　To check for cracks in blades, color inspection is also available: a solution of 65% kerosene, 30% transformer oil and 5% turpentine, with some Sudan red. Place the turning knife blade part in the solution for 10-15 minutes, then wash it with clean water, apply a layer of white soil (kaolin), and observe the surface after drying for a thousand years. If there are cracks on the blade, the color of the solution will appear on the white soil, which can be seen with the naked eye. The cracked blade cannot be used and needs to be re-welded.

　　In addition to the above several commonly used car 7J welding methods, there are oil protection, electric furnace, forge furnace and reducing gas brazing furnace and other methods, here is not detailed.