How to check the quality of blade welding?

Release time：2020-06-01　　　　 Time to browse

　　In order to guarantee the welding quality, the welded blade should be carefully inspected to find out the reason for the defect and improve it. Before inspection, the blade should be sandblasted or lightly rubbed to remove solder and impurities adhering to the surface of the blade and cleaned with kerosene. The items and requirements for inspection are as follows:

　　1. Check the weld strength: grind the back of a blade with a green silicon carbide grinding wheel, and check the thickness of the solder layer. The thickness shall be less than 0.15 mm. There should be no holes and insufficient solder at the bottom of tip support. The unfilled weld should be no more than 10% of the total length of the weld. If there are holes, the blade will fall off when cutting.

　　2. Check the position of the blade in the groove: if the blade is misplaced and drooping beyond the technical conditions, rewelding shall be carried out.

　　3. Check the welding strength: hit the blade with a wooden hammer or a red copper hammer with medium force, or hit the blade with an i-hammer with strong force, and then the blade does not fall off from the body of the knife as qualified. Check the welding strength of the blade, not necessarily one by one, also use the method of spot check.

　　4. Check the flatness of the blade: if there are obvious pits on the blade, it means that the blade overheats and deforms, so the new blade should be burned and rewelded.

　　Five, check the cracks: after cleaning the blade by kerosene, if there are cracks in the blade kerosene will permeate into the cracks and appear black lines, with the naked eye can be observed. Also can use 10-40 times magnifying glass to observe.

　　Check blade crack, also can use color flaw detection method: use 65% kerosene, 30% transformer oil and 5% turpentine to adjust the solution, slightly add some Sudan red. Place the blade part of the lathe tool in the solution for 10-15 minutes, then wash it with clean water, apply a layer of clay (kaolin), and observe the surface after drying. If there are cracks in the blade, the color of the solution will be revealed on the clay and can be seen with the naked eye. The cracked blade cannot be used and needs to be welded again.

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