Heat treatment quality inspection
Quality inspection is a very important link in the production and manufacturing process of mechanical blades. It must be strictly controlled and carefully checked.
(1)Inspection of raw material steel plates before entering the factory. Raw materials must be inspected and qualified before they can be put into storage. Inspection items include chemical composition, decarburization layer depth, carbide uniformity, carbide particle size, test quenching hardness, surface quality, etc.
(2)Quenching austenite grain size When I visited the Japanese blade production site, I found that this item was not checked before the furnace, and some European and American countries did not inspect it either. But it does not work in my country. If a tool factory does not conduct metallographic inspection before the furnace, there will definitely be quality problems. Because our management lacks scientificity, there is no quenching by furnace number, let alone signing a contract with the steel mill according to the use of the blade, so the quenching before the furnace is very blind. We must control the grain size within the ideal range according to the specific product.
(3)Carbide Carbide is a double-edged arrow for the tool industry. On the one hand, it is the basis of high hardness, high wear resistance and high red hardness. On the other hand, it is easy to cause heat treatment quality accidents. Heat treatment is nothing more than the transformation or conversion of carbides. The pre-quenching inspection of high-speed steel must focus on the dissolution of carbides. The grain size can only reflect the heating temperature, and the degree of carbide dissolution is of essential significance.
(4)Hardness The hardness must be tested after quenching and tempering. The hardness of high-speed steel blades after quenching must be within an appropriate range. According to the author's experience, high hardness indicates low quenching temperature, and low hardness indicates high quenching temperature. In many papers, the author repeatedly emphasized the basic principle that "hardness is a surface phenomenon, and microstructure is the essence". It is easy to achieve the hardness required by the process, but it is not easy to achieve the ideal microstructure. The gap between my country and foreign blades is not hardness but microstructure.
For mechanical blade hardness testing, my country uses Rockwell hardness, Japan uses Shore hardness, and Europe and the United States generally use Vickers hardness.
With the technological progress of industries such as wood and printing, higher requirements will be placed on the performance of blades. The development of science and technology is endless, and the materials and heat treatment processes of mechanical blades will continue to be updated. At present, my country's nitriding ion plating composite coating technology has been successfully applied to 65Mn steel paper cutting blades, and new heat treatment technologies such as laser quenching and vapor deposition are under development. What is core competitiveness? Heat treatment technology is the core competitiveness of mechanical products. If you do a good job in heat treatment, you can beat several.
