Woodworking tool wear resistance
According to the woodworking tool wear theory, to improve the wear resistance of the tool, the main ways are: improve the ability of the tool to resist mechanical abrasion and corrosion wear.
1. Surface heat treatment
Through the appropriate surface heat treatment method, the structure of the metal can be changed to improve the surface hardness of the tool and increase its wear resistance. Generally speaking, the wear resistance of ferritic steel is the worst, the wear resistance of martensitic steel is better, and the wear resistance of bainitic steel is the best. Tempered martensitic steel obtained after quenching and tempering has significantly higher wear resistance than pearlite + ferritic steel obtained after normalizing. The bainite structure can be obtained by isothermal quenching, and under the same hardness, higher wear resistance can be obtained than ordinary quenching and tempering. The wear resistance of the pearlitic lamellar structure and the spheroidized structure is better than that of the spheroidized structure when the carbon content of the steel is the same. Before the carbon content of the pearlitic lamellar steel increases to close to the eutectoid composition, the wear resistance increases significantly with the increase of carbon content. When the eutectoid composition is exceeded, the wear resistance tends to decrease due to the presence of network carbide.
It can be seen that different metallographic structures have different wear resistance, and through the appropriate surface heat treatment method, the metal structure can be transformed, the surface hardness of the tool is increased, and the wear resistance is increased. Commonly used surface heat treatment methods are: laser quenching, high-frequency quenching, electric contact quenching. After the tool surface is heat treated by the above method, the hardness of the quenching layer can increase HRC 2-4, and the durability can be mentioned about 1.
2. Layer infiltration technology
Infiltration layer technology is a chemical heat treatment method by changing the chemical composition of the tool surface to improve the wear resistance and corrosion resistance of the tool, metal infiltration layer technology has a solid method, liquid method and gas method, each method has many different heat treatment processes. There are mainly carburizing, nitriding, carbonitriding, sulfurizing, sulfuritriding, boriding and carbonitriding. Because the woodworking knife is made of high-quality high-carbon steel (carbon tool steel), alloy tool steel and high-speed steel, it is often infiltrated into the tool surface of boron, vanadium and other elements.
Boronizing is the infiltration of boron into the surface of the tool to form a protective layer with high hardness and good chemical stability. The hardness of the boronizing layer is HV1 200-1800, the depth of boronizing is 0.1-0.3mm, and the single-phase Fe2B boronizing layer with small brittleness can be obtained by common solid boronizing method.
In the molten borax bath, adding vanadium powder or vanadium oxide and reducing agent, the tool is heated to 850-1000℃, and the heat preservation is 3-5h, which can obtain a thickness of 12-14 μm, and the hardness of HV1 560-3380 extremely hard vanadium carbide layer.
3. Coating technology
The adaptability of electroplating is very strong, and it is not limited by the size and batch of the workpiece, and can be electroplated on the matrix of iron base, non-iron base, powder metallurgy parts, plastics and graphite
4. Thermal spraying technology
Using gas, liquid fuel or arc, plasma arc as a heat source, the metal, alloy, cermet, oxide, carbide and other spray materials are heated to a molten or semi-molten state. A method of atomizing, spraying, and depositating it on the surface of the pretreated workpiece by high-speed airflow to form a firmly attached surface layer
5. Coating technology
The tool base is coated with a thin layer (5-12μm) of refractory metal (or non-metallic) compounds with high wear resistance to improve tool durability, corrosion resistance and high temperature oxidation resistance
If want to discuss more, please contact SHJ.
