High-frequency induction heating equipment manufacturer shares tobacco leaf shredder blade heat treatment process

The blade of the tobacco leaf shredder is under complex stress conditions when working, so the overall shape of the blade is required, the cutting edge requires high hardness and wear resistance, and the central part has good elasticity.

During the trial production of the blade, process tests such as stamping forming, arc molding, arc molding, alkali bath graded quenching, high-frequency induction quenching, and nitriding were carried out to target the R530mm dish-shaped curvature of the blade and the high hardness of the cutting edge. . Due to poor arc forming and edge warping deformation, the pass rate is only about 30%.

The forming quality of the butterfly arc of the blade depends on the plasticity of the blade forming process, while the hardness of the cutting edge depends on the effect of quenching strengthening. It is difficult to achieve a good combination of plasticity, elasticity and high hardness using general processing methods. The new process of "forming + quenching composite treatment" solves this problem well.

1) Blade blank, technical requirements and process flow. The raw material of the blade is 1.5mm thick 65Mn cold-rolled steel strip, the metallographic structure is sorbite, and the hardness is >300HBW.

The technical requirements of the blade: the disc arc radius is R500-R560mm; the edge flatness is ≤0.20mm, and the hardness within the edge width of 8mm is 48-53HRC. The production process of the blade: punching blank, turning the cutting edge, heat treatment, galvanizing the surface, and grinding the cutting edge.

2) Blade forming and heat treatment. According to the radian requirements of the blade, a special quenching fixture is designed, and all the blades that require high arsenic eagle are exposed outside the fixture, and the inside is fastened with a template, and two pieces are clamped on each hanging fixture. The heat treatment process is shown in n circle 2-69. After quenching in salt bath and oil for 3 minutes, take out the demoulding, remove the residual salt on the blade surface, and adopt the tempering and straightening method. The tempering fixture is also designed according to the radian of the blade. There are 100 pieces in one hanging clamp, which can be tempered in time, tempering 3 times, 1 hour each time. After the first two temperings, tighten the nuts of the fixture while it is still hot, and then put it in the furnace to continue to keep warm. After the third tempering, come out of the furnace and air-cool to room temperature before demoulding, and clean it with hot water.

The surface of those who pass the inspection shall be galvanized.

3) Quality inspection. Use the R530 arc template to check the entire disc arc radius, and the pass rate is 96%; place the blade on the flat plate and check the edge flatness, the pass rate is 94%, and the edge hardness pass rate is 98%.