Bright annealing heat treatment process and equipment for electric shaver cover

Bright annealing heat treatment process and equipment for electric shaver cover

The electric shaver cover is an important part of the electric shaver. During operation, the blade and the cover slide relative to each other, and its function is equivalent to sharpening the edge. The hardness of the cover is required to be (47+2) HRC. Since the cover is in contact with the skin, the surface requires gloss and good corrosion resistance. At the same time, due to the complex shape of the cover, the workpiece material should have good stamping properties. In addition, the cover material should have the characteristics of low heat treatment strengthening temperature, minimal deformation, and easy bright heat treatment. According to the above requirements, the cover is made of OCr15Ni7M02AI semi-austenitic precipitation hardened stainless steel, and its grain size is ASTM standard grade 10-14. . During production, it was found that it is easier to achieve the mechanical performance indicators of the cover that meet the technical requirements. However, defective products, reworked products, and even product scrapping often occur because the brightness, corrosion resistance, and micro-deformation requirements of the workpiece are not up to standard. Therefore, the main purpose of improving the process is to achieve bright annealing heat treatment and micro-deformation treatment.

The electric shaver cover is an important part of the electric shaver. During operation, the blade and the cover slide relative to each other, and its function is equivalent to sharpening the edge. The hardness of the cover is required to be (47+2) HRC. Since the cover is in contact with the skin, the surface requires gloss and good corrosion resistance. At the same time, due to the complex shape of the cover, the workpiece material should have good stamping properties. In addition, the cover material should have the characteristics of low heat treatment strengthening temperature, minimal deformation, and easy bright heat treatment. According to the above requirements, the cover is made of OCr15Ni7M02AI semi-austenitic precipitation hardened stainless steel, and its grain size is ASTM standard grade 10-14. . During production, it was found that it is easier to achieve the mechanical performance indicators of the cover that meet the technical requirements. However, defective products, reworked products, and even product scrapping often occur because the brightness, corrosion resistance, and micro-deformation requirements of the workpiece are not up to standard. Therefore, the main purpose of improving the process is to achieve bright annealing heat treatment and micro-deformation treatment.

In order to obtain a heat treatment effect of bright luster, no erosion and micro-deformation for the OCr15Ni7M02Al stainless steel cover, a fully sealed bright quenching furnace for the cover was developed experimentally. The shell bright quenching furnace consists of four parts: the furnace body, the inlet and outlet basket device, the muffle tank device and the gas supply system. The equipment power is 4kW and the maximum operating temperature is 950℃.

In heat treatment production, the key points of process operations are as follows:

(1) To remove oil and dirt on the surface of the workpiece, use gasoline to clean it and blow it twice, then shake it in acetone to clean it. Do not touch it with your hands.

(2) Before starting, cool it with water. When the temperature reaches 600°C, fill it with nitrogen to clean the muffle tank. Fill it with 5 times the volume of gas and control the flow rate at about 50L/h.

(3) The high temperature solution treatment temperature is 925°C. When it reaches temperature, pull out the pull rod and rotate the butterfly valve 90 degrees. , causing the workpiece to fall into the basket. 15 minutes after the workpiece enters the heating zone, the material basket is pulled back to the charging position, and the handle 1800 is turned to make the workpiece fall into the cooling water jacket for air cooling.

(4) Cold treatment. The workpiece after high temperature treatment is placed in an ice bath for cooling, the temperature is -700C ± 5RC, and the holding time is 8 hours.

In production, after the OCr15Ni7M02Al stainless steel cover has been treated with improved technology and self-made fully sealed bright quenching furnace equipment, the hardness has reached 474-435HV, the stamping yield is high, the surface of the workpiece is bright and clean, the deformation is small, the product quality is stable, and it meets the needs of electric shaving. Knife technical requirements. This self-made equipment can produce continuously and can produce 4,000 covers per shift, with obvious technical and economic benefits.