During the heat treatment process, the screw of a high-precision thread grinder is easily affected by various factors and is prone to distortion defects. After analyzing the causes of defects, it was found that using a high-frequency induction annealing machine for heat treatment had good results.
The analysis found that reducing and eliminating the residual stress of forging and machining is one of the effective measures to reduce the heat treatment distortion of the screw of 9Mn2V steel high-precision thread grinder.
(1) The forging heating temperature of the 9Mn2V steel screw blank is 1150℃, the holding time is calculated as 0.8min/mm, and it is forged in two fires. The final forging temperature is 750-850℃, and the forging blank margin is 12mm. After forging, no There are folds and cracks.
(2) Spheroidizing annealing. Use a high-frequency annealing machine to heat to 760°C, and then cool to 450°C at an appropriate speed. After spheroidization annealing, the pearlite spheroidization level should be level 2-4, and the network carbide should be level 2-3.
(3) Cold press straightening. The bending distortion of the screw should be less than 2.5mm, and parts with larger distortion should be straightened by cold pressing.
(4) Rough turning the blank, leaving a margin of 4-5mm for finishing.
(5) Bending distortion inspection. The bending distortion of the screw should be less than 2mm. If there are out-of-tolerance parts, stress relief treatment must be performed after straightening until the requirements are met.
Many manufacturers use the above process for heat treatment, and the high-precision thread grinder screws they produce have no distortion defects and meet the work requirements. What's even better is that this process is suitable for large-scale production and can greatly improve workers' production efficiency.
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GS-ZP-1200
