The screw is a key transmission part of the machine tool. It is a transmission and positioning functional component that converts rotational motion into linear motion or converts linear motion into rotational motion. It is widely used in the feed mechanism and adjustment movement structure of various machine tools. It can Ensure the accuracy and uniformity of linear motion. During the operation of the machine tool, the screw has to bear huge friction. Therefore, it is necessary to use medium frequency induction heating equipment to quench the screw. Today, we take the S7332 thread grinder precision trapezoidal screw as an example to briefly talk about its quenching process.
S7332 thread grinder precision trapezoidal screw, grade 5 accuracy, made of 9Mn2V steel. Heat treatment technical requirements: the depth of the hardened layer is 5-6mm, the hardness at φ30mm×75mm is ≥50HRC, the hardness of the remaining parts is 54-58HRC, the metallographic structure is fine needle-like martensite + uniformly distributed carbides, radial circular runout ≤ 0.7mm.
The process flow of the precision trapezoidal screw of the S7332 thread grinder is: blanking - quenching and tempering - rough turning of the outer circle - high temperature aging - fine turning of the outer circle - rough grinding of the outer circle - medium frequency induction quenching - hot straightening - cold treatment - tempering - Rough grinding of outer circle and thread - low temperature aging - fine grinding of outer circle and thread - low temperature aging.
According to the required hardened layer depth of the screw, medium frequency induction heating equipment is selected. The horizontal quenching machine tool has three quenching brackets, one at the rear and two in the middle.
The outer circumferential part of Tr60 is heated by medium frequency induction at 840-850°C and cooled by tap water for hardening; the outer circumferential part of φ74.5mm is tempered by medium frequency induction quenching by regular heating. After the temperature is raised to 880°C by heat conduction, compressed air is used for cooling.
Medium frequency induction quenching process: the output power is 80kW, the voltage is 342-430V, the current is 120A, the power factor is 0.95, the inner diameter of the inductor is φ80mm, the height is 20mm, it can pass φ74.5mm, and the cooling water sprayer size is φ80mm ( Inner diameter) × 40mm (height). The sensor moving speed is 100mm/min.
If the bending distortion is out of tolerance after medium frequency induction quenching, it should be straightened while it is hot. Use a press for straightening. Make the radial circle runout ≤0.5mm.
After the above processing, combined with the precision dimensional control of machining, it can meet the performance and accuracy requirements of high-precision (accuracy ≤ level 3) grinder screws.
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GS-ZP-1200
