Process analysis of heat treatment of block gauges using medium frequency induction heating power supply

Block gauge is a standard gauge block for measuring length and calibrating measuring tools in the machinery manufacturing industry. Its general shape is a cube or cuboid. It has high requirements for dimensional accuracy, dimensional stability and smoothness, so its performance is required to be as follows:

1. High dimensional accuracy

2. Dimensional stability should be maintained during long-term storage and use

3. The surface has high hardness and wear resistance

4. It has good grinding and processability after quenching

5. High corrosion resistance and surface finish

In order to meet the working requirements of the block gauge, many manufacturers use medium frequency induction heating power to heat treat it, and the effect is very good, meeting its performance requirements. Today, the technical staff of Zhengzhou Gou's will tell you about the medium frequency heat treatment process of block gauges.

1.Preparatory heat treatment

The blank is annealed using a medium frequency induction heating power supply. The process is (790-810)℃×(4-5)h-(690-710)℃×5h. The furnace is cooled to 500℃ and air-cooled out of the furnace. The purpose is to reduce the hardness (179 -207HB), which facilitates mechanical processing, reduces internal stress, stabilizes the structure and size, and obtains spherical pearlite, which prepares the structure for the final heat treatment.

In order to eliminate the processing stress after machining, a medium frequency induction heating power supply should be used for stress relief annealing, that is, heating at 600 to 650°C, and after 120 minutes of heat preservation, the power is turned off and cooled to about 300°C for cooling.

In order to obtain high and uniform hardness, eliminate the stress caused by processing, and reduce quenching deformation, normalizing or quenching and tempering treatment can also be used (the process specification is heating at 870-880°C and tempering at 650-720°C).

2. Final heat treatment

In order to improve the dimensional stability of the block gauge, it is recommended to adopt the following process specifications: preheating 650-700℃-heating (860℃×15min)-quenching oil cooling-cold treatment (-75℃×60min)-tempering (three times low temperature tempering 150℃×70min)-aging 120℃×48h-fine grinding-aging 120℃×10h.

This article briefly introduces the medium-frequency heat treatment process of block gauges, and hopes that everyone can apply it to work. Here, I would also like to remind everyone that when performing quenching heat treatment on the workpiece, we should be very serious and careful to avoid unnecessary defects in the workpiece and affect its quality.