In order to save the cost and save the cost, many manufacturers are limited by the mechanical processing conditions and funds, and there is no way to make the spare parts of the equipment in a professional and standard heat treatment. It is often damaged, repaired, altered or scrapped. This paper introduces two ways of tempering heat treatment:

1, double liquid quenching: the key slot steps of the fine shaft are heated to the quenching temperature 820 C~840 C with the gas cutting torch, the oxygen acetylene flame, after quenching and tempering, and then for about 10 minutes, then the 10% salt water solution is then cooled for 7~8 seconds, and then cooling to the normal temperature in the air.

2. high temperature tempering: after double liquid quenching, the key step of the shaft cooling to the normal temperature is heated by oxygen acetylene flame to high temperature tempering temperature 500 C~540 C for 10 minutes, and then cooling to normal temperature in the air.