Control of heat treatment normalizing, quenching, tempering, annealing temperature and holding time
Jan. 21, 2022
Control of heat treatment normalizing, quenching, tempering, annealing temperature and holding time
1) The temperature rise and insulation of heat treatment are based on the instrument temperature. During the whole heat treatment process, it is necessary to often check whether the temperature of furnace and workpiece is consistent with the temperature displayed by the instrument. If there is any problem, inform the electrician to check and repair the instrument in time.
2) The heat treatment worker shall be diligent in three aspects: frequently watching the furnace temperature, frequently watching the material temperature and frequently adjusting and controlling, so as to ensure that the temperature of all parts in the furnace is uniform and the positive pressure is maintained in the furnace.
3) Comprehensive selection of normalizing, quenching, tempering and annealing temperatures and control in strict accordance with the requirements of the instruction are the primary conditions to ensure the quality of heat treatment. Because the heating temperature is low, the phase structure transformation will not occur; If the heating temperature is too high, the austenite grain will grow too large, resulting in the difficulty of phase structure transformation during cooling. Therefore, we must strictly follow the requirements of the operation instructions, and do not set the high and low at will.
4) The holding time of normalizing, quenching, tempering and annealing shall also be strictly controlled. Because insufficient time will make the transformation of phase structure incomplete, and excessive extension of time will make the phase structure grow up and the performance deteriorate.
5) Generally, there should be a uniform temperature stage before the insulation stage of heat treatment. The average temperature is calculated when the instrument temperature reaches the insulation temperature; When the surface temperature of all workpieces in the furnace reaches the insulation temperature, the homogenization ends and the insulation begins.
