On 2018-08-08 14:48:54
Heat treatment of misunderstanding
The examples of "several heat treatment problems that seriously mislead people" that we are going to discuss here are all encountered in our practical work, not invented, and this phenomenon is very common, many people have this kind of understanding of heat treatment.
1. The heat treatment hardness HRC of my product can only be 60HRC. 59 or 61 HRC I can't accept?
It is often encountered that the hardness value of the entrusted heat treatment product can only be on a certain value, and there can be no deviation! For example, if the hardness of heat treatment is required to reach 60HRC, and you reach 59HRC after heat treatment, or 61hrc is regarded as unqualified product. However, the allowable deviation of Rockwell hardness machine is still 1hrc! When you explain heat treatment to him, he or she will put on a "God's face": do you want to make my heat treatment products? Market competition! Heat treatment manufacturers have to take it on their own. How can heat treatment manufacturers do it well? Colleagues can definitely guess out!
2. The quenched workpiece is not cooled to room temperature and cannot be tempered?
Some people think that after quenching, when it has not cooled to room temperature, it can not enter the tempering process. In fact, the end point of martensitic transformation of many kinds of steel, especially low and medium carbon steel, is higher than room temperature. When it is cold to room temperature, it is easy to crack. After quenching, it can be transferred to tempering process as soon as possible.
3. The quenched workpiece must be tempered with temperature?
This method is not desirable, according to the martensitic transformation point of steel to determine the temperature of the furnace before tempering after quenching! In order to prevent quenching and cracking, it is not allowed to speculate. Generally speaking, tempering with temperature is adopted!