Quenching agents commonly used when workpieces are quenched using medium frequency induction heating equipment

As we all know, the so-called quenching is a metal heat treatment process in which the metal workpiece is heated to a certain appropriate temperature and maintained for a period of time, and then immersed in a quenching medium for rapid cooling. Therefore, when the workpiece is quenched and heat treated using medium frequency induction heating equipment, it is not only the factors of the equipment itself that affect the quenching quality of the workpiece, but its cooling factors also have a great impact. Today, let’s take a look at the quenching agents commonly used when workpieces are quenched using medium frequency induction heating equipment.

The workpiece is quenched and heat treated with medium frequency induction heating equipment. The most commonly used quenching agent is water. It is generally suitable for carbon steel with a carbon mass fraction of less than 0.47%, as well as high carbon content, but low Mn, low alloy elements Cr, Low hardenability steel of Cu and Ni.

For low alloy steel containing a certain amount of Cr, Ni, Mn and other elements, since these steels require a low critical cooling rate for quenching, a quenching liquid with a lower cooling rate can be used, such as oil or a quenching liquid with polymers as additives. . Today, we will focus on polymer quenching fluid.

In recent years, quenching fluids with polymers as additives have been widely used in the induction quenching process. Its main function is to reduce quenching stress and prevent quenching cracks and deformation. The emulsion quenching agents widely used in the 1950s have been eliminated, and new polymer quenching agents can replace a wide range of quenching fluids from oil to brine. Since the quenching fluid contains anti-rust agents, it not only has the advantage of fire prevention, but also can prevent rust; however, polymer quenching fluid is more expensive and has stricter requirements for use and management.

Polymer quenching liquids with different contents have different cooling rates in the 300°C temperature range. The cooling rate in the 300°C temperature section has the greatest relationship with quenching stress. An excellent quenching fluid is preferably one that cools quickly at 600°C but cools slowly at 300°C. For medium carbon steel commonly used for induction hardening, a mass fraction of 5% is generally sufficient; for workpieces with complex shapes that require small quenching deformation and small wall thickness, a higher content should be used.

We have found through many tests that when the mass fraction of the polymer quenching liquid reaches 12%-15%, its cooling rate at 300°C is 30-20cC/s, which is equivalent to super-speed quenching oil; while the 300°C cooling rate of general quenching oil It is l0 degrees Celsius/s, which is lower than the content of polymer quenching liquid. Since oil quenching workpieces not only produce oil smoke and fire prevention problems, they also require cleaning procedures. Therefore, in recent years, the field of induction quenching has shown a trend of elimination.

Polymer quenching fluid has become a widely used quenching agent. When the workpiece is quenched and heat treated with medium frequency induction heating equipment, its materials are different and the quenching agent applied is also different. As a professional manufacturer of induction heating equipment, Zhengzhou Gou's has a good understanding of the heat treatment of various workpieces. If you want to know more about workpiece heat treatment, please feel free to leave us a message.