What are the main common methods for removing internal stress in cemented carbide

Heat treatment method

• Generally, cemented carbide is placed in a protective atmosphere furnace such as a vacuum furnace or a hydrogen furnace. Through low-temperature tempering treatment, the temperature is usually around 200-300 degrees Celsius, which can effectively reduce the residual stress inside the alloy caused by processing, etc., and will not affect the main properties of cemented carbide such as hardness.

Natural aging

• It is to place the cemented carbide workpiece in an indoor environment for a long time, generally several months, to allow the stress inside the alloy to be naturally released. However, this method is time-consuming and relatively inefficient.

In addition to low-temperature tempering, the following methods can also be used to remove internal stress in cemented carbide:

Vibration aging

• Support the cemented carbide workpiece with an elastic device and tungsten carbide cold headin die vibrate the workpiece through a vibration device. During the vibration process, the crystal structure inside the workpiece will undergo microscopic changes, and the stress will be redistributed and released. Generally, vibration for a few hours can have a certain stress relief effect. This method is short in time, highly efficient, and relatively simple to operate.

Cryogenic treatment

• Place the cemented carbide in a low-temperature environment (such as liquid nitrogen, the temperature can be as low as -196℃), keep it for a period of time and then take it out. During the rapid temperature change, the internal structure of the alloy changes, so that the residual stress is released. The treatment time may vary from several hours to dozens of hours, depending on the size of the workpiece and other conditions.