Methods for preventing and controlling heat treatment deformation

Heat treatment deformation is a common challenge in manufacturing, and several techniques can be applied to minimize and control it effectively. Below are methods that help in reducing deformation during heat treatment:

1.Reverse Bending Method

For shaft components that are prone to deformation, a pre-applied stress can be introduced before quenching. This involves bending the part in the opposite direction of its expected deformation. By compensating for the bending deformation anticipated after quenching, this method reduces the need for straightening work. It is especially effective for parts with significantly uneven cross-sections.

Heat treatment

2.Static Quenching Method

This method requires the quenching liquid to be uniform in temperature and in a static state, just after being stirred. The part is held with tongs and submerged into the quenching liquid. Compared to suspending the part with wire, this approach significantly reduces deformation.

3.Designing Uniform and Symmetrical Parts

Designing the cross-section of components to be as uniform and symmetrical as possible can help reduce deformation. When necessary, slots can be added for process purposes. For example, a boring rod may have two symmetrical slots, with only one being functional, while the other is designed to minimize heat treatment deformation.

4.Using Specialized Quenching Fixtures

For parts with symmetrical cross-sections, specialized fixtures can be used during quenching. After removing the part from the furnace, it is placed in a dedicated fixture and then submerged vertically into the quenching liquid. The fixture restricts the deformation, keeping it within the allowable tolerance.

5.Embedded Salt Bath Heating

While insertion-type salt baths can cause uneven heating and bending, embedded salt bath furnaces provide uniform heating and are more energy-efficient. Fluidized bed furnaces can also be used for even heating.

6.Vertical Suspension for Long Parts

Long parts should be stored in a manner that prevents bending due to their weight. It is best to hang them vertically on racks. During long-distance transportation, multiple inflatable air cushions can be used to balance the parts and provide shock absorption.

7.Stress Relief Before Quenching

For critical parts prone to deformation, such as precision rods, stress-relief processes like annealing or normalizing should be performed before quenching. These processes refine the grain structure and reduce internal stress. During quenching, strict control over the heating temperature is essential.

By following these methods, manufacturers can significantly minimize heat treatment deformation, ensuring the quality and precision of their components.