Understanding the Difference between Stress Relieving and Heat Treating in Manufacturing Custom Coil Springs

Custom coil springs play a vital role in various industries, and it is essential to understand the different processes involved in manufacturing them. Stress relieving and heat treating are two crucial processes that contribute to the quality and performance of coil springs. In this article, we will explore the differences between stress relieving and heat treating, as well as the benefits of each process. Additionally, we will discuss the problems that can arise if coil springs are not properly heat treated and stress relieved.

Stress relieving is a process that involves heating coil springs made from pre-tempered spring steel to a specific temperature and holding them at that temperature for a certain period. This process aims to reduce internal stresses caused by the manufacturing process. On the other hand, heat treating involves subjecting the coil springs to specific temperature ranges to achieve desired hardness and strength. Heat treating typically involves heating the springs to a high temperature, followed by quenching and tempering stages.

Pre-tempered spring wire being formed into a custom compression spring at OmniCoil Spring Works.

Benefits of Stress Relieving Coil Springs:

1. Reduced Internal Stresses: Stress relieving eliminates residual stresses, preventing potential failures or deformations in the coil springs during service.

2. Increased Durability: By minimizing inherent stresses, stress relieving improves the fatigue life of the coil springs, ensuring their long-term reliability.

3. Improved Formability: Stress relieving enhances the coil springs' formability, allowing for better shape retention and reducing the risk of unwanted distortion.

4. Enhanced Machinability: The stress relieving process makes the coil springs easier to machine, reducing manufacturing difficulties and costs.

5. Consistent Performance: Proper stress relieving ensures consistent mechanical properties throughout the coil springs, resulting in predictable and reliable performance.

Springs being stress relieved after coiling.

Benefits of Heat Treating Coil Springs:

1. Controlled Hardness: Heat treating allows manufacturers to achieve specific hardness levels in the coil springs, providing the desired strength and resilience for different applications.

2. Increased Strength: Through heat treating, coil springs can attain higher tensile strength, enabling them to withstand heavy loads and harsh operating conditions.

3. Improved Elasticity: Heat-treated coil springs exhibit excellent elastic properties, allowing them to efficiently absorb and release energy, resulting in enhanced performance.

4. Dimensional Stability: Heat treating helps maintain the dimensional stability of coil springs, preventing excessive deformation or changes in shape during service.

5. Tailored Material Properties: Heat treating offers the flexibility to modify the properties of the coil springs based on the application requirements, such as corrosion resistance or magnetic properties.

   
   

If coil springs are not properly heat treated, several problems can arise. They may not achieve the desired hardness, leading to insufficient strength and premature failure. Conversely, if the springs are excessively heat treated, they may become brittle and prone to fracture. Improper heat treatment can also result in dimensional inconsistencies, adversely affecting the performance and fit of the coil springs.

Similarly, inadequate stress relieving can cause residual stresses to remain within the coil springs. These residual stresses can lead to stress corrosion cracking, reduced fatigue life, and distorted or misshapen springs. Without proper stress relieving, the coil springs may also experience relaxation over time, causing a loss of initial tension and compromised performance.

Stress relieving and heat treating are critical processes in manufacturing custom coil springs. While stress relieving reduces internal stresses and improves formability, heat treating enhances strength and control over material properties. Neglecting proper heat treatment and stress relieving can result in coil springs that fail to meet performance expectations, suffer from premature failure, or exhibit dimensional inconsistencies. Manufacturers must prioritize these processes to ensure the longevity, reliability, and optimal performance of coil springs in a wide range of applications.

For more information about which one of these processes is right for your spring application, contact one of the skilled staff members at OmniCoil Spring Works Inc.