Metal stamped parts need to be durable and highly functional and one method of improving the longevity of these parts is heat treatment. In fact, this technique of applying controlled heating and cooling also enhances a part’s strength and performance.   

Heat treatment after sheet metal stamping improves a part’s lifespan by altering its microstructure. This process enhances qualities like hardness, strength, flexibility, etc., making the parts more durable and resistant to wear and tear. It makes sure that the products are ready for enduring demanding environments. 

Curious about how this process works and what benefits it brings? In this guide, we’ll focus on the benefits of improving part longevity with heat treatment, different types of this method, and its applications. 

Improving Part Longevity with Heat Treatment 

Metal stamped parts are tough, but sometimes they need an extra boost in strength for certain applications. And heat treatment is the right choice for that purpose. It’s often necessary to meet an OEM’s specific requirements for things like hardness, corrosion resistance, or wear life after stamping. 

What Is Heat Treatment and How Does It Work? 

Heat treatment is a process where a metal is heated to a certain temperature and then cooled in a controlled way to change its properties. The purpose? To make it stronger, harder, more wear resistant, or even more flexible, whatever is the requirement. 

This process works by changing a material’s microstructure, which means tweaking the way its molecules are arranged. By adjusting the heat and cooling rates, manufacturers can fine-tune the metal part’s various properties. 

For stamped parts, heat treatment can be an important step to meet specific requirements. The variables of the process, such as temperatures, cooling rates, and times, will be different based on factors like the part’s material, design, and purpose.

Benefits of Heat Treatment for Stamped Parts 

Improving part longevity with heat treatment is only one benefit of this process. A precision sheet metal fabricator​ can use this technique to suit a wide range of needs. Let’s break down its major advantages:  

a. Improving Workability

Metals that are too tough to machine or bend can be made more manageable through processes like annealing. This is particularly helpful if the part needs further machining, as it reduces internal stresses and prevents deformation. For example, you can soften just one area of a part to make it easier to work with, without affecting the rest of the piece. 

b. Better Wear Resistance and Durability

Heat treatment can harden metals, which increases their ability to resist wear. This is perfect for parts exposed to harsh conditions, as it helps them last longer. By using surface hardening (case hardening), you can make even cheaper metals like steel tougher and more durable. 

And for parts that only need a specific area hardened? Heat treatment can focus on those spots without impacting the whole part, thanks to techniques like induction hardening. 

c. Increasing Strength and Toughness

Enhancing both strength and toughness of a metal part is a bit of a balancing act. Increasing strength might make a material more brittle, but heat treatment allows you to control this trade-off. By tempering the part after hardening, you can reduce brittleness without compromising the toughness. 

d. Tweaking Magnetic Properties

If your part needs to have specific magnetic properties, heat treatment can help there too. Some metals become magnetized after certain processes like stamping or bending. A targeted annealing process can reduce the magnetic permeability, which is crucial if that part will be used in an electronic or magnetic-sensitive environment. 

e. Reducing Internal Stress

The stamping process can introduce internal stresses to metal parts, which might lead to distortion or early failure. Heat treatment can relieve these stresses, resulting in a part that’s more stable and has a longer lifespan. 

Types of Heat Treatments Commonly Used After Stamping 

There are different types of heat treatment techniques, and each enhances different properties of a metal part. Here we’ve discussed the most common types: 

1. Annealing

After the stamping process, metals can be hard and brittle, which isn’t ideal for many applications. Annealing softens the metal by heating it to a specific temperature and then slowly cooling it. This reduces internal stresses, making the material more ductile and easier to work with. It’s especially useful when preparing a part for machining or additional forming processes.

2. Quenching

Quenching is all about rapid cooling. Once the stamped part is heated to a high temperature (often in a furnace), it’s suddenly cooled by immersion in a quenching medium like water, oil, or air. This fast-cooling process transforms the metal’s structure, making it much harder and more wear-resistant.

However, this process can make the material brittle. For this reason, it’s usually followed by tempering. This combination gives you a nice balance of hardness and toughness.

3. Tempering

During tempering, the metal is reheated to a lower temperature, which reduces brittleness and makes it tougher, without losing its hardness. It’s a bit of a balancing act; hardness for strength, and toughness for durability. Depending on the tempering temperature, you can control how soft the metal will be. 

4. Normalizing

If the stamping process has left your metal parts with internal stresses, normalizing can help. In this treatment, the material is heated above its critical temperature and then air-cooled. 

Normalizing helps to refine a material’s grain structure and remove internal stresses that might have built up during cold working. It strikes a nice balance between improving strength and maintaining a good level of flexibility. 

5. Case Hardening

Case hardening is a clever technique when you want to have a part with a tough exterior and a softer interior. This process is often used for low-carbon steels. It involves adding extra carbon to the surface of the metal, creating a hard, wear-resistant outer layer. This is perfect for parts that will face heavy wear, like gears or tool components, but need to remain somewhat flexible on the inside. 

6. Induction Hardening

Induction hardening is a high-tech option that uses electromagnetic induction to heat specific parts of the metal. It’s super precise, so you can harden specific areas, such as the surface of a shaft or a bearing journal, without affecting the entire part. This targeted hardening process is often followed by quenching to lock in the toughness. 

7. Precipitation Hardening (Aging)

The method is applicable to only certain alloys for increasing their strength. It’s a bit of a slow process, where you heat the metal to a specific temperature and then cool it under controlled conditions. Over time, this allows the formation of tiny particles within the metal’s structure, improving its strength and hardness.  

Applications Requiring Heat-Treated Stamped Components 

Improving part longevity with heat treatment is a popular technique for metal stamped parts. These parts are used in various industries, including: 

i. Automotive Industry

The automotive industry is one of the biggest consumers of heat-treated stamped components. Many car parts need to withstand high temperatures, pressure, and constant wear. Heat treatment gives these parts the durability they need.

Take gears and transmission parts, for example. They need to stay strong while dealing with a lot of movement and friction. Treating them with heat enhances their strength and wear resistance, making sure they keep working smoothly for years.

Then there are engine components like valves, camshafts, and connecting rods. These parts are exposed to extreme temperatures and mechanical stress, and heat treatment helps them handle all that pressure without cracking or wearing down. 

The same goes for chassis and suspension parts. Components like springs and control arms benefit from heat treatment, allowing them to resist fatigue and handle heavy loads.

ii. Aerospace Industry

For structural components, like the frame of an aircraft or its landing gear, heat-treated stamped materials offer the right balance of strength and lightness. 

Engine parts in jet engines, for example, face not only high temperatures but also intense mechanical stress. Heat treatment ensures these parts can keep up, performing under pressure and heat without giving in.

iii. Construction and Mining

In the construction and mining industries, machinery components are constantly exposed to heavy impacts and intense workloads. There are components like gears, shafts, and housings, which are typically made of iron castings. They need to be heat treated to improve their toughness and wear resistance.

With impact resistance being so critical in these industries, heat treatment ensures that these parts can handle shock loads without breaking down. 

iv. Tools and Dies

The tools and dies used in manufacturing also rely on heat-treated components. Cutting tools need to stay sharp while enduring a lot of wear and tear. Heat treatment enhances their hardness and wear resistance, so they don’t dull out too quickly. 

v. Other Applications

Surgical instruments and implants require heat treatment to ensure they are sterile, biocompatible, and strong enough to perform delicate tasks. In consumer goods, heat-treated components can be found in everything from household appliances to electronics. 

Conclusion 

Improving part longevity with heat treatment is a game-changer for stamped parts. The technique also improves their strength, hardness, and malleability, along with reducing internal stress. The heat-treated stamped parts generally last longer under pressure and stress than non heat-treated parts. 

Looking to make your stamped parts last longer? Zintilon’s got you covered. We offer various metal fabrication services for both custom parts and rapid prototyping. Let’s chat about how we can help you with sheet metal fabrications. 

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