Metal stamping uses a variety of metals and alloys to produce high-performance parts with exceptional accuracy and repeatability. When choosing a metal material for a stamped part, it is important to consider its compatibility with the metal stamping process as well as your application.
Factors such as tensile strength, hardness, ductility, and machinability will influence the metal’s ability to be accurately shaped and formed without breaking or losing its strength. In this guide, we will discuss the key factors to consider during the material selection process and some of the best raw materials for stamped metal parts.
Which Factors Are Important?
Choosing the best material for a metal stamping project requires careful consideration of several factors, including:
One of the most important factors to consider is the material’s ability to adequately support your application. For example, stainless steel is often used for plumbing components due to its durability, temperature resistance, and corrosion resistance, while copper is often preferred for electrical components and connectors since it provides high thermal and electrical conductivity.
In addition to performance and appearance considerations, it is important to make sure the cost of the raw material fits within your project’s budget.
A material’s formability describes its ability to bend or deform without cracking or fracturing. ESI’s Bend Rating scale assigns colors to different metals to indicate their level of formability, with green representing the highest formability and red representing the lowest.
A variety of finishes can be applied to stamped metal parts to enhance functional qualities such as strength, temperature resistance, and corrosion resistance. Finishes can also improve the aesthetics of a stamped part by providing them with a smoother, more attractive exterior.
Tensile strength measures a material’s ability to resist breaking when a force is applied. The selected material should provide the required tensile strength to withstand the mechanical stresses it will encounter during use.
The weldability of the material should be considered when welding is a necessary processing step. Soldering materials with low weldability may require advanced tools and techniques, which can negatively impact your timeline and budget.
Machinability describes how easily the material can be cut using machining tools. For stamped parts that will require machining operations, it is important to choose a material that can be machined without the use of expensive specialty tools.
Ductility and Formability
A material’s ductility and formability will influence its ability to be successfully manipulated into certain shapes. For example, ductile materials can be pulled into wires and other thin or elongated forms without breaking.
What Raw Material is Best for Metal Stamping?
There are many raw materials suitable for the metal stamping process, each of which offers its own advantages for various applications.
Copper is a soft, malleable metal that can be stamped in its pure form or combined with various alloying elements to create stamped parts with a range of unique properties. The most common copper alloys include bronze, brass, and nickel silver, all of which can be formed into various shapes to fit specific application requirements. With this versatility, copper and its alloys have become some of the most popular materials for metal stamping. Other benefits of copper-based materials include:
- Corrosion resistance. Copper and its alloys are known for their exceptional corrosion resistance, which comes from the naturally protective film on their surface that reforms after the stamping or finishing process. While all copper alloys provide some degree of protection against corrosion, some are more resistant than others.
- Decorative appeal. Copper alloys are valued for their attractive golden, amber, and yellow tints, making them a suitable option for decorative parts or architectural accents.
- Ductility. With their excellent ductility, copper and its alloys can easily be formed into wires, metal threads, and other thin, intricate components.
- Easy to sanitize. Copper-based materials combine corrosion resistance with a smooth surface finish, making them an excellent choice for creating parts with hygienic, easy-to-clean surfaces.
- Copper also exhibits antimicrobial properties, making copper-based materials ideal for medical and food processing applications.
Steel is a dense, highly durable metal alloy known for its inherent strength and design flexibility. Due to the presence of iron, steel and most steel alloys also exhibit magnetic properties. Benefits of steel include:
- Versatility. Although steel is an alloy itself, it can also be combined with other alloying elements in varying proportions to create materials with enhanced mechanical properties.
- Excellent formability. Steel parts are compatible with a wide range of metal forming processes, including stamping, machining, cutting, forging, welding, and more. This gives manufacturers the flexibility to create a range of intricate or unique metal products.
- Affordability. Steel and steel alloys are some of the most cost-effective material options for stamped parts since they are easy to source and highly compatible with most metal forming processes.
Stainless steels are iron-based alloys with various proportions of chromium in their composition. Although they tend to be more expensive than carbon steels, their superior engineering and mechanical properties justify their higher costs for certain applications. Benefits include:
- Corrosion resistance. Due to the presence of chromium in their composition, stainless steels outperform most carbon steels in terms of corrosion resistance. This makes them a popular material choice for medical and food handling applications. Carbon steels generally require galvanization to provide similar levels of protection against corrosion.
- Attractive finish. Stainless steels provide parts with a smooth, lustrous surface that is easy to clean and maintain.
- Magnetism. Stainless steels are available in both magnetic and nonmagnetic options depending on their microstructure and composition.
Brass is an alloy consisting of copper and zinc in varying proportions. Known for its hardness and malleability, brass is suitable for everything from stamped medical components to locks, bearings, valves, and gears. Benefits of brass include:
- Thermal and electrical conductivity. As a copper-containing alloy, brass exhibits excellent thermal and electrical conductivity.
- Decorative appearance. Brass provides a characteristic bright, golden appearance, making it a popular material choice for creating ornamental hardware and other stamped components where visual appeal is a priority.
- Versatility. Brass is ductile, corrosion-resistant, non-magnetic, and exhibits excellent acoustic and antimicrobial properties. This versatility allows brass to fulfill a range of unique material requirements.
Beryllium copper is a non-ferrous copper alloy often used to create springs, aircraft engine parts, bearings, and other stamped parts that must endure heavy loads or high stress. Advantages of beryllium copper include:
- High electrical conductivity
- High-to-moderate strength alloys
- Corrosion resistance
- Great thermal conductivity
- Compatible with precipitation hardening
- Inherent resistance to stress relaxation
Phosphor bronze is a copper alloy containing varying proportions of tin and phosphorous. The presence of phosphorous gives this alloy excellent fluidity in its molten state, enhancing its castability. Phosphor bronze also has desirable mechanical and chemical properties, providing stamped parts with high resistance to fatigue, wear, and corrosion.
Aluminum is a soft, silvery-white metal known for its high strength-to-weight ratio. This makes aluminum and its alloys well-suited for creating lightweight stamped components that still offer high levels of strength and stability. Other benefits include:
- Excellent formability. Aluminum is extremely flexible and malleable, allowing it to be bent, stretched, hammered, and stamped into various shapes without breaking.
- Thermally and electrically conductive. Aluminum and its alloys are effective thermal and electrical conductors, exhibiting minor resistance or energy loss in the process.
- Resilient. Resistant to both corrosion and low temperatures, aluminum-based materials maintain their resilience in environments where other alloys would become brittle.
- Attractive finish. Aluminum metals provide a naturally smooth and shiny surface that is easy to clean and maintain.
Titanium is a low-density, high-strength specialty material used extensively in demanding aerospace, nuclear, marine, and energy applications. Titanium alloys can withstand some of the most aggressive and extreme environments, but their strength and hardness can make stamping and other metal-forming processes challenging. They also tend to be more expensive than other alloys due to the complex process required to produce titanium.
Precision Metal Stamping at ESI
At ESI, our in-depth engineering experience and cutting-edge automation equipment have made us a leader in custom metal stamping and automated assembly. Our online Material Selector tool simplifies the material selection process, allowing you to quickly identify the best possible material for your application. You can also browse our Material Selection Guides to learn more about various metal stamping materials and the applications they support.