What is Shot Peening? Benefits for High-Performance Spring Action

With more than 170 years of spring expertise, Lesjöfors combines advanced manufacturing processes, state-of-the-art machinery, and engineering know-how to deliver precision springs of the highest quality. Our production capabilities span the latest hot and cold coiling technologies and surface treatments such as shot peening to ensure consistency, durability, and performance.

In this blog, we’ll explain what shot peening is, how the process works, the key benefits for spring performance, and why it remains a cornerstone of advanced spring manufacturing.

Shot peening is a cold working process that bombards a metal surface with spherical media – commonly steel, ceramic, or glass beads – at controlled velocity. Each impact creates a small indentation, introducing beneficial compressive stresses on the material’s surface layer.

By doing so, the process counters tensile stresses that typically lead to fatigue cracks. This makes components like springs significantly stronger and more resistant to failure. It’s widely recognized across engineering disciplines as a strengthening method.

The shot peening process relies on kinetic energy. As spherical media impacts the spring surface, each strike plastically deforms the top layer of the material. This repeated bombardment creates beneficial structural changes that significantly improve spring performance:

The depth and intensity of the compressive layer are carefully controlled by parameters such as shot size, velocity, coverage rate, and impact angle. Engineers measure peening intensity to ensure process repeatability and compliance with international specifications.

Modern computer-controlled equipment regulates these variables with precision, ensuring consistent coverage even on complex spring geometries. This consistency minimizes variability between parts and guarantees uniform performance in large-scale production.

The shot peening process has been extensively documented in material science research, confirming the link between residual stress formation, fatigue life extension, and overall reliability. The result is a method that strengthens springs, delivering predictable and measurable durability.

As the most common media in spring manufacturing, cast steel shots provide strong impact energy and uniform results. They’re ideal for high-strength steels and heavy-duty applications, and they can be recycled many times before degradation, making cast steel shot peening cost-effective for large-scale production runs.

Ceramic beads are lightweight yet durable, used where minimal contamination is required, particularly in aerospace or medical springs. They also withstand high operating temperatures, making them suitable for turbine engine springs and other heat-exposed components.

Glass bead peening delivers a smoother surface finish while still providing compressive stress. It’s often applied to springs where aesthetics and corrosion resistance matter. This method is also used in medical applications where smooth surfaces are required to prevent bacterial adhesion.

Cut wire shot, made from chopped wire pieces, offers consistent size and density. This precision makes it ideal for components with tight tolerances. It produces minimal dust and maintains a consistent spherical shape during use, ensuring reliability across multiple cycles.

Less aggressive than metallic or ceramic media, plastic shot is used for delicate components or softer alloys where minimal surface removal is critical. Plastic peening can also be applied as a finishing stage after metallic peening to refine surface texture without compromising compressive stress.

For high-performance spring applications, shot peening offers a range of distinctive advantages as a surface treatment.

Fatigue improvement is one of its most recognized outcomes of shot peening. Springs with this surface treatment can withstand millions of stress cycles, extending service life dramatically.

The compressive stresses help springs resist cracking caused by movement and extreme and corrosive working environments. This makes the process indispensable in offshore drilling rigs, heavy duty equipment, naval defense equipment, as well as subsea robotics, where components are continuously exposed to demanding external environmental pressures as well as saltwater and corrosive agents.

Even when microscopic flaws are present from manufacturing or operational wear, shot peening dramatically slows their progression, giving engineers valuable safety margins.

Shot peening reduces surface imperfection variations and hardens the material surface, lowering frictional wear. This effect reduces maintenance intervals and operating costs in sectors like heavy machinery and mining.

By increasing fatigue strength, springs can be designed with less material while maintaining performance, optimizing weight for aerospace, automotive, and medical devices. Lighter springs not only improve efficiency in automotive applications but also support fuel economy.

Within aerospace and defense sectors, shot peening is used to increase fatigue resistance and safety assurance in landing gear, turbine springs, and actuation systems. Examples include helicopter rotor springs, missile guidance actuators, and control surface return mechanisms, all of which must function under high cyclic loads.

From suspension springs to transmission components, shot peening ensures reliable performance under the vibration and cyclic loading of automotive and transportation applications. Shot peening is also applied to clutch springs, valve springs, and is an essential manufacturing process behind vehicle suspension systems.

Within energy applications, valve springs, nuclear power components, and oilfield equipment benefit from improved fatigue strength and resistance to stress corrosion cracking. Wind turbine springs, geothermal valve components, and pressure control springs in gas pipelines are other examples where shot peening prevents premature failure.

Precision springs in surgical tools and implants require both fatigue strength and biocompatibility, achievable through ceramic or glass bead peening. Applications range from pacemaker springs to robotic surgical instruments, where reliability is critical to patient safety.

Industrial machinery, robotics, and construction equipment depend on shot-peened springs for consistent performance under demanding conditions. In robotics, peened springs help maintain consistent motion cycles, while in construction, they provide resilience in hydraulic systems subject to shock loading.

Shot blasting cleans and prepares surfaces, removing scale or rust. Shot peening, by contrast, is about introducing compressive stress to improve fatigue strength.

While both use high-velocity media, blasting is primarily a cleaning process. Engineers can perform blasting before peening to remove scale, ensuring maximum effectiveness of compressive stress induction.

Laser peening uses high-energy lasers to create shock waves on the material surface. It penetrates deeper than shot peening, which is more complex and can be costly. Shot peening remains the cost-effective choice for most spring applications. .

Ultrasonic peening uses vibration and small hammers to induce compressive stress. While precise, it’s slower and less scalable compared to shot peening services for large-volume production.

At Lesjöfors, we go beyond advanced spring design to deliver a comprehensive range of manufacturing technologies and surface treatments, including shot peening, heat treatment, and surface coatings. These processes are tailored to meet the toughest demands in aerospace, automotive, medical, and other high-performance industries.

Shot peening is one of the most effective methods for extending fatigue life and ensuring springs perform under extreme conditions, and it remains central to our manufacturing expertise. By partnering with Lesjöfors, you gain access to state-of-the-art processes that guarantee optimal strength, reliability, and performance.

Contact us today to discuss your spring requirements and learn how our technologies can deliver the results you need.