Product Info

🌟 Key Takeaways
• Shot Peening is a controlled mechanical surface treatment process.
• It improves fatigue strength without altering the internal microstructure.
• Suitable for components subjected to cyclic loads such as gears, springs, and drive shafts.
• It is a mechanical surface treatment, not a heat-based process.
• Performance depends more on process control than on peening intensity.

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In mechanical engineering, many metal component failures do not occur due to a single overload but result from accumulated cyclic loads that initiate cracks and eventually cause fracture. Fatigue damage typically begins at the surface, making surface property enhancement critical to component lifespan.

Shot Peening was developed to address this issue by strengthening the surface layer of metal components. The process involves propelling small media (shots), such as steel shot or ceramic shot, at controlled velocities to uniformly impact the component surface. These impacts cause localized plastic deformation at the microscopic level, generating residual compressive stress on the surface.

This compressive residual stress counteracts tensile stress during service, suppressing crack initiation and propagation. Conceptually, Shot Peening can be described as “compressing the metal surface,” making it more resistant to fatigue cracking caused by cyclic loading.

In practice, Shot Peening extends the service life of components subjected to repeated loading, reduces the risk of sudden fracture, and improves the consistency of engineered surface quality. As a result, it is widely applied to automotive components such as springs, gears, and drive shafts, as well as continuously operating machinery parts and aerospace or safety-critical structural components.

Effective Shot Peening requires proper control of process parameters, including shot size and impact velocity appropriate for the material. Surface coverage must be uniform, and the process is typically performed after machining and heat treatment. Conversely, using excessively hard shot on soft materials can damage the surface, and Shot Peening should not be considered a replacement for heat treatment, as it does not alter the internal structure of the metal.

Common issues include over-peening, which can damage the surface, and non-uniform coverage, which leads to inconsistent mechanical properties. These problems are mitigated by applying standardized parameters and verifying intensity using Almen strips in accordance with industry guidelines.

📘 Summary
Shot Peening is a fundamental yet powerful process for extending the service life of metal components, particularly those subjected to cyclic loading and requiring high reliability. Understanding its principles and proper process control ensures effective and cost-efficient application.

📥 CTA
For deeper technical understanding, DOWA Thermotech (Thailand) Co., Ltd., with expertise in heat treatment and surface engineering, recommends exploring the related advanced topics below.

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❓ FAQ
Q: How does Shot Peening differ from Sand Blasting?
A: Sand blasting focuses on surface cleaning, while Shot Peening generates residual compressive stress to improve fatigue resistance.

Q: Can Shot Peening replace heat treatment?
A: No. It is a supplementary process and does not change the internal microstructure of the metal.

Q: At which stage of manufacturing should Shot Peening be applied?
A: It is generally performed after machining and heat treatment to preserve the desired surface properties.

📚 Glossary
• Shot Peening: A process that propels small metallic media to induce residual compressive stress on a metal surface.
• Residual Compressive Stress: Compressive stress retained in the surface due to microscopic plastic deformation.
• Fatigue Strength: A material’s ability to withstand cyclic loading without failure.
• Cyclic Load: Repeated loading applied to a component during service.
• Almen Strip: A standardized strip used to measure Shot Peening intensity and consistency.

📖 Reference
[1] Shot Peening Overview – ASM Handbook, Surface Engineering
[2] SAE J443 / J442 – Shot Peening Standards – SAE International – [https://www.sae.org](https://www.sae.org)
[3] Industrial Surface Treatment Practices – Automotive Industry Application

🔗 Cluster Internal Link
• Core Content: “Shot Peening | Extending Automotive Component Life and Reducing Fatigue Failure”
• Advance Knowledge:

#ShotPeening #MechanicalEngineering #FatigueStrength #SurfaceTreatment #ManufacturingProcess #ResidualStress #AutomotiveParts #MaterialEngineering #IndustrialEngineering #SurfaceEngineering

📆 Updated: 2025-12-16