Stress risers are crucial to identify and address using force such as shot peening or shot blasting. The key is understanding which process to use in each situation to prevent stress risers from compromising your equipment.
Why Do You Need to Address Stress Risers?
When a piece of material has a stress riser, it results in a localized increase of stress in the area, which can cause a crack to spread.
In respect to machining and forming metal parts, stress risers exist internally, causing additional defects to material such as steel, glass, or ceramic when the material is burned, scratched, or welded.
These common stress issues may be responsible for premature fatigue failure, fretting, permeability, deteriorated strength, and corrosion.
Shot blasting is used primarily to rid metals of corrosion and rust, while shot peening is the preferred method to toughen metal and increase its strength. Shot peening, which is often confused with abrasive shot blasting, helps improve residual surface stresses to enhance long and intermediate fatigue life.
Both processes have significant advantages to address stress risers. Shot blasting works at excessively high speeds to remove unwanted elements, while shot peening allows for more control and has significant effects on the fatigue properties of surfaces or parts.
When Should You Use Shot Blasting?
Shot blasting uses the streamlined force of abrasive materials onto a surface to smooth or prepare a surface for further processing.
This process may be necessary to ensure a coat of paint adheres properly to the surface; it can also help clean off contaminants, like grime or grease, and remove rust or mill scale. Enabling the rapid elimination of surface impurities helps speed up a project.
As part of the process, a wide variety of abrasives can be used – and re-used in some cases – including gentle abrasives such as baking soda, extreme abrasives such as aluminum oxide, and other abrasives such as glass, plastic, and magnesium oxide.
The benefits of shot blasting:
- An inexpensive method to prepare and clean surfaces.
- Various blasting methods available to remove surface deposits.
- Variety of abrasives to prepare surfaces.
When Should You Use Shot Peening?
Shot peening is cold-working process specifically designed to improve the fatigue resistance of components that have been subjected to stress. The shot peening process enables the surface of a part or material to be modified by impacting it with tiny metal balls of steel. These “shots” form small indentations on the surface with enough force to sufficiently strengthen and relieve stress in the components.
Shot peening can be used on a broad range of engineered parts from cars to oil rigs. Additionally, shot peening machinery is capable of processing a variety of parts of different shapes and sizes with precision and accuracy.
The process allows engineers to design products in a smaller platform and use thinner wall sections due to the compressive residual stresses that help prevent cracking on more fragile material. Steel shot peening extends a longer life profile than glass or ceramic, and it is available in carbon steel and stainless steel to achieve high intensity.
Similar to shot blasting, there are many abrasives for shot peening, including baking soda, glass, or plastic bead, aluminum, and magnesium oxide.
The benefits of shot peening:
- Improves fatigue life
- Prevents cracking due to wear and tear
- Inhibits hydrogen embrittlement, fretting, and galling
- Can be used to curve metal or straighten shafts without causing tensile stress
Learn More About the Superior Shot Peening Process
Both shot blasting and shot peening are proven technology to help deburr, clean, and enhance appearance. The main difference is that shot peening improves the overall fatigue life for a variety of parts.
Superior Shot Peening has developed a proprietary shot peening process that hardens and smooths the appearance of metals, plus improves durability and lengthens life by addressing stress risers.
With over 50 years of experience, we have peened almost every commercial metal on the market. Our knowledgeable and experienced team understands the importance of controlling the environment to prevent oxidation failure issues when preparing metal surfaces.
Superior Shot Peening is dedicated to the highest quality output and the fastest turnaround. Contact us today to learn more about our unique process and how we can extend the life of your equipment.
