People often mix up two metal surface treatments: shot blasting and shot peening. Both shoot tiny particles at metal, but honestly, they’re pretty different in what they do.
Shot blasting cleans and preps metal by stripping away rust, paint, and junk, while shot peening actually strengthens metal by creating stress patterns that boost fatigue resistance. If you get this basic difference, picking the right process for your project gets a whole lot easier.
Your choice here can totally change how a metal part looks or performs. Each process needs its own gear, materials, and know-how, so it’s worth figuring out which one fits your needs.
Core Differences Between Shot Blasting and Peening
Shot blasting strips away surface stuff to clean and prep, while shot peening is all about making metal tougher. They use different pressures, materials, and methods for their specific goals.
Definition and Purpose
Shot blasting is about cleaning surfaces. It takes off rust, paint, scale, and other gunk from metal. This gets things ready for a new coat of paint, some welding, or whatever’s next.
The main idea is removing stuff, not improving the metal itself. Shot blasting leaves a rough, clean surface that coatings can really grab onto.
Shot peening, though, is a different animal. Instead of just cleaning, it makes metal stronger. Workers fire small metal balls at high speeds to dent the surface a bit, putting it under compression.
This compression helps block cracks from forming. It seriously boosts fatigue life, so parts can handle more stress before giving out.
Process Overview
Shot blasting throws a lot of abrasive material at moderate speeds. The impact and scraping action knock off unwanted stuff. Usually, this happens inside a chamber or blast room.
The particles smack the surface and bounce away, taking rust or paint with them. You end up with a rough, clean finish that’s ready for more work.
Shot peening is more precise—think tight control over pressure and speed. Studies even show shot velocity ties directly to peening pressure and the angle of impact. Workers have to nail the right speed, coverage, and intensity.
Unlike blasting, peening doesn’t strip away much material. It changes the surface structure, making the metal tougher instead.
Materials Used in Each Method
Shot Blasting Materials:
- Steel grit (sharp, cuts through coatings)
- Steel shot (round, leaves a smoother finish)
- Sand (cheap, but it gets dusty)
- Glass beads (gentler on fragile stuff)
Shot Peening Materials:
- Steel shot S230 and S110 (different sizes for different jobs)
- Ceramic beads (won’t mess up sensitive metals)
- Glass beads (lighter touch for thin materials)
- Cut wire (keeps its shape and hardness)
Blasting materials focus on cutting and scraping. They wear out and need swapping pretty often.
Peening materials need to hold their shape and stay hard. The idea is to deform the metal just right, without too much wear or contamination.
Applications and Outcomes
Shot blasting and shot peening really aren’t interchangeable. Blasting removes stuff from the surface, while peening beefs up the metal itself.
Industrial Uses
Shot Blasting Applications:
- Stripping paint and rust off metal
- Prepping surfaces before painting or coating
- Cleaning castings and forgings
- Removing scale from steel
Auto factories use shot blasting a lot—think cleaning car parts before they hit the paint booth. Shipyards blast old paint off hulls too.
Shot Peening Applications:
- Aerospace parts like turbine blades
- Automotive springs and gears
- Medical implants, especially titanium ones
- Aircraft landing gear
Aerospace folks peen critical parts to keep cracks at bay, especially in jet engines. Medical device makers also peen titanium implants so they hold up better.
Surface Finish and Mechanical Properties
Shot blasting leaves a rough texture behind. That roughness gives paint or coatings something to stick to. It gets rid of surface junk, but it doesn’t make the metal stronger underneath.
Shot peening, on the other hand, puts compressive stress into the surface. That stress makes it way harder for cracks to start or spread.
Peening also tweaks the metal’s crystal structure. The surface layer ends up tougher and more fatigue-resistant. Parts that get peened usually last a lot longer under repeated use.
Peened surfaces come out with a matte look. Sometimes, you’ll need to polish them up a bit for certain uses.
Advantages and Limitations
Shot Blasting Benefits:
- You can clean big surfaces pretty quickly.
- It strips off stubborn coatings and rust with ease.
- Great for prepping surfaces before you add new coatings.
- This method works on all sorts of different metals.
Shot Blasting Drawbacks:
- It kicks up a lot of dust and debris—definitely messy.
- Thin materials might get damaged if you’re not careful.
- It won’t make the metal any stronger.
- You really need good ventilation for this process.
Shot Peening Benefits:
- Parts can last 300-500% longer after shot peening. That’s impressive, honestly.
- It helps prevent stress cracks from forming.
- You can use it on parts with complex shapes, which is handy.
- No need for heat treatment, so it’s a bit simpler in that way.
Shot Peening Drawbacks:
- It’s pricier than shot blasting, unfortunately.
- You have to control the process carefully—no room for guesswork here.
- Very soft metals might not respond well to it.
- Sometimes, the surface ends up rougher than you’d like.
