Effect of sand blasting on the SS304 stainless steel plate. 1

[replica]

Hi all,

Does anybody know about the effect of sand blasting on the SS304 stainless steel plate to remove oxide scales? I had come across on the procedure of shot peening on the internal surface of tube (in contact with steam) was implemented by the boiler tube manufacturer to improve the corrosion resistance of the internal tube due to the diffusion/migration of chromium to the shot peened surface. But I do not know if sand blasting will have the same affect as shot peening. As far as I know sand blasting will reduce the corrosion resistance at the surface due to deformation.

Any comment will be appreciated.

 

[dik]

can you find a better way of cleaning it? sand or steel shot can cause rusting and pitting issues...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Dhurjati Sen]

Sand blasting has been banned in most parts of the world. Did you mean shot / grit blasting?

DHURJATI SEN

 

[replica]

dik
Can you find a better way of cleaning it?
I do not know. The best method is probably acid cleaning but it is impractical for the big plate. Blasting probably the last option.

Dhurjati Sen
They blast using garnet. Does blasting using garnet will affect the corrosion resistance of SS340 plate?
Blasting is used to remove the oxide scale and shot peening with steel ball is the surface modification process to improve the properties of the steel especially fatigue and also to increase the corrosion resistance of SS304. This is what I understand.

 

[EdStainless]

What is usually done is the surface is blasted with shot to break scale, and then it pickled (mixed Nitric HF) to remove the scale and Cr depleted zone.
If you sandblast with garnet (natural SiO2) the embedded sand itself is no problem, but you will be embedding pieces of oxide also.
In dither case you need to pickle afterward.
Some people have claimed that the shot blasted surface is smoother and somehow better, but I have never seen it proven by corrosion testing.

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P.E. Metallurgy, consulting work welcomed

 

[bobjustbob]

When processing stainless castings, CF8 would be the cast equivalent. Our final process was to blast with garnet to remove any residual free iron embeded on the surface. Valve manufacturers hate to see rust on their stainless valves after sitting in their yard for a bit. The garnet could only be used once due to the iron contamination in the grit.

Bob

 

[dik]

ES... answered it using nitric acid to passivate...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[EdStainless]

Bob, good point about the blast media being one use. This isture if you are not chemically passivating (cleaning).
Nitric acid is fast and thorough at Fe removal.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed