Rusted steel connection

[BAGW]

Hi,

What are the methods for cleaning rust off a structural steel? Is sand blasting way to go?

Is there a testing method out there to verify the strength of the steel subjected to rust?

Thanks

 

[EdStainless]

The real question is how much solid steel is left after removing the rust.
In many cases it is too little to consider suitable for the use.
Chipping, needle guns, blasting will all remove rust.
It largely depends on access and size.

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P.E. Metallurgy, consulting work welcomed

 

[JAE]

We've typically required shot blasting to remove the rust and surface scale - getting it down to competent solid steel - you can usually tell with the eye.

Then measure the remaining thicknesses of flanges and webs and compare with the original specified thicknesses for the shape in question.

This gives you essentially a reduced section with reduced properties that you can check via calculations whether your section is still adequate.

 

[Tomfh]

It all depends on the situation. Rotary wire brush, grinder, needle gun, sand blast, etc are all common methods.

 

[RPGs]

In some cases, it doesn't need to be more than a $5 wire brush to get an idea initially. I worked on a project where we thought the rust wasn't too bad, but a simple wire brush cleaning revealed the section was completely perforated. Very exciting stuff. Getting clean down to bare metal can require a lot more effort, but the thoroughness of the required cleaning will depend on your repair method and if you'll be coating the steel afterwards--repaired or not. I was surprised to learn that some coating compounds don't require much cleaning past removing loose rust, paint, and dirt, but it obviously depends on what kind of corrosion resistance you need. I've worked with Sika before and they are very helpful in recommending a coating for the application.