×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Corrosion on cast steel

Corrosion on cast steel

Corrosion on cast steel

(OP)
We are having a larger stock of valve bodies made of cast steel CF3M and corrosion appears due to humidity in our warehouse which can not be decreased. What are you proposed to protect the corrosion? medium should be effective nit exensive and easy to use? Any sugegstions?
How do you remove corrsion from cast steel surfaces?
Thx
J

RE: Corrosion on cast steel

How long do you expect them to stand for? Cosmoline is the original corrosion preventer. Soluble oil in your machining coolant provides some protection after machining. I have found film forming additives used in diesel engine coolants can provide short term corrosion protection without oily residues.

To remove corrosion a quick dip in phosphoric acid will remove light corrosion. Follow up with a rinse in water treated with the aforementioned diesel engine coolant treatments to prevent flash rusting as it dries. The diesel treatment is a supplemental coolant additive or 2000 series coolant treatment mixed 16:1 with water. The active ingredients are sodium silicate, sodium borate, and sodium nitrite. I'm sure there are specific products for your application but I have these abundantly available and they work for me.

RE: Corrosion on cast steel

These are stainless steel castings. The rust spots are either from small surface inclusions from casting or where you have touched them with steel. Lifting or resting them on steel surfaces will embed small amounts of Fe in the surface which will later rust easily.
If these are only on the cast surfaces maybe you should have some words with you supplier. The casting should have been annealed, blasted (usually grit or shot) and then passivated (hopefully in Nitric acid). The raw castings should never show rust spots.
1. If you have done any machining make sure that you coolant is well filtered.
2. If you do any 'touch up' with wire brushes, flap wheels, or files make sure that these are only ever used on stainless steel. (and make sure that the brushes are 3xx SS)
3. You can remove Fe easily with acids, the safest is a product called CitriSurf which is citric acid based. (I have bad experience with a quick dip in anything other than nitric acid, but that is more difficult)
4. Any of the corrosion inhibitor companies will sell Rust Preventive (RP) oils some of which are designed for Stainless Steels, ask.
5. Use nylon slings for lifting, rest only on wood, cardboard, or plastic, use flange face covers (also minimizes mechanical damage). No chains, no metal forks, no steel tables or pallets.

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

RE: Corrosion on cast steel

Ed, if I may ask, how many times have you responded with the same answer to questions very similar to this one? Daily? ;)

Best regards - Al

RE: Corrosion on cast steel

No, only once or twice a week.

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

RE: Corrosion on cast steel

It was a common problem years ago when I worked : A manager would call and say " the stainless you told me to get is rusty and we have not yet used it". I am surprised it is still common.

RE: Corrosion on cast steel

Have you considered dehumidification for your warehouse?

RE: Corrosion on cast steel

Install silica dsumidifiers and spray an anticorrosion vernish on your valve bodies

luis

RE: Corrosion on cast steel

If the cast SS parts are showing rust spots it isn't because of humidity, It is because something was done wrong before.
Storing in dry air will hide the problem, but when they get to the customer they will have rust spots.
Find and fix the root cause.

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

RE: Corrosion on cast steel

Have the castings been annealed? Tip, they should be.
Were they pickled afterwards? They should have been in Nitric Acid/HF.
Avoid contact with and steel, or accept that you will have to acid passivate to clean them before storing.

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

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now
The Great Project Profitability Debate
A/E firms have a great opportunity to lead the world into the future, but the industry’s greatest asset—real-time data—is sitting wasted in clunky, archaic ERP platforms. Learn how real-time, fully interactive dashboards in a modern ERP allow you to unlock data that will shape the future of the world. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close