Contact US

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 prevention

Corrosion prevention

Corrosion prevention

Is corrosion measureable/quantifiable? Also, is there a recommended minimum thickness of zinc on steel for parts in a high temperature and high humidity environment for extended periods?

Thank you for your time,

RE: Corrosion prevention

Regarding recommended thickness of zinc on steel parts, according to ASM Materials Handbook, they suggest somewhere in the range of 0.001 to 0.002 in for severe environmental condition use. This will provide an extended service life over a thinner coating (say 0.0002 to 0.0005 in) The handbook also suggests "zinc plated steel in such locations is usually given a protective coating of paint."

With regard to whether corrosion is measurable/quantifiable, I do remember having read something about that somewhere, but I am unable to prove or suggest any possibilities there.

Best Regards,

Paul Rivet

RE: Corrosion prevention

Hello Paul:

Thank you for you response, i appreciate it.

Steve DeLucia

RE: Corrosion prevention

Yes, Corrosion is measured (for uniform corrosion) as corrosion rate in the unit "mpy (mils per year)" and can be calculated using the following formula

mpy = 534W/DAT where
W= weight loss, mg
D = density of specimen g/cm3
A= area of speciment sq.in
T = exposure time, hr.

For ferrous alloy corrosion rate < 20 mpy is good, 50-200 mpy is poor and > 200 mpy is unacceptable.

As for the thickness of zinc coating according to AS1650 for steel is as follows:
coating mass( gm/m2) eq. thickness (um)
steel over 5 mm thick 600 84
steel between 2-5 mm 450 63
< 2mm thickness 350 49

The rule of thumb is that the thicker the zinc coating, the better protection you have. I agree with Paul that a duplex system (zinc galvanized + paint) is better for such environment. But you have to keep in mind that a special surface preparation and paint is needed or else the paint will not adhere to the zinc coating.

Surin Tan

RE: Corrosion prevention

Hello Surin Tan:

Thank you very much for taking the time to respond to my question. Have a great weekend.


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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
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

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