×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Carbon steel case hardening color

Carbon steel case hardening color

Carbon steel case hardening color

(OP)
Hello,

I have a question about the physical appearance of carbon steel after it is hardened with inudction hardening vs carburising. The steel grade is C45.

The reason for question is we have parts with indication of induction hardening to 52 HRC on design. I control it with a portable hardness tester, but one of my colleagues was saying that it is enough to see the part visually, if it appears balck and the black layer can not be removed by abrasive paper it is hardened, if the black layer goes away by abrasive paper it is not hardened enough.

I find this a bit strange criteria for QC of hardening process. Maybe he is confusing it with carburising process?

RE: Carbon steel case hardening color

It is actually not that strange, it's just not very quantifiable.

I used to do a lot of macro etching on steel welds and I could pretty reliably tell you which pipe had the higher carbon content by how dark the HAZ etched.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

RE: Carbon steel case hardening color

The problem with induction is that changes in weather (temp and humidity) will change the appearance of the surface.
And carb colors can change with the cool down process which has no impact on the actual case.
It might work for a short time span, but I wouldn't trust it overall.

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

RE: Carbon steel case hardening color

Nashanas
it depends on the requirement of the product.
commercial or aerospace , makes a difference.
for aerospace requires hardness testing
edit also add if required for safety reasons, under loads
visual will not suffice.

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

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