×
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!
  • Students Click Here

*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

Jobs

Induction Hardened Steel Surface Etch Pattern
2

Induction Hardened Steel Surface Etch Pattern

Induction Hardened Steel Surface Etch Pattern

(OP)
I have seen two applications where the induction hardened surface of an alloy steel part of round cross section has a distinct circumferential pattern when polished and etched with Nital.  
One of these applications was a press brake roll which I observed some years ago.  The etched surface showed bands of dark and light.  The light bands were approximately 6mm wide and the darker etched bands approximately 2mm wide. Can anyone enlighten me as to the induction hardening process which produces this pattern?

RE: Induction Hardened Steel Surface Etch Pattern

It is not clear to me as to whether you are describing the surface of the roll or a metallographic cross section. For what it's worth, the surface of cylindrical parts that have been induction hardened using a scanning process rather than single shot will exhibit striping or "barber pole" effect on the surface.

RE: Induction Hardened Steel Surface Etch Pattern

The surface etched pattern is the hardened zone. A 6mm is a 3 kHz depth. When using induction we refer to kW's and kHz the kW is how much power & the kHz is how deep it heats.

Also can get good results using a sand/glass bead or steel shot if acid is not desired.

The bands you see on the surface are the barber pole which the previous responder refers to. This is caused by the scanning motion and rotation that occurs during progressive hardening. Kinda like a prequenched area, only a few .002" thick, usually cleans up with grinding.

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!


Resources