Tool Steel - S7 - Surface defects? 1

[qu1nn]

Hello,
Is there a good web site or book which shows pictures of defects that can occur with steels.

For example at work I have seen that after tool steel (S7) has been heat-treated the surface apears to have a rippling, something like I can only describe as a fingerprint or maze as when viewed under a microscope.

More pronounced when microblasting.

Thank you for your time


Qu1nn

 

[MOB1]

Sounds like you could have a scaling problem. You need a protective atmosphere during heat treatment.

 

[unclesyd]

Where there any finishing like grinding done to the part prior to HT?
What was the starting material's condition as received?

We never had any problem with S-7

 

[metengr]

To answer your first question, there is a web site that was originally posted by unclesyd, which I happened to book mark. It is a German web site that includes a section on surface and subsurface defects in steel (with pictures). A hyperlink under material defects will take you to an English version. Very informative.

http://www.metallograf.de/start-eng.htm