Question on L6 spec. sheet

[Michael Pikula]

I was looking over the spec. sheet for L6 ( http://www.crucibleservice.com/eselector/prodbyapp/tooldie/champloy.html ) and I noticed that it looks like L6 will have less toughness when tempered at 500degrees then it will at 400 or 600. Any thoughts as to why this would be the case?

As a side note I also noticed that there will be less length change when tempered at 400degrees then there would be at 300 or 500. This part doesn't matter too much to me but I always thought that these types of factors move in a more linear fashion rather then "jump" around.

 

[Michael Pikula]

I called up on of the techs. and he wasn't sure so he made some calls and he said that L6 suffers from a mild form of getting brittle when tempered to 500 degrees and they recommend tempering above and below 500 degrees. I thought it was interesting and wanted to pass it along.

 

[fitzo]

Google "temper embrittlement" for some reading on the topic.