Steel Strength vs Toughness

[@nobuckle40]

As a former machinist these two factors we always under consideration. The material determined the tooling use to machine it. These are topics that most people never consider unless it is their profession to do so. Thank you.

[@Shane_at_SteelImage]

@nobuckle40 Agreed - ones awareness of toughness depends quite a bit on their experience. Hoping this video will help make it a bit more mainstream why we often avoid steels with ultra-high strength, at least when toughness is needed. As an add-on to the conversation, we also prefer a moderate-to-high tempering temperature not just for toughness but also to make it reasonable to machine. I'm sure as a machinist you've run across the odd design where someone needless choose a difficult to machine steel condition.

[@lindyengineer]

Great summary. I agree we need to understand toughness better.

[@Shane_at_SteelImage]

Two like minds!

[@terry9397]

Thanks for the explanations and data points. Really good information.

[@Shane_at_SteelImage]

You got it. And thanks for mentioning the data - took me a long time to put together the tensile and Charpy data for this!! But truthfully I did it for my another book I'm working on.

[@RainyDayForge]

I'm interested in tempering embrittlement. Some of the higher tempering temperatures on the graph seemed high and I thought could cause embrittlement. (I'm still learning...)

[@Shane_at_SteelImage]

There are two embrittlement mechanisms that sound close to one another - (1) temper embrittlement and (2) temper martensite embrittlement. The former takes years or decades to occur. The latter, 'temper martensite embrittlement' can occur during heat treatment - so its probably the one you're interested in. It can occur from tempering at temperatures below 750C (

[@Moock91]

Ditch the imperial system and let's use the metric system x) Very interesting tho!

[@Shane_at_SteelImage]

@moock91 most of my experience is with imperial units.Hopefully the trends still pop.