Questions regarding a hardening process

Apr 13, 2004 3 Replies

Hi all, i found your group through google, i am a mechanical engineering student at RIT and i am having problems with an assignment i was given so i was wondering if you all would be able to provide some input as i am at a lack of where to go with this.


Design a process to produce a 0.5-cm-diameter steel shaft having excellent toughness, yet excellent wear and fatigue resistance. The surface hardness should be at least HRC 60, and the hardness 0.01 cm below the surface should be approximately HRC 50. Describe the process, including details of heat-treating atmospher, temperatures, times, and composition of the steel


any help with this would be greatly appreciated



Greg


I second that. ;)

Greg, post some of your research here and get it critiqued might work? You've got to know... that about every other week someone posts here asking for others to "do their homework for them".

I'm wondering if... "help with your homework" wouldn't fly tho. :)

That'd be fun for me to read at least. :)

Funny but a book I read part of "at someone else's school library" (since i wasn't going to school;) was about automotive related steel metallurgy and the section I was most interested in was the leaf and coil spring, problems and alloys.

They figured if the spring was more than slightly harder on the outside, than the inside, it would develope fatigue cracks etc...

So the important point of the chapter was about alloying and to match the alloying with the thickness of the spring for hardenability. They were targeting ~48hrc.

At least that's what this dumb railroader got out of it. ;)

A lot like your assignment except for the hard outer carbon case for wear resistance?

Alvin in AZ (hobby knife maker/fixer)

Hi Greg!

It looks like RIT has their Materials Processing course (343) before their Materials Science course (344). Odd, that, but it would explain your confusion.

Your assignment is crying for a case hardening process. As Sporkman suggested, induction hardening would be appropriate. I would lean more towards nitrocarburizing or carbonitriding (BTW, there's a BIG difference between them). Use a book, not the Web, it'll be faster. I'd suggest ASM Handbook Volume 4 on Heat Treating.

You've also got some fine faculty at RIT. If Bob Snyder is still around, he certainly knows his stuff on this topic. If would also appear that Dr. DeBartolo would be an appropriate person to ask. If they are doing what you, the student, are paying them for, they won't tell you the answer, but will lead you in the right direction.

Good luck!

gearloose

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