tooling spring steel

[Topher]

I'm considering purchasing some 4130 alloy steel tube for a project. Is this spring steel and with such a high carbon content can it be tooled? It needs to be cut, threaded, and bent to hold its shape. Do I need to bring it up to austenite stage first and if so what would be the temperature and how long do I need to keep it there?

[RWOLFEJR]

Hi and welcome to the forum.
4130 is considered more of a medium carbon steel. It's not a spring steel but it's pretty tough stuff. It machines very nicely. If you're threading it in a hardened state you'll need a good tap or die but turning or boring it hard is piece of cake. You will probably have a hard time buying it pre-hard in tube form. That to say... if you're looking for its highest strength you might need to heat treat it. If you're bending it this complicates things some. You will need to do your finish machining and threading after heat treat (if you need the added yield etc... ) so odds are you'll need to bend it after the machining and therefor bend it hard. It'll bend fine to a point... but you'll need a little more tonnage. If you're flattening then this changes things...

A sketch could help...

Far as you heating the part goes.... Are you planning on heat treating this yourself? If so I can give you some temps etc. and tempering temps and times, but sometimes it's best to let a heat treating house handle it if you aren't really equipped to do it. Heat treating houses have means to reduce distortion and they do this stuff everyday. It's not very expensive to have done.

Good Luck,
Bob

[Topher]

Hi Bob,

Thank you for answering my question. I'm wrestling with a damaged vestibular system I got three years ago when my surfboard hit me in the face. I was fully disabled for over two years, but now I'm starting to recover, slowly, so you'll have to have patience with me. Basically, I'm starting from scratch at 50 and I still can't work full time. I have an idea for a type of fastener but I would like to make a fully functional prototype before launching into the patent process. The 4130 was the only 3/16" O/D tube that I could find and the supply house was unable to tell me if it was spring steel or not, but it was all they had. If it's possible to find spring steel tube in that dimension, would it be possible to bend it myself and have it retain the bend, and if so, where might I look for something like that? If not, could you recommend a fabricator that would work with specialty steels of small dimensions? Topher

[Kelly_Bramble]

Topher, check the following on spring steel: http://www.engineersedge.com/materials/spring-steel.htm

You might consider searching the internet for "standard steel tube sizes". If you have a component manufactured, there are custom tube manufacturers available throughout the country. You will need to supply them with the desired material specifications and end-item dimensional size and tolerance data.

BTW, I don't think 4130 or any 4000 series steel tube is very bend-able, at least no accurate and with tight angle bends.

[jboggs]

I've been doing this for a long time, and I cannot ever recall hearing of "spring steel tube". Considering how special spring steel is to begin with I would be curious to see how it could be fabricated in a tubular shape.