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I am an engineering student who is working on a project. One of the things that will make the project a success is I need to know how to join a very thin type 304 stainless steel wire loop onto a slightly bigger high carbon steel pole in a very efficient way and can do it in an industrial scale. I know high carbon steel has low weldability and it is the interest of this project that the strength of the carbon steel and the ductility of the stainless steel(its softness) are not undermined.The mechanical shop in my school doesn't know anyone that is involved with these processes. So could you guys help me out here?

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    $\begingroup$ Low weldability does not mean that it is impossible to weld. $\endgroup$ – hazzey Nov 5 '16 at 4:48
  • $\begingroup$ However, I would like the process to be quick and industrially profitable $\endgroup$ – Faito Dayo Nov 5 '16 at 13:40
  • $\begingroup$ I would recommend looking into how they connect springs to the back of unistrut nuts. There's a slot that the wire is inserted into, and then the nut metal is crimped or pressed around it. I'd imagine it would work equally well with your materials as long as your high carbon steel is modestly ductile. It must be industrially efficient because they make millions of the nuts and they aren't too expensive. $\endgroup$ – Ethan48 Nov 8 '16 at 14:24
  • $\begingroup$ How hard is the carbon steel ? If it is at maximum hardness , any heat ( eg. 400 F ) will begin softening it. Can you use the standard soft steel slug that is normally crimped around small steel cables to hold them ? $\endgroup$ – blacksmith37 Apr 10 '18 at 15:05
  • $\begingroup$ Wire rope, carbon steel or stainless, is normally cold worked to a high strength. So unless you annealed the stainless, it is not "soft and ductile". If not already annealed, the stainless could lose 80 to 90 % of its strength when heated. $\endgroup$ – blacksmith37 Apr 10 '18 at 15:57
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Taking the question in isolation resistance welding and forge welding are potential techniques for joining dissimilar materials in mass production and for very small items vacuum brazing is often attractive.

Having said that if your main consideration is to achieve a malleable eye then joining two materials may not be the best option. Firstly stainless steel isn't especially ductile compared to carbon steels and if anything it tends to be more difficult to cold work ( I speak from experience here).

Probably a better solution is to deferentially harden the needle as a plain carbon steel can provide both high strength and hardness and reasonable ductility depending o how it is worked and heat treated and it is certainly possible to have a needle which is hard at the point and soft at the eye.

A simple way to achieve this is to start with annealed stock (which you would anyway as needles are generally drawn to shape) and either heat the whole thing and just quench the point or just heat the point and quench the while thing. either approach is reasonably viable for mass production.

You can also consider that different steel alloys have variable hardenability, ineed the standard test of hardenability is quite close to what you want to achive. So you might want to focus some of your research efort on selecting a steel grade with hardening cahractersistics which best suits this apllication. With care you shodl be able to arrive at a method which goves you a very hard point, a tough shaft and a ductile eye.

I would also add that even if your design concept is a bit flaky (which it is) this sort of research will still make the project worthwhile and stand you in good stead for your future career as you will learn much about steel alloys and their processing and heat treating.

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  • $\begingroup$ Sir, do you mean just quench the point and leave the rest of the part cool down naturally? $\endgroup$ – Faito Dayo Nov 13 '16 at 2:10
  • $\begingroup$ Also, is it possible to heat just the point and the body without heating the eye through the use of conveyer belt? $\endgroup$ – Faito Dayo Nov 13 '16 at 2:16
  • $\begingroup$ Also, could you please tell me what do you mean by stainless steel is harder to cold work? I am only thinking of using the same type of stainless steel as those used in threader. they are very soft $\endgroup$ – Faito Dayo Nov 13 '16 at 2:19
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You forge weld it. I watch Forged in fire and this is done regularly.

https://www.bladesmithsforum.com/index.php?/topic/31392-forge-welding-stainless-and-fire-pattern-damascus-wip/

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