Magnetic Stainless steel

[p111dom]

I know there are different graded of stainless steel, varying in quality and that the lower grades can be magnetic. I have a need for some chrome like finished metal that will not tarnish after polishing but is magnetic. Chrome plated stuff is no good as the finish needs to be able to be engraved. Just need thin stuff, 1mm. Does anyone know what grade I need for this and where I could get some. Its for an interior project so lower grade rusting issues shouldn't be a problem.

 

[CNC Paul]

Would it be possible to back it with magnetic rubber ?

 

[p111dom]

Not really. You can definately get it. My SS Smeg cooker hood is very magneitc.

 

[Jake]

I think you want martensitic or ferritic ss.

 

[Steve (Correze)]

420 and 440 will generally be magnetic, normally used for knife blades.

In fact, most "stainless" knives are magnetic, as "true" stainless won't take an edge.

They will rust under certain conditions though, particularly 440C

 

[p111dom]

Thanks. I think I've found a supplier locally of 430 grade SS which hopefully will do. I just hope that its less corrosive resistance properties means that it tarnishes.

 

[9fingers]

Check with whoever is going to the engraving that they are happy to work in your chosen grade of stainless. Some of it is really evil to work with.

Bob

 

[p111dom]

Thats true. The local engravers said they couldn't do it but not bacause of the reason you might think. They recon that most places (including themselves) do laser engraving these days so its not a case of the tooling being not up to the job but the laser not being powerful enough. I didn't know that. I guess I'm a bit behind the times.

 

[wizer]

Dom I could do with a strip of this. About 2m long by 30mm wide. Can your supplier cut to size?

 

[p111dom]

Maybe Tom. I managed to ring them before they closed. Said they only do full sheets of 8x4 but when I explained what it was for he said if I popped along, he would try and sort out some off cuts. I'm needing 4 pieces about an inch wide, 9 inches long and 1mm thickness. I'm also needing 4 pieces 2 inches square by about 5-8mm thick; but those bits don't have to be magnetic. He says they also cut and polish for a price. That might be worth it for me too. I need to check out the engraving issue but assuming that's ok, I'll pop along tomorrow and see if he has any long lengths. Might be a pain to ship though.

 

[wizer]

The width for me is not particularly important and the length is better off about 1400-1500mm

If it's hassle then don't worry. I'm sure I can source some local somewhere.

 

[CNC Paul]

Thats true. The local engravers said they couldn't do it but not bacause of the reason you might think. They recon that most places (including themselves) do laser engraving these days so its not a case of the tooling being not up to the job but the laser not being powerful enough. I didn't know that. I guess I'm a bit behind the times.

The main problem with laser engraving is the reflective properties of the metal.....You do not want lasers bouncing about.

They can get over it with a special non-reflective coating.

 

[p111dom]

I don't know how its done. I thought it would be like mini CNC with Proxon sized cutters but apparently not. All I can do is ask several places and see if anyone can help.

 

[CWatters]

Perhaps put this stuff under a layer of stainless..

http://www.tinytintroops.co.uk/Bases/Fl ... sheets.htm

I believe it's used to stop toy soldiers being knocked over.

 

[Jenx]

Martensitic stainless steels are not as corrosion-resistant as the other two classes (The Ferritic & Austenitic Grades ) but are extremely strong and tough, as well as being highly machineable, and can be hardened by heat treatment. Martensitic stainless steel contains chromium (12-14%), molybdenum (0.2-1%), nickel (0-<2%), and carbon (about 0.1-1%) . thus giving it more hardness but making the material a wee bit bit more brittle. It is quenched and magnetic.

The most common Martensitic grade I come across in the manufacture of Valves and usually more specifically the 'trim' ( the internal guts of the valves ) is 17-4PH Grade. ... common in the stems / trunnions of larger valves and used in the non-rotating tips of instrument needle valves for example. of the top of my head, I'm not 100% certain if 17-4PH is particularly magnetic, but I'll find out for you.. if you can hang in till monday.

As with most stainlesses -- try not to use in an application where 'stainless abrades stainless' or it'll 'gall' or 'pick up' like you wouldn't believe .. but perhaps this wont be relevant to your application.
They are all a bit guilty of pitting corrosion susceptibility, if exposed to a saliferous environment, for any length of time. Something else to be aware of !.

8)


(Edit ) .. just had a 'dig through' my work links etc...
this is a good site for S/S Info .. haven't referred to it for a long time and had forgotten it, but its a good one :wink:
http://www.msm.cam.ac.uk/phase-trans/20 ... nless.html

looks like you'll be in the realms of grades 410 through to 440 ( A, B or C )

That link is a heavy duty read, but its comprehensive. :wink:

HTH a bit

 

[PowerTool]

And here's another link - at work,our tankcontainers are austenitic;primarily 316L/4401/4404 grades (not very magnetic,but much more corrosion-resistant)

Andrew

 

[p111dom]

Perhaps put this stuff under a layer of stainless..

http://www.tinytintroops.co.uk/Bases/Fl ... sheets.htm

I believe it's used to stop toy soldiers being knocked over.

That an interesting product which could give me more options. The engraver origionally said stainless was ok it engrave but subsequently has said that it can be difficult to see. He's suggested chromed brass plate if I can get around the magnetic problem. He also says silver is a high quality option which might be more inkeeping with the high quality nature of the trophy. Both take engraving better than SS. It's probably going to be a fortune but I'll be getting a quote today. The tinytintroops stuff could give me this option. As the base it to be oak, do you think I'll have a problem sticking the magnetic strip directly to it due to the tanning in the oak?