Telling Stainless Steel from Other Metals 2

[Damineh]

My supervisor had taught me that I can check whether a piece of metal is stainless steel or not using a magnet. That’s all!
2 days ago, we had a rusted bearing and when he checked each and every component of the bearing with a magnet, he assured everyone none of the parts were stainless steel as the magnet attracted all of them.
We put all the components of a new bearing in water to see whether it would rust. It hasn’t yet. So we are clear that the bearing had been stainless steel and that the magnet test is not the correct way of stainless steel testing.
Now… I found out that magnet ofcourse attracts all magnetic materials such as nickel and monel and …. And that stainless steel at different grades has some percentage of Nickel.
Now… is there any other way to test for stainless steel?? How would I know what grade it is?? I don’t rely on the company that’s supplying us with the steel.

 

[Maui]

How hot is the fire? Most of the tool steels and high speed steels that we manufacture have a solidus temperature slightly above 2200 F. If the fire is well below this temperature then no, it will not melt. But a variety of other changes can take place within the steel depending upon what temperature it is heated to and the length of time it is held at that temperature.


Maui

 

[deepdrawncomponent]

Our company makes millions of stainless steel components out of AISI 304 and other stainless steels. Before putting the material into the press the metal is non magnetic, but after the components are produced they are very magnetic. Seeing as we make components also for electrovalves one of the requestes where that the component should not be magnetic,and it was also asked to be made in AISI 304 (for obvious financial reasons). We had to propose this deep drawn piece in AISI 305 which is NEARLY totally non magnetic. This solution satisfied our customer.
In other words work hardening (from deep drawing for example) makes the components magnetic, so the only thing you can do about it is make them in AISI 305 and then if the component is still too magnetic send the component to a laboratory for a chemical composition check the results with the AISI standard which you can get from any stainless steel supplier
I hope this can be useful for you
best regards
Marco

 

[Damineh]

We were barbecuing on our camping trip last Saturday and our stainless steel meet holders (cooking tool) were left in the fire. My friend asked us to take it out because it would melt. I started arguing that it wouldn¡¦t, as the melting point of stainless steel is much higher than the temperature of wood fire. This argument went on for two days! That night, I left an aluminium (melting point of 660 ¢XC for non-alloys) rod in the fire and it DID melt and even broke in pieces! The next day, I looked for temperature facts to prove I was right. This is all I needed to prove:

The melting temperature of stainless steel is 1371-1454„a C (2499.8 to 2649.2„a F). Wood logs typically burn at a temperature of 204.44 to 232.22„a C (400 to 450„a F), depending on the dryness of the logs, resin content, or contaminants. ¡§ Stainless steel with melting point of 1371-1454„a C would not melt when placed in wood fire of 204.44 to 232.22„a C.¡¨ If I want to go deeper, I can say that the temperature of stainless steel rod will come to equilibrium with the ambient temperature and the fire considering conduction and convection, and even radiation. That would be too much for an electrical engineer to know. But I think I proved my point with the quoted sentence, eh?! Or am I wrong?


Thank you.

Damineh

 

[Metalguy]

Yes, it would be difficult to melt aust. SS in a wood fire, but the temps. you quote are the *ignition* temps. of wood, not the temp. of the flames!

Just guessing, I think the flame temps. are ~1,500+ deg. F.

 

[jbmathieu]

stainless steel 300 series are not ferromagnetic
Stainless steel 400 series are ferromagnetic (I measured a saturation magnetization around 1.14T for 440C stainless)

as for the others series, i do not know but I a sure that opposedly to common knowledge, stainless steels can be ferromagnetic.