are stainless steel props magnetic?

[D.spencer]

I got a dumb newbie question. Are stainless steel props magnetic? mine is and it is certainly not aluminum. But, my research so far says nothing about steel props. (1977 johnson 140 hp). I don't know if it is the original one. thing is, it doesn't look like stainless steel props typically look. I actually thought it was aluminum until I stuck a magnet on it.

 

[Uraijit]

Re: are stainless steel props magnetic?

Stainless steel is not always necessarily magnetic. If there's nickle in it, it will not be magnetic.

However, if your prop is magnetic, then clearly it's NOT aluminum, and therefore must be steel. If it ain't rusting after all this time, it's gotta be stainless. I'll bet you if you hit it up with a wire wheel or a buffing pad, it would be shiny again...

 

[Frank Acampora]

Re: are stainless steel props magnetic?

Lower grade stainless has a portion of steel alloyed in it and would therefore be magnetic. It would be a bit less corrosion resistant. Higher grades and food grade stainless (304, 316 ) are primarily nickel and chromium. These alloys are non-magnetic, highly corrosion resistant, but lower in tensile strength.

The prop maker may have traded off a bit of corrosion resistance for higher strength on your prop.

 

[stubblejumper]

Re: are stainless steel props magnetic?

Stainless steel alloys such as 416 are magnetic.They are not as corrosion resistant as the 3 series,but they are stronger.They are very common in the firearms industry because of that strength.

 

[Tacklewasher]

Re: are stainless steel props magnetic?

If I were to search here, I would find a post about my old SS prop that does not look stainless. Basically, and old OMC stainless that looks like an aluminum, except it is a bit rusty on the edges.

I suspect you have something similar.

 

[ivar]

Re: are stainless steel props magnetic?

I read somewhere that "15-5" was a common steel alloy to use for props, ie 15% chrome, 5% nickel. And if I remember correctly, not magnetic.
Anyone..?

 

[DutchMerc]

Re: are stainless steel props magnetic?

If it is a welded prop, it is verry unlikely that it is the non-magnetic 316 or 303/304. This material will herden to much if welded, and there will be to much tension in the prop after cooling. More likely they used the lower grade stainles 430F ore simular; this is verry easy to weld, easy to deform if forged, and still "stainless". However in salt water it might start to oxidate, but only so much that it will loose its shine. This material is magnetic....

 

[D.spencer]

Re: are stainless steel props magnetic?

I took the prop to the shop here in town today (for repairs) and asked them. It is an OE Johnson prop which was originally teflon coated. All the coating had worn off and it was starting to rust some. I know that there are magnetic grades of stainless steel -I just thought that,for the most part,*all* S/S props were of the shiny ,non rusting types .