Magnetic brass!!?

[02jcole]

Hello,

I recently found a scrap yard with some hard brass bar for sale, about 2" dia so brought a couple of lengths to make the bearings for the back axle of my 4" scale tasker traction engine. While I was there I asked if I could swop brass swarf for brass bar ;D and he said it was all the same to him as long as it was clean with no steel in it. So I cleaned down my lathe of all steel swarf so that I could save it all, after I finished I thougt it would be a good idea to check that no steel swarf got mixed in so I put my large magnet in a platic bag to hopefully attract it but found the brass swarf was also attracted!! I checked the other similar bar and the leftover off cut and it was also magnetic.

The bar was very tough to turn and required coolant to keep it cool, I also noticed that the swarf came off a a stream like steel, not in a shower like other brass I have turned.

What do you think it is.........

Regards James.

[baggo]

Hi James,

One possibility is that it could be aluminium bronze. Abby pointed out in another thread that this is slightly attracted to a magnet. I believe that there are other copper based alloys which can exhibit magnetic properties e.g. those containing nickel or cobalt.

John

[ravensworth2674]

'copper' coinage?

[weldsol]

May 12, 2008 8:01:03 GMT @ravensworth2674 said:

'copper' coinage?

Modern coins are steel base due to the price of Copper being greater than the face value of the coin. (to stop the coins being melted down and sold for scrap)

[JohnP]

One place where I worked we used to make tools which were used in the oil industry to determine the inclination and azimuth of the drilled hole. Inclination is determined by using accelerometers to determine which way was down, and the azimuth (compass direction) is determined using flux gates, which sense the earth's magnetic field. Obviously we had to be careful what materials we used, and brass was one thing we had to avoid. Although it isn't always, it can be magnetic. I always assumed this was down to the small amount of impurities allowed in some brass alloys, but I don't have any proof.

JohnP