US1268495A - Metal composition. - Google Patents

Description

ran snares manna entice.

HENRY K. SANDELL, OF CHICAGO, ILLINOIS, ASSIGNOR T HERBERT S. MILLS, OF

CHICAGO, ILLINOIS.

METAL comrosrrron.

No Drawing.

' My invention relates to improvements in y metal compositions. More particularly the invention is concerned with a metallic alloy comprising nickel and tungsten and containing a considerable percentage of carbon.

. I find that such a body has. peculiar properties which render it specially desirable for use as a contact point for making and breaking electrical circuits. In order to prepare my new metallic substance the apparatus and procedure fully described in my prior application No.- 119,656, filed September 12, 1916, may conveniently be employed. In brief, the apparatus in question consists of a carbon block having a trough, or hollow, in its upper surface, which serve-s as the crucible for the production of the. alloy. This crucible is heated by internally developed heat generated by the passage through its walls of an electrical current, which is preferably an alternating current.

The metals to be alloyed, i. a, nickel and tungsten, each of which should be in a relatively pure state for the best results, are introduced intonthe crucible and the latter raised to such a temperature as to cause 85 them to fuse. Powdered amdrphous cari bon, or powdered graphitic carbon is then introduced into the fused mass, the mass be- 7 ing preferably stirred with acarbon stirring-rod. I also find it of advantage to 40 interrupt the current through the crucible at intervals. Within avery few minutes the molten mass within the crucible solidi-" fies or sets. The process is now at an end and the current may be turned off, the crucible permitted to cool and the block of metalcomposition removed therefrom. This blocm'f may then be machined, ground or otherwise fabricated to produce contact points, or other structural elements.

Specification of Letters Patent. Application filed. March 23, 1917. Serial No. 156,973.

Although I prefer to stir in finely divided amorphous carbon, or finely divided graphitic carbon, during the heating of the metal within the crucible, this is not essential to the success of the process, since I find that the crucible walls themselves are eaten away during the process, the carbon required for the composition being thus supplied to a large extent by the crucible itself.

I find that by the process above. described, I am able to produce a metal com- Patented June 4, 1918.

position which is substantially homogenous throughout its mass and which upon analysis shows a percentage of carbon (by weight) of from 2% to 7 per cent. Forthe manufacture of contact points I prefer to use for my metal composition substantially pure nickel and tungsten in about theproportions of 4 parts of nickel to one part of tungsten. The metal composition having these constituents I find to be superior to the composition described in myprior application above referred to, in that it is considerably harder and has a longer life when used as a contact point and subjected to the arcing and sparking which is there met with.

My new metal .composition herein described possesses the peculiarities and advantages of the composition described in my prior application above referred to, and in addition is superior to the last-named com position in the respects pointed out.

What I claim as new, and desire to secure I by Letters Patent, is:

1. A metal composition comprising substantially an alloy of more than 50 per cent. of nickel and less than 50 per cent. of tungsten carrying upward of 3 per cent. of uncombined carbon.

2. A contact point for making and breaking electrical circuits and comprising substantially an alloy of more than 50 per cent.

of nickel and less than 50 per cent. of

.uncombined carbon:

' 3. A metal composltion comprising substantally an alloy of'four parts of nickel :tungsten carrying upward of- 3 per cent. of

4. A contact point for making and breaking electrical circuits and comprising substantially an alloy of four parts of nickel and one part of tungsten carrying upward 5 of 3 per cent. of uncombined-carbom 5. A cast metal contact point for-making and breaking electrical circuits and comprising upward of 7 0 per cent. of nickel, upward of 20 per cent. of tungsten, and upward of 3 per cent. of graphitic carbon. 10 6. A cast metal composition comprising substantially an alloy of-upward of 50 per cent. of nickel and less than 50 per cent. of tungsten carrying upward of 3 per cent. of graphitic carbon. J HENRY K; SANDELL.