US1028216A - Melting and casting magnesium and alloys thereof. - Google Patents

Description

A a r i I 3 H 1 a. i a

arrtion.

BERTHOLD HOFFMANN AND ROBERT SUGHY, OF GRIESHEIM, GERMANY, ASSIGNORS TO CHEMISCHE FABRIK GRIESHEIlVI -ELEKTRON, 0F FRANKFORT-ON-THE-MAIN, GERMANY, A CORPORATION OF GERMANY.

MEETING AND CASTING MAGNESIUM AND ALLOYS THEREOF.

1,028,216 Specification of Letters Patent.

No Drawing. Application filed June 8, 1910.

To all whom it may concern:

Be it known that we, Bnn'rnono HOFF- MANN and ROBERT SUoI-IY, subjects of the German Emperor, and residents at Griesheim-on-the-Main, Germany, have invented certain new and useful Improvements Tie-- lower oxids and nitrids and finally burning so that the casting becomes soiled to an objectionable degree. f

Processes are already known according to which the aforesaid difficulties are overcome, but the process in accordance with this invention possesses over these, the advan-- tages of great simplicity, cheapness, and reliability. a

' We have discovered that the propensity of molten magnesium and alloys thereof to enter into reaction with the air is mitigated by the addition of a small amount, of calcium so that, at the temperatures in question, magnesium and its alloys can be cast without any oxid and nitrid being formed or any other injurious action taking place. Thus for instance magnesium and its alloys, when mixed with from one tenth to one half of one per cent. of calcium flow, in the air, ina silver-white stream, from the crucible, without the aforesaid dark skin being formed and burning taking place. They fill up the molds in a perfect manner, and they give dense clean castings which do not eflioresce under the action. of the air. They come out of chilled molds quite clean and leave sand,or loam, molds, without an objectionable skin. This remarkable action of calcium, can be obtained with an addition of even less calcium than that above stated. Magnesium, or magnesium alloys, treated, as aforesaid, with calcium, can beheated Patented June 4L, 1912. Serial No. 565,864.

much above melting point without entering into reaction with the air and this property is not lost after repeated remelting. Besides this the presence of calcium has the further advantage, that it forms with the hydrogen, mostly contained in magnesium and its alloys, a hydrid which covers the surface of the fused metal, or alloy, thus greatly facilitating the production of dense castings free from hydrogen bubbles. It is not necessary to use the calcium, in the metallic form, as it can be introduced in the form of an .oxid, or other compound, capable of being reduced by magnesium. Lime which is cheap and generally obtainable can be used; Clemens Winkler (see Berliner Bem'chte 23, 122) having already shown that it can, like other oxids, be reduced by magnesium. The calcium can be furnished in any other suitable manner to the metal, for instance by the addition of a calcium compound during the electrolytic to be produced, the calcium may be used alloyed with one of the components of the alloy.

The following examples will illustrate how this invention can be carried out in practice, but it is not limited thereto:

- Example 1:, Into a suitable crucible 10 kilograms of magnesium and 50 grams of calcium, are'introduced and the crucible is covered with a lid and heated to 700 centigrade. After energetic stirring, the melt is ready for casting. I

Example 2: 10 kilograms of magnesium and 70 grams of powdered burnt lime are introduced into the crucible and the operation is further conducted as in Example 1.

It will be appreciated that the amount of calcium employed is so. small that it cannot impart to. the metal the characteristics of a calcium alloy. In fact the calcium so nearly disappears during the operation that the cast metal contains only a trace thereof, no more pronounced than the traces of other metals commonly existing-in magnesium as innocuous impurities.

We claim The herein described process of melting manufacture of magnesium. If. an alloy is v and casting magnesium and alloys thereof names to this specification in the presence of whlch conslsts 1n melting and casting said two subscriblng W1tnesses.

metal in the presence of caleium the amount BERTHOLD HOFF MANN. of calcium employed being so small that it ROBERT SUCHY. cannot impart to the metal the character of \Vitnesses: a calcium alloy, FRANZ HAssLAoHER,

In testimony whereof we have signed our ERWIN DIPPEL.

Copies of this patent may be obtained for five cents each, by addressin he Commissioner of Patents,

Washington, D.