US1856293A - Process of melting and deoxidizing metals and alloys - Google Patents

Description

Patented May 3, 1932 PATENT ounce 'WILHELM'. REITMEISTER, OF KIRCHMOSER (HAVEL) wERKyGEnMANY PROCESS OI IELTING AND DEOXIDIZING META I-SAND ALLOYS 1N0 brewing. Application filed Kay 10, 1929, Serial No. 362,142, and in Germany June 16, 1928.

lln order to cast metals, for example copper alloys, gunmetal or the like, a melting process is commonly used, in which old metal and new metal are melted together in oil or like ti ltnrnaces without crucibles. It has long been lrnown that during this process copper alloys especially take up oxygen thus forming oxides of the metals which dissolve in the molten bath. These oxides are, however, allll ready present in higher or lower percentages in the ingredient materials. struction of these harmful oxide-compounds has been attempted by means of phosphorus, manganese alloys, aluminium and a whole l series cit other metallic deoxidizing agents. These, however, are only partially effective.

lrnown that carbon has the greatest deoxidicing action on molten iron and steel containing oxygen. The present invention is based on these facts and consists in a process :lor melting and deoxidizing metals and metal alloys, in particular copper alloys, and including iron and iron alloys, in which oxy- M gen compounds and carbon are added to the melting ath, in such proportions that the oirygen content of the oxygen compounds hears exactly or substantially the correct ratio to the carbon-to produce carbon monoxide This is effected by mixing first of all onygen carriers such as UuO or Zn() or MnO or ll eU "with coal-dust in such proportion that the oxygen content of the oxide carrier relative to the carbon content is in proportion to the combining weights for the format-ion of llll A certain excess of coal is necessary according to the metallic oxide andthe alloy employed owing to the unavoidable losses arising when introducing the mixture into the molten metal bath. It has nevertheless been proved that no carbonization talzes place in connection with iron alloys.

The lollowing reactions take place for example:

Ox de dissolved n lll'ature of melting Solid deox1- alloy bath dizmg agent Result hopper alloy CuO C110 C) =2Cu C0 11 0 C110 C) =3Cu C0, llron alloy FeO FeO C) =2Fe CO,

W The principle of the process is to remove Hitherto the dethe oxygen of the bath in the form of CO gas which is insoluble in most melting baths.

The addition of the mixture of oxides and coal-dust to the melting bath in such relative proportion as to produce the unsaturated compound CO is an essential feature. In thisway any harmful excess of oxide or of coal is avoided. According to the metals in the bath only such substances are chosen. as oxide carriers of which the reduction products produce no harmful effects when they come into contact with the molten metal. For example CuO should not be used for steel, nor iron oxide for copper, since Cu is harmful to steel andiron to copper.

A part of the detrimental properties espe cially of copper and copper alloys and also of other non-iron metals is due to material with dissolved carbon monoxide. If the deoxidizing agent according to the present invention is added to such material which cannot be determined either by a chemical or metallographic investigation the metal will become worse because more CO gas is formed in the melting bath. By means of amelt to which one of the deoxidizing agents is added it can V be determined after the cooling whether the present metal was oxidiferous or metal with dissolved carbon monoxide.

With the presence of excessive carbon (disand in what manner the same is to be performed, I declare that what I claim is A process for melting and deoxidizing metals and metal alloys selected from a group comprisin iron, copper alloys, and iron alloys, whic process consists in adding oxyen compounds and carbon to the melting ath, in such proportions that the oxygen content of the oxygen compounds bears substantially the correct ratio to the carbon to produce carbon monoxide gas. I In testimony whereof I aflix my signature.

W'ILHELM REITMEISTER.