US1674438A - Process of producing nickel alloys - Google Patents

Description

Patented June 19, 1928.

N OAK VICTOR HYBINETTE, WILMINGTON, DELAWARE.

PROCESS OF PRODUCING NICKEL ALLOYS.

No Drawing.

This invention relates to an improved method ofproducing nickel alloys from which sound castings can be obtained.

Nickel has a decided afiiuity for gases and absorbs them readily when in a molten state; As a result, the castings produced from the .moltennickel are unsound or spongy due to the setting free of the. absorbed gas. oncooling. This affinity for gases is also. noticed in nickel alloys, pa.r

t-icularlye'when thc'nickel is fairly high in amount. It is known that carbon and silicon tend to reduce such an aflinity, but for many purposes both nickel and nickel alloys are more valuable without the addition of these elements. I

I havediscovered that highly' oxidized (i. e. containing appreciable quantities of oxide)'nickel and nickel alloys, such as ill nickel-iron alloys are unable to hold gases in solution, at least not to. such an extent as to be practically noticeable. I have further discovered that if the oxidized molten nickel or alloy is covered and protected witha slag and treated with a deoxidizer other than carbon, the molten nickel or alloy can be deoxidized without the formation of gas so that a sound casting can be produced free from carbon. This method of procedure is particularly advantageous in 'making malleable nickel alloys and ferro-nickel alloys such as chromium-nickel-iron alloys for rolling or for casting.

In producing such alloys, the pure nickel, or the mixture containing nickel or nickel and iron, is melted in a reverberatory furncae under oxidizing conditions so as to produce a'metal containing about .02% of Oxygen. This oxidizing treatment renders the molten metal free. or practically free fromgases so that a sample of the-metal, cast in an open mold, shows no gas and gives a casting which is smooth on the surface and without signs of sponginess in the grain.

If a sample cast in this way rises and the.

grain is full 0t gas bubbles then the oxidizing has been insufficient. degree of oxidizing has been reached, the molten metal should 1y neutral slag of silicates such as the silicates of lime, magnesia and alumina, but with no large proportion of iron,,-nicke1,' etc. in the slag. The slag may be present during the oxidizing operation or it may be added near the end of the operation. The oxidizing operation not only frees the molten .When the proper farm-nickel to which the alloying-metals be covered with a fairy Application filed September 23, 1922. Serial No. 589,997.

metal from gases but it also removes to a greater or less extent such impurities as carbon. silicon, etc. 1

When a test of the molten metal shows that it has been oxidized sufiiciently and is free from gas, a deoxidizer is then introduced under the slag. The deoxidizer should be one which does not itself form gas-. eons products butwhich forms nonrgaseousoxides. I prefer to use metallic aluminum for this purpose. but other -d'eoxidizcrs free or nearly free from carbon may be used, for example. manganese, silicon, magnesium ()l.lnlXtlll(.S of these with aluminumyetc With aluminum the deoxidizing is-carried to as nearly as possiblethe neutral point so that no oxygen remains and 'no aluminum is present. This point can easily be reached. \Vhen the moltenmetal has been deoxidized in this way, I then add the other ingredients of the alloy such asferro-chromium'," etc.

If these added'ingredientstcontaincarbon,

oxygen and the resulting alloys can accord ingly be cast to give sound castings. I

In order-to make-malleable nickel'or malleable alloys of nickel, there is introduced into the alloy, before cast'ing,a small amount of magnesium,e1ther as pure magnesium in the case of alloys containing less than. 40%

of iron, or as an alloy of magnesium in alloys containingimore iron. If the -highest degree of malleability is unnecessary, magnesium may be dispensed with in alloys con.- taining less than.60% ofnickel, provided manganese, chromium, etc. are present.

The present invention is parti'cularlyadvantageous in producing a superior quality.

of malleable nickel free from carbon' inas;

much as any carbon present originally in the nickel is removed by the oxidizing treat:

'ment, and the subsequent: deoxidizing does not introduce carbon into the metaL- The.

invention is also particularly advantageous in producing ferro-alloys such as chromiumn ekeL-iron alloys low 1nv carbon, since the are added is itself free from'carbon and only such carbon is present in thefinalalloy a8 is added with the alloying metals.

Alloys of chronium, nickel and iron can thus be made by formin a ferro-nickel bat-h in the manner above escribed and then addingferro-chromium. to. the. batln. Since the ferro-nickel bath. is 'itse'lt free from carbon, the only carbon I present is that added with the ferro-chromium, and, where the amount of ferro-chromium added is not too great, a high carbon ferro-chromium can be used, without introducing an objectionable amount of carbon into the alloy. For example, in making alloys containing from 10 to 15% of chromium. around to of nickel and the remainder for the most part iron, the chromium can be supplied in the form of the cheap ferro chromium contain ing around 5 to 6% of carbon and the resu ting alloy will contain less than 1% of carbon. Where it is important to have a lower carbon content, this can beregulated by regulatingthe amount of carbon added with the ferrochromium. The freedom from carbon of the ferro-nickel bath to which the ferrochromi'um is added makes it possible to use a less expensive grade of ferrochromium with-a higher carbon content than would be possible if the ferrocastings. or for other such as ishereinbefore nickel were not itself" free from carbon. The alloys thus produced can be used as heat resisting alloys, or for heat reis'ting purposes.

In referring to a nickeLcontaining bath in the appended claims or to a molten bath of the nickel or nickel alloys. I mean a bath described of metallic nickel, a nickel-iron alloy bath, etc., which are to be used for making castings or which are to be treated with analloying metal .for the manufacture of nickel-containing alloys suitable for casting. v v

I claim:

1. Themethod of producing nickel alloys which comprises subjecting a nickel-containing bath to, an oxidizing treatment, deoxidizing the oxidized bath with a deoxidizer forming a non-gaseous oxide, and adding an gllohying metal or metals to the deoxidized 2. The process of treating nickel or nickel alloys which'comprises subjecting a molten bath of the same to an oxidizing treatment,

and deoxidizing the oxidized bath with aoxidized bath by a slag nearly neutral in character and adding a deoxidizer which forms a. non-gaseous oxide to the bath while protected by the slag. v

5. The process accordi'ng to the preceding claim in which an alloy metal or metals is or are added .to the deoxidized molten bath.

6. The method of producing chromiumnickel-iron alloys which comprises subjecting a molten bath of nickel or nickel an iron to an oxidizing treatment, a deoxidizing the oxidized bath with a deoxidizer forming a non gaseous oxide, and adding ferrochromium'to the deoxidiz'ed bath.

In testimony whereof I afiix my signature.

NQAK vIoToR HYBINETTE.

Images