US1824966A - Alloys and process for improving workability of same - Google Patents

Description

Patented Sept. 29, 1931- UNITED STATES- PATENT OFFICE NORMAN B. FILLING, OI ELIZABETH, NEW JERSEY, ASBIGNOR, BY MEBNE ASSIGN- MENTS, TO THE INTERNATIONAL.NICKEL COMPANY, INC., 01 NEW YORK, N. Y., A

CORPORATION OF DELAWARE -ALLOYS AND PROCESS FOR IMPROVING WORKABILITY OF SAME No Drawing.

This invention relates to an improvement in malleable nickel, alloys contaimng nickel and to other alloys and to an improved process for producing the same, particularly in combining therewith an alkaline-earth metal, either elemental or in alloyed form.

One of the objects of this invention is to improve the ductility, malleability and working properties of such alloys and increase their capacity for being worked by such operations as forging, hot and cold rolling, drawing, pressing or other processes.

It has recently been found that the addition of a relatively small amount of an alkaline-earth metal to alloys containing nickel,

and to other alloys, imparts an enhancement in the properties indicated above without adversely affecting other desirable properties.

Calcium, as well as barium and strontium has been found to be especially beneficial in connection with the production of malleable nickel, iron-nickel alloys and iron-nickelchromium alloys, and will be cited as an illustrative example.

Though various ways of incorporating calcium, barium or strontium with the alloy will be described, it is to be understood that the invention is not limited to theseor any other processes of applying the same. In particular, the invention is directed to the production of malleable nickel alloys, and to other alloys, resulting from combining therewith calcium, barium or strontium, by whatever process employed.

Preferably, the calcium, barium or strontium is added to the nickel or other alloys while they are molten and just before pouring. Two reasons for so acting are that calcium is highly reactive and vaporizes rapidly.

Ithas been found that calcium, barium or strontium is able to replace magnesium or manganese or both in many alloys containing' nickel, thereby avoiding certain undesirable characteristics as will be disclosed more fully hereafter.

With respect to magnesium it is the practice to employ this element as an addition agent in connection with the production of Application filed September 80, 1987. Serial No. 223,238.

malleable nickel and malleable alloys of mckel, such as nickel-copper, nickel-chrom um, etc. Magnesium is, however, partically insoluble in molten iron or chromium, and the presence of relatively small percentages of either of these elements in nickel alloys restrict the solubility of magnesium so much that the'full benefit of its presence is not readily obtained. Calcium, as well as barlum and strontium on the other hand dissolves readily and quietly in iron, in

nickel and in ferrous alloys containingnickel and chromium.

With respect to manganese, it is usually considered necessary by metallurgists to have this element present in alloys containmg nickel in from severaltenths percent to as much as several percent in order to secure a practical degree of malleability in the alloy to permit working by forging, rolling, pressing and the like. However, other properties may often be adversely affected by this content of.manganese, which is tolerated as a concession to the necessary property of malleability. By employing an alkaline-earth metal, such as calcium, bar- 1um or strontium as herein described, it is possible to secure malleable ingots entirely free from manganese, and avoid the undesirable eflects. Even where an alloy contains manganese the forgeability of the same is generally improved by the addition of a small amount of calcium, barium or strontium. 1 y

In general, the amount of calcium, barium or strontium required is between .005% and .5% of the entire melt by weight.

It will be seen, therefore, that calcium, barium or strontium may readily and advantageously displace both magnesium and manganese in malleable nickel or alloys containing nickel, and these not only become invested with the degree of malleability imparted to them by calcium or its equivalents, above noted, but avoid the acquisition of other properties limiting their full scope ofadoption. In addition, calcium, barium or strontium has a property not possessed by magnesium, and that is its ability to lot dissolve in and be alloyed with iron or alloys thereof.

As already indicated, the incorporation of calcium, barium or strontium in the melted alloy may be carried out in many ways, as for instance as follows: The alloying mixture of elements, for instance, nickel and iron is fused in a furnace and refined or treated in any customary manner to secure predetermined properties, excluding or including malleability; then, just before pouring, calcium, barium or strontium or an alloy thereof is introduced into the melt. The reason why an alkaline-earth metal such as calcium is added as the last step' in th e process is because calcium and the other alkaline-earth metals are highly volatile'and reactive and the shorter the period elapsing between its incorporation in the melt and solidification the greater will be the conservation of calcium and/or other alkaline-earth metals used.

Since calcium, barium and strontium and most of its suitable alloys are of lower specific gravity than the melt it is desirable to force the former to the bottom of the melt to aid in securing its complete and uniform solution. This may be done in any convenient manner, such as by attaching the calcium, barium and strontium or its alloy to a rod, or other device which can be quickstrontium,

ly thrust to the bottom of the melt.

It may happen that some calcium, barium and strontium will float to the surface before it is completely absorbed by the melt. In such an instance the calcium, barium and strontium burns to an infusible oxide which may become entangled with the melt in subsequent handling. To avoid this possibility, a thin layer of fused siliceous slag may be provided on the surface of the melt prior to the addition of calcium, barium and or if this is not convenient a little silica sand may be spread over in an amount about equal to the weight of calcium, barium and strontium added. The heat of oxidation of the excess calcium, barium and strontium then suffices to produce a fused calcium, barium and strontium silicate which separates readily from the melt.

The amount of calcium, barium and strontium which is usually satisfactory to comingle with the melt may be between about .005% and .5%, by weight, of the entire melt. An excessive amount of calcium, barium and strontium is to be avoided, since calcium, barium and strontium has a limited solid solubility in iron alloys andin nickel alloys, and if present in undissolved form is apt to occur as a brittle constituent of low fusibility which in itself'impairs malleability.

It was found that in the case of an ironnickel alloy containing 65% nickel and about .7% manganese, the alloy'was rather imperfectly forgeable, tion of .05% to .09% ability was excellent.

but upon the addiof calcium, the forge- However, further additions u to .15% brought about an entire loss of f drgeability. It will be obvious, therefore, that for this alloy and the circumstances of its preparation, the optium calcium addition is between 05% and 09%. Due to imperfect assimilation by the melt, the residual calcium content determinable by chemical analysis is generally less than the amount added. It will be recognized that if the alloy to be treated departs much in composition from the example just cited, the optimum calcium addition may likewise change, and for this reason the invention is not limited to any specific amount of calcium or calcium-alloy addition or content, except as will give the results desired.

The calcium may be used as the elementary metal, or as an alloy with some other metal or metals. Elemental calcium is highly reactive with atmospheric moisture and soon becomes enclosed in a hydrated coating which sometimes interferes with its assimilation in the melt. A calcium alloy may have several advantages over calcium metal, such as increased specific gravity, increased stability against atmospheric attack, and improved fusibility of the alloy or of its oxidized products. Considerable latitude in the nature of such calcium alloys is allowable and the calcium content may range between 5% and 95%. Alloys of calcium with copper, with nickel or with silicon, and containing 30% to calcium, have been found suitable.

As an example to show how calcium improves the workability of nickel alloys, there was first prepared an alloy of 50% iron and 50% Monel metal by fusion with a small amount of ferro-manganese and ferro-silicon yielding, on analysis: manganese 56% and silicon .15%. An ingot of this melt was forged at 1150 C. and began to crack after a few blows of the hammer. Continued forging in an attempt to reduce it to a slab suit'able for rolling was unsuccessful in that these cracks spread, leaving deeply serrated edges. A portion was trimmed free from edge defects and cold rolled, but split apart after a slight reduction in thicknem.

There was then prepared a second melt, similar tothe first except for the addition just before casting of about .1% calcium as a calcium-silicon. alloy, which analyzed manganese 155% and silicon 21%. An ingot of this melt was'then subjected to forging as above to a slab 3 inches wide by of an inch thick, which was then cold rolled Without difliculty to a sheet .050 inch thick.

Entirely malleable alloys may be produced in the complete absence of manganese by means of this calcium treatment. However, it is first highly desirable to deoxidize the melt, which may be done with a little silicon or aluminum.

The advantages of these manganese-free alloys lies in the elimination of undesirable effects which manganese exerts on various physical properties of the alloy, but these are merely incidental improvements in the characteristics of a calcium-treated alloy.

Though there are described herein, as examples, the treatment of an iron-nickel alloy and of an iron-nickel-copper alloy with calcium, barium or strontium, the invention is not limited to the treatment with calcium, barium or strontium of these alloys or any particular types or compositions of alloy. It has been found that calcium, barium or strontium improves also the malleability of many alloys of iron, nickel and chromium (products which are extremely workable and resistant to tarnish, rust and corrosion), and which form the subject of a copending application of Paul D. Merica, Serial No. 223,243, filed September 30, 1927, entitled Tarnish resistant and rust proof alloys, and it appears that calcium, barium or strontium acts similarly with respect to many other alloys of nickel.

The expression alkaline-earth metals as used in the claims excludes the metals magnesium and beryllium.

The invention herein has been described for particular purposes, but it is to be understood that there may be modifications and changes which are to be considered as being claims.

What is claimed is 1. The process of producing alloys containing nickel which includes deoxidizing the principal melt and subsequently adding thereto a metal of the alkaline earth group.

2. The method of producing alloys containing nickel which includes deoxidizing the principal melt and subsequently adding thereto between .005% and .5% of a metal of the alkaline earth grou 3. The method of prorlilcing alloys containing nickel which includes deoxidizing the'principal melt and subsequently adding thereto an alloy containing 5% to 95% of a metal of the alkaline earth group.

4. The process of producing-alloys containing nickel which .includes deoxidizing the principal melt and subsequently adding thereto calcium.

5. The process of producing alloys containing nickel which-includes dexodizing the principal melt and subsequently adding thereto between .005% and .5% of calcium by weight of the entire melt.

6. The method of producing alloys containin nickel which includes deoxidizing the principal meltand subsequently adding within the scope of the following thereto an alloy containing 5% to 95% of calcium.

7. The process of improving the workability of alloys containing nickel which consists in fusing said, alloys, providing at the surface thereof a layer of fused siliceous material, and introducinginto said melt calcium.

8. The process of improving the workability of alloys which consists in fusing said alloys in a suitable furnace, applying to the surface thereof a layer of fused siliceous material, introducing into said melt calcium in an amount about equal to the weight of said siliceous material, and permitting said siliceous material to fuse with excess of calcium.

9. The process of improving the workability of alloys containing nickel which consists in fusing said alloys, providing at the surface thereof a layer of unfused siliceous material and introducing into said melt calcium. I

10. The process of improving the workability of alloys containing mckel WlJlCh consists in fusing said alloys and introducing into the melt a calcium alloy, the oxidized products of which are fusible.

In testimony whereof I have hereunto set In hand. I

y NORMAN B. FILLING.