US2792301A

US2792301A - Process of manufacturing flint or like pyrophoric material in extrusion presses

Info

Publication number: US2792301A
Application number: US332989A
Authority: US
Inventors: Bungardt Walter
Original assignee: TH Goldschmidt AG
Current assignee: Evonik Operations GmbH
Priority date: 1952-01-25
Filing date: 1953-01-23
Publication date: 1957-05-14
Anticipated expiration: 1974-05-14
Also published as: FR1157714A; GB739174A

Description

United States P ent PROCESS OF MAN FACTURINGLFLINT QR LIKE I PYROPHORIC MATERIAL IN EXTRUSION PRESSES Walter Bungardt, Essen, Germany, assignor to Th. Goldschmidt A.-G. Chemische Fabriken, Essen, Germany, a German corporation No Drawing. Application January 23!, 1953, Serial No. 332,989

This invention relates to. the manufacture offiint or like pyrophoric material, in particular-gin rod formation as disclosed in my copendingapplication Ser. No. 117,069, filed September 21, 1949, and now U. SL'Patent No. 2,660,301.

Experiments have shown that if cerium-iron-alloys melted at a temperature between 1000 and 1200 C. are cast in molds of cast iron which are preheated to a temperature of approximately 600 to 700 C., the thus obtained cast ingots may be used as starting material for the manufacture of hints or like pyrophoric material in extrusion presses. As a source of cerium there may be employed misch metal which contains/the metals of the rare. earth group as main constituents: and has. a. cerium content ofabout 45-55%.

Such material can then be subjectedto the; action of anv extrusion press at temperatures ranging between 400 to 500 C. in order to obtain flint and like rods which are subsequently cut to conventional. lengths, asrequired by the trade.

Depending upon the iron content of such alloys and depending upon the quality of the misch metal to be employed', shaping. through extrusion presses necessitates quite different maximum press powers. If the iron content: increasessuch. press. power must generally be considerably increased. In view of the different degrees of impurities which may be present in the misch metal compounds to be worked upon- (said degrees depending upon the chemical composition of theore employed), this press power may be considerably varied or influenced. The press power becomes higher the greater the degree of impurity which is present in the misch metal.

Extensive experiments have shown that it is possible to add or to admix to the misch metal-iron alloys such types of metals which have the same or a greater heat of formation when combined with oxygen (unit: gram-atom oxygen, than that of the cerium, so that the maximum press power required for the extrusion process may be considerably reduced.

This improving effect of the aforesaid metal additions is generally based on two conditions. In order to reduce the press power during extrusion formation under otherwise substantially equal outer pressure conditions, it appears necessary to reduce the inner friction of the particles within the ingot to be extruded. This can be achieved by eliminating from the ingot disturbing impurities, such as oxides or, possibly, nitrites, hydrides, carbides and similar impurities which are either contained in the misch metal itself or are admixed thereto by otherwise usual additions, such as for instance, iron. In the presence of certain definite metallic element additions and through substantially pure alloy effect a further reduction of the inner friction of the metal particles may be obtained, whereby the extrusion press power will be decreased.

In accordance with the present invention the pyrophoric misch metal-iromalloys with an iron content of 4.5% to 401% are alloyed, in order to reduce the press power needed for carrying out the extrusion, with such metallic elements and in quantities of 0.3% to. 10%, preferably 0.3% to 1%, said elements when compared with cerium having a substantially equal or larger heat of formation during transition into oxides. This effect has been found to be particularly noticeable in the case of titanium, the use of which brings about the desired decrease in the press power required to extnide the alloy even when the same has a quantity of tin, for example, incorporated therein. As is disclosed in the abovementioned U. S. Patent No. 2,660,301, tin or another metal such as zinc, cadmium or magnesium, is usually employed as a hardness-increasing agent for the alloy and thus for the resulting flint so as to reduce wear and tear of the flint during use to a minimum. In addition, other metals'may be employed, for the purpose of reducing the required press power, such as aluminum, magnesium, calcium, zirconium and beryllium, either singly or combined one with the other.

The following examples are given for the purpose of demonstrating the invention:

Example I Misch metalobtained through bastnasite is alloyed with about 20.2% iron, 0.5% magnesium and 1% tin, the content of misch metal being approximately 78.4%. The hardness. of this misch metal alloy in cast form amounts to 89 kg./mm. For the formation through extrusion at: a. temperature of 480- C. a max. press power of 23.0 tons is required. 7

If to the amount of 78.4% of the same misch metal 19.5% iron, 0.5% magnesium, 1% tin, about 0.21% aluminum and about 0.60% titanium are added, then the hardness of the cast alloy is increased to 97.8 kg./mm. the max. press power forthe formation of the alloy in the. extrusion press, however, is reduced by about 46%, now amounting to 12.5 tons.

Example 11 If 78.4% misch metal obtained from mon'azite mineral sand is alloyed with 20% iron, 0.6% magnesium and 1% tin, the hardness of the cast alloy thus obtained amounts to 112 kg./mm. and the required max. pressure for the formation of the alloy in the extrusion press amounts to 33' tons. If 0.6% titanium is added to this alloy, then the hardness of such improved alloy is increased to 116 kg./mm.'- while the max. press power for the formation of the alloy in the extrusion press is decreased by 42%, namely to 19 tons.

Example III If 74.6% misch metal obtained from b'astnasite is alloyed with 23.9% iron, 0.5% magnesium and 1% tin, the hardness of the resultant cast alloy amounts to 98.8 kg/mm. and the max. press power amounts to 25 tons for working the alloy in the extrusion press.

If, however, 74.3% of the same misch metal is alloyed with 23.4% iron, 0.5% magnesium, 1% tin, 0.11% aluminum and 0.66% titanium, the hardness of the resultant alloy is increased to 104 kgjmm. and the max. press power is reduced by 40%, amounting to 15 tons for working the alloy in the extrusion press.

Example I V If a misch metal obtained from bastnasite amounting to 70.6% is alloyed with 28% iron, 0.5% magnesium and 0.9% tin, the hardness of the cast alloy amounts to 108 kg./mm. and the max. press power to 38 tons. If such misch metal amounting to 69.7% is alloyed with 28.1% iron, 0.5% magnesium, 1% tin, 0.12% aluminum and 0.7% titanium, the hardness of the alloy in cast state is increased to kg./mm. the max. press power being reduced for working of the alloy in the extrusion press by about 45%, namely, to 21 tons.

The addition of titanium, as well as of other metals as herein set forth with respect to the misch metal-ironalloy with an iron content from 4.5% to 40% is of extreme practical importance for the manufacture of flint metal rods to be used for various purposes.

By reducing the max. press power in the extrusion press, practical working conditions for this alloy are greatly facilitated, while maintenance and durability of the dies and tools of the press are considerably simplified and improved.

Although specific embodiments of the invention have been described, it should be noted that the invention may be realized in modified form and adaptations of the arrangements herein disclosed may be made, as may readily occur to persons skilled in the art without constituting a departure from the spirit and scope of the invention as defined in the objects and in the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. An alloy capable of being extruded at reduced press powers comprising about 6 to about 95.5 parts by weight of misch metal, about 4.5 to about 40 parts by weight of iron, and about .3 to about 1 part by weight of titanium having, upon conversion to the oxide, a heat of formation per gram atom of oxygen at least equal to that of cerium.

2. In the process of manufacturing pyrophoric flints by extrusion of ingots of an alloy containing a hardnessincreasing agent, about 60 to 95.5 parts by weight of misch metal and about 4.5 to 40 parts by weight of iron, under pressure applied to said ingots at a temperature within the range of about 400 C. to about 500 C.; the step of incorporating in said alloy prior to extrusion of said ingots about 0.3 to about 1 part by weight of a metal having, upon conversion to the oxide thereof, a heat of formation per gram atom of oxygen at least equal to that of cerium, whereby the press power required to extrude said ingots is substantially reduced Without adverse effect on the pyrophoric qualities of said flints made therefrom.

3. In the process of manufacturing pyrophoric flints by extrusion of ingots of an alloy containing a hardnessincreasing agent, about 60 to 95.5 parts by weight of misch metal and about 4.5 to 40 parts by weight of iron, under pressure applied to said ingots at a temperature within the range of about 400 C. to about 500 C.; the step of incorporating in said alloy prior to extrusion of said ingots about 0.3 to about 1 part by weight of titanium and another metal having, upon conversion to the oxide thereof, a heat of formation per gram atom of oxygen at least equal to that of cerium, whereby the press power required to extrude said ingots is substantially reduced without adverse effect on the pyrophoric qualities of said flints made therefrom.

4. The process according to claim 3, being aluminum.

5. The process according to claim 3, being calcium.

6. The process according to claim 3, being beryllium.

7. The process according to claim 3, said other metal being zirconium.

8. The process according to claim 3, being magnesium.

9. In the process of manufacturing pyrophoric flints =by extrusion of ingots of an alloy containing a hardnessincreasing agent, about 78.4 parts by weight of misch metal and about 20 parts by weight of iron, under pressure applied to said ingots at a temperature within the range of about 400 C. to about 500 C.; the step of incorporating in said alloy prior to extrusion of said ingots about 0.3 to about 1 part by weight of titanium, whereby the press power required to extrude said ingots is substantially reduced by about 40 to without adverse eifect on the pyrophoric qualities of said flints made therefrom.

said other metal said other metal said other metal said other metal References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Hackhs Chemical Dictionary, pub. by The Blakiston Co., Philadelphia, Pa., 3rd ed. 1944; page 541.

Claims

1. AN ALLOY CAPABLE OF BEING EXTRUDED AT REDUCED PRESS POWERS COMPRISING ABOUT 60 TO ABOUT 95.5 PARTS BY WEIGHT OF MISCH METAL, ABOUT 4.5 TO ABOUT 40 PARTS BY WEIGHT OF IRON, AND ABOUT .3 TO ABOUT 1 PART BY WEIGHT OF TITANIUM HAVING, UPON CONVERSION TO THE OXIDE, A HEAT OF FORMATION PER GRAM ATOM OF OXYGEN AT LEAST EQUAL TO THAT OF CERIUM.