US2967767A

US2967767A - Iron powder composition for gas-cutting, gas-washing, and gas-scarfing

Info

Publication number: US2967767A
Application number: US776707A
Authority: US
Inventors: Nishikiori Seiji; Okada Yasuharu
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-12-07
Filing date: 1958-11-28
Publication date: 1961-01-10
Anticipated expiration: 1978-01-10

Description

IRON POWDER COMPOSITION FOR GAS-CUT- TING, GAS-WASHING, AND GAS-SCARFING Seiji Nishikiori, 40 Jiodani, Hinaga, Chita-cho, Chita-gun,

Aichi-ken, Japan, and Yasuharu Okada, 18, 1 Yomeicho, Mizuho-ku, Nagoya-shi, Japan No Drawing. Filed Nov. 28, 1958, Ser. No. 776,707

Claims priority, application Japan Dec. 7, 1957 1 Claim. (Cl. 75--.5)

This invention relates to iron powder and more particularly to the iron powder which is used for the purpose of gas-cutting, gas-washing, and gas-scarfing, which will hereinafter be called simply gas-cutting.

It has heretofore been conventional to employ pulvertized electric iron or reduced iron powder as metal powder used for gas-cutting purpose.

Although these types of iron powder may well serve the purpose of the gas-cutting of alloy steels such as stainless steel, they can not be applied to the gas-cutting of cast iron, super heat-resisting alloys, and non-metallic substances like concrete and refractory brick on the ground that the heat evolved by the oxidation of the iron powder is insufiicient to supply the requirements for the gas-cutting of such types of material.

Accordingly, attempts have been made to enhance the oxidation heat required for the gas-cutting of such types of material by adding a suitable amount of aluminum powder to the iron powder which is usually employed alone with the gas-cutting. However, uniform mixing of aluminum powder with iron powder is hardly achieved because of a considerable difference in their specific gravities, and thus in practice the ratio of these two types of metal powder in the mixture when used varies at all times. Moreover, aluminum powder in a pulverized state is very susceptible of combustion when exposed to a heating gas flame and is found as aluminum oxide when brought in contact with the oxyacetylene cutting flame. Consequently the heat given to the cutting surface of the objective is found scant. Thus, the operation of the gas-cutting employing conventional metal powder has been carried out with great difficulty at low efliciency resulting in deleterious defects on the surface cut of the objective. In addition, aluminum powder is costly.

The present invention provides a unique iron powder for gas-cutting use to remove the aforesaid disadvantages incurred in gas-cutting practice which employs the existing metal powder.

In the preparation of the iron powder according to the present invention, an addition of at least one element selected from the group consisting of aluminum, magnesium, silicon, calcium, titanium, and zirconium each of which is very susceptible of combustion emitting enormous heat of oxidation is so made to the mother metal which may be iron or copper as to constitute a fragile alloy having a specific gravity which is not far from a commercial iron powder and then said alloy subjected to pulverization is blended with said iron powder. Due to its fragility said alloy is prone to an easy and inexpensive pulverization. The uniform mixture comprising said alloy powder and a commercial iron powder is less susceptible of oxidation as compared with aluminum powder so that the oxidation heat is given direct to the cutting surface of the objective resulting in increased efliciency of the gas'cutting operation. The unique iron powder employed for the gas-cutting pur- I pose according to the invention is prepared by so making an addition to a base metal which may be iron or copper 2,967,767 Patented Jan. 10, 1961 ice of at least one element selected from the group consisting of aluminum, magnesium, silicon, calcium, titanium, and zirconium as to produce a fragile alloy which is then thoroughly mixed with a commercial iron powder. The total quantity of the alloying elements appropriate for the addition to the base metal ranges in Weight from 10% to 60% of the base metal within which range the alloy produced is subject to pulverization at low costs.

In addition, thorough mixing of said alloy with the commercial iron powder is made feasible because of the similarity in the specific gravities and thus in practice the amount ,of said alloy is optionally determined in relation to the specific objective which is to be subjected to gas-cutting.

However, in case the addition of said alloy to the base metal exceeds 60%, the difference in the specific gravities of said alloy between the commercial iron powder increases and the pulverization capacity of said alloy decreases so that difficulties will be encountered in obtaining a uniform mixture of these two constituents. On the other hand, if the addition is short of 10%, the resulting alloy will become ductile losing the properties of fragility and disintegration, so that the uniform mixture will be diflicult to obtain without a sacrifice in increasingly expensive pulverization of said alloy, and thus the advantages expected by the addition of the alloying element are offset.

The alloy powder contained in the iron powder according to the invention is not subject to instant combustion when exposed to oxidizing flame but is susceptible of rapid combustion only when brought into contact with the oxyacetylene flame in the cutting region so that a large amount of the heat evolved can be given to the cutting surface of the objective. In addition, since the product of said combustion comprises iron oxide accompanying at least one type of oxide from the group consisting of A1 0 CaO, SiO TiO Zr O and MgO, the molten slag thus produced as a result of the combustion is lower in melting point and higher in fluidity than the slag comprising practically only iron oxide which is produced from the conventional iron powder. Consequently, clean cut cutting surfaces are acquired with higher efficiency in the gas-cutting with the iron powder prepared in accordance with the present invention.

Some preferred embodiments of the invention will be described in detail wherein the examples given are for the purpose of illustrating preferred embodiments only and not for the purpose of limiting the same.

Example A.-Ir0n powder containing ferrous alloy (1) A soft steel is heated to melt at an elevated temperature for making an alloy containing 45% aluminum. The alloy of this type is so fragile that it gradually breaks up itself and accordingly the pulverization of the alloy is easily carried out. Owing to the specific gravity of 5.6 which approximates that of commercial iron powder, said alloy can be uniformly mixed with commercial iron powder. With iron powder in accordance with the invention comprising 30 parts of said alloy and 70 parts of commercial iron powder, clean cut gas-cutting is successfully carried out at highest efliciency with respect to cast iron, stainless steel, copper, and nickel-alloy, etc. In fact, the iron powder in accordance with the invention enables the speed of cutting a 30 mm. steel plate to increase to 200 mm./min. from mm./min. with the conventional iron powder.

(2) An alloy of iron-aluminum system containing 40% aluminum and 5% calcium or silicon is easily crushed. An iron powder in accordance with the invention comprising 50 parts of such alloy and 50 parts of commercial iron powder enables non-ferrous metals such as nickel, Monel metal, brass, and hastalloy to be easily cut.

(3) An iron powder in accordance with the invention comprising 30 parts of an alloy, which has been prepared by an addition of 40% aluminum and %titanium to a ferrousbase metal, and 70 parts of commercial iron powder renders the suflicient clamping of copper or steel plate needless for the successful lap gas-cutting of copper and stainless steel.

(4) In gas-cutting employing a conventional iron powder of 100 mm. cast iron plate, the consumption of the iron powder was 5 kg. per meter of the cast iron plate cut at the cutting speed of 97.5 mm./min. With the unique iron powder according to the invention comprising 90 parts of commercial iron powder and parts of an alloy consisting of 55% commercial iron and 45% aluminum, the consumption of the new iron powder proved 3.5 kg. per meter of the cast iron plate cut at the cutting speed of 139.6 mm./min., thus showing approximately percent saving in the iron powder consumption and 20 percent increase in the operation efliciency.

Example B.Ir0n powder containing cupreous alloy An alloy consisting of 55% copper and 45 aluminum is very fragile and subject to easy pulverizing. The iron powder comprising 90 parts of commercial iron powder and 10 parts of said alloy in accordance with the invention makes with ease the gas-cutting of such materials as stainless steel, cupreous-alloys, aluminum-cast iron, and

refractory bricks possible. With this new iron powder the Example C.-Gas-washing In employing the conventional iron powder for gaswashing 5 mm. in depth of the surface of a steel plate having 280 mm. length and 180 mm. width, it required 7 min. with the consumption of 1.4 kg. of the iron powder. In the case of the new iron powder in accordance with the invention comprising 90 parts of commercial iron powder, 5 parts of an alloy consisting of 55% iron and 45 aluminum, and 5 parts of an alloy consisting of 65% iron and titanium, the consumption of the new iron powder was 0.85 kg. requiring 5 /2 min, for carrying out the same work. Accordingly, the saving in the iron powder consumption was about with a 20% increase in operating efficiency.

We claim:

An iron powder composition used for gas-cutting, gaswashing or gas scarfing purposes comprising a mixture of 1090% by weight of commercial iron powder and 10- 90% by weight of a powdered alloy comprising a copper base metal and at least one alloying element taken from a group consisting of aluminum, magnesium, silicon, calcium, titanium, and zirconium within the limit ranging from 10% to by weight of said base metal.

References Cited in the file of this patent UNITED STATES PATENTS 2,916,373 Freeman Dec. 8, 1959 FOREIGN PATENTS 160,479 Australia Jan. 10, 1955