US1947167A - Alloys - Google Patents

Description

Patented Feb. 13, 1934 PATENT OFFICE ALLOYS Burt Howell Payne, WestfieltL-N. J., assignor to Stulz-Sickles Company, Newark, N. J.

No Drawing. Application August 23, 1932 Serial No. 630,055

2 Claims. (01. 75-1) My invention relates to novel alloys and novel methods for producing the same, and more particularly relates to a novel silicon manganese nickel alloy.

In my patent granted September 13, 1932, of which this application is a continuation in part, I have limited the claims to my novel welding rod, although that application describes the novel manganese nickel alloy which is the invention in this application.

As described in my parent application, manganese nickel alloys have heretofore been produced having the properties of toughness, resistance to impact, and abrasion. Such manganese nickel alloys usually consist of carbon, manganese, nickel and silicon. The manganese and nickel present provide the desired toughness to the alloy; the nickel, in addition, if added in proper amounts, makes the alloy self-air toughening. Of these constituents, the most expensive is the nickel and a reduction of the amount used is therefore highly desirable.

I have discovered that a definite relationship exists between the percentages of nickel, manganese, and carbon present for the production of a manganese nickel steel having the properties of air toughening and resistance to abrasion, and more specifically that the carbon content may be brought as low as .60%, bringing the nickel content proportionately down to-2.50%.

The percentage of carbon present must be closely controlled since with a carbon content below .60%, the alloy would not have the necessary toughness and peen hardness and, accordingly. this is the lower limit for carbon.

On the other hand, I have discovered that it is not necessary to go above .85% to produce these desirable properties, particularly if a proper relationship is maintained between the carbon content and the nickel. In fact, the carbon content must be kept low and between these limits because if the carbon content is increased much above these limits, the resulting alloy is difficult to roll. Furthermore, difficulties in producing an air toughening alloy increase where the carbon content is permitted to go above the limits specified herein without the addition of considerable nickel.

It is necessary that there be at least 11% of manganese present in my manganese nickel alloy and preferably this percentage should be somewhat higher, ranging from 11 to 13.5%, particularly where the alloy is to be used as a welding rod or as a parent metal in a welding operation. The somewhat higher percentage insures against any loss of manganese during welding and produces a weld having at least 10% of manganese present.

The percentage of nickel present is extremely important since this is the most costly element 69 in the alloy. The addition of proper percentage of nickel makes the manganese steel, air tough ening. At the same time, no more nickel should be added than is absolutely necessary in view of the excessive cost of this element. 55

Nickel also reduces the brittleness of the steel and retards crystallization with only a slight sacrifice of high degree work hardness and wear resistance.

As already explained, by maintaining the car- 70 bon content low within the range of from .60% to 35%, the nickel content may be correspondingly maintained within the range of from 2.50% to 3.50%.

However, the nickel may not go below 2.50% and still retain the air toughening property and, accordingly, this is the lower limit of the nickel which must be present if the alloy is to retain the above described properties. So long as a definite relationship between the nickel and carbon hereinbefore described is maintained, the alloy even with this low percentage of nickel, will be air toughening and still have peen hardness.

Because of the air toughening property of my alloy, I have found that it is a very desirable 5 parent metal in a welding operation. The recent increase in the practice of welding and building up 14% manganese steel castings, etc., with my nickel silicon manganese Welding rods, provides considerable utility for my alloy as a parent metal in welding. In order that the alloy, after being welded, retain its original properties, the manganese must be protected from oxidizing in the air during welding.

This I accomplish by adding to my alloy, silicon in excess of .60%. The silicon, however, if present in too large a quantity, is an impurity and accordingly the content must not exceed .90%. By providing a silicon content between .60% and .90%, during welding, the oxygen in the air will first attack the silicon, forming a silicon oxide, and leave the manganese unaffected so that substantially little or none of the manganese is oxidized. This condition is obtained only if the silicon content is above 50%, as any silicon content below that is insufficient to prevent a considerable loss of manganese through oxidation and therefore a material change in the property of the alloy as a result of a welding operation.

On the other hand, if the silicon content is permitted to exceed .90%, the excess silicon comprises an impurity and an undesirable slag when used as a welding rod. In other words, suflicient silicon must be present to take up all of the oxygen during the period while the welding operation is being carried out so that little or none of the oxygen will be available for oxidizing the manganese, but no more silicon must be present than is enough to do exactly this.

My preferred alloy may be manufactured in any desired manner, although I prefer either of the following processes:

In the first process, the electric arc furnace process, 11 to 14% manganese steel scrap is used. To this is added the necessary low carbon ferromanganese to give the proper percentages of carbon and manganese, and to this there is added the proper percentages of nickel and silicon.

In the second process, a high frequency induction furnace process, to iron scrap there is added the proper amount of ferro-manganese, nickel and silicon.

Alloys in accordance with my novel analysis may be used as a parent metal in track work, gyratory crushers, plate crushers, centrifugal pump-shells, liners, side plates, impellers, or any part usually made of 11 to 14% manganese steel, and is preferable to ordinary 11 to 14% manganese, as it can be welded and built up with welding rod of the same composition without damage to the parent metal, and can be surfaced with any of the hard-surfacing welding rods by either gas or are process.

In the preferred analysis above described, even where the oxyacetylene welding process is used. there is no danger of destroying the properties of the original casting by the heat during weld ing, since this alloy does not require a special toughening heat treatment or heat treatment with a quenching bath.

This analysis has also been found to be freer from pipes, blow-holes and weak metal than ordinarily found in straight 11 to 14% manganese steel and as a result eliminates the tendency of the parent metal to sink. due to impact to which it is ordinarily exposed. For example, a frog made of straight 11 to 14% manganese steel may require building up. This is accomplished by grinding away all the weak metal and replacing it with welding. By making the track work of my alloy, it is only necessary to weld on a uniform layer directly on the wornout parts; that is to say, a re-surfaced rather than a re-built part.

When a straight 11 to 14% manganese steel casting is welded, any overheating of the parent metal removes the treatment in the parent metal and returns the part to its original condition when cast; that is, brittle and without strength. But castings and rolled or forged parts made from my analysis, can be heated and re-heated to any temperature up to 2000 F. and allowed to cool, and still have the characteristics of 11 to 14% manganese steel that has been subjected to the usual heat and quench treatment.

In the production of castings, such as special trackwork and crusher equipment, it is necessary, in order to bring out the toughness in 11 to 14% straight manganese steel, to heat it to 1940 F. and quench immediately in water. When this is done, a certain amount of distortion inevitably results which is corrected in the manufacture by inserting the member in large presses for straightening the distorted casting, which is an expensive practise.

By the use of an air-conditioned casting of my preferred analysis, water quenching is dispensed with. Thus, it will be evident that where a nickel manganese silicon casting is manufactured for a special part subject to heat and also to impact and abrasion, my preferred analysis may be used without affecting its properties due to the heating. When a part is Worn out, a resurfacing may be accomplished by a simple welding operation and the resulting weld will still retain the original toughness and wear resistance of the parent metal.

In accordance with my alloy, large sized pipes for dredging, made of my plate analysis, may be built up of a number of sectors welded to each other. By the use of my analysis, a smoother surface is obtained when welding, which saves considerable grinding on track work. Floors of heat treating furnaces may be made in accordance with my analysis as it is unaffected by the heat of the furnace in operation, up to 2000 F.

My alloy may also be used for plate products and bars that are to be cold crimped or fabricated. The ideal carbon analysis therefor is .75%, which gives the maximum ductility and, at the same time, high tensile strength, and as a result, resistance to abrasion.

This alloy is intended for welding by oxy-acetylene and electric arc processes, for fabricating into woven wire screens, and fabricated sheets for screening and separating abrasives such as coke, trap rock, coal, etc. With this alloy, with iron and diamond dies, wire as small as .003" in diameter has been drawn. This is manufactured into wire cloth of various dimensions and openings. The alloy may also be used for bars, special shapes, plates, sheets and fabricated products such as pedestal liners, guide liners, bins, and also for a core for rolling hollow drill steel and subsequently drawing of core into welding rods, as described in my applications for Letters Patent, Serial Nos. 560,877 and 618,025.

The alloy is practically non-magnetic in the hot-rolled or cast condition, but in cold crimping and drawing it sets up a slight magnetism which may be used. if desired, or if undesired, may be eliminated by a special heat treatment.

It also finds excellent application in wet drawn wire which is subsequently coated with tin for binding of armatures, due to its non-magnetic condition. as it will not hold any permanent magnetism. The alloy is supplied in cold drawn wire or special soft annealed wire by a special heat treatment to a predetermined temperature in a continuous furnace in hydrogen atmosphere, or 3 without it. Since it has about the same coefficient of expansion as alum num. it functions well, when combined with aluminum, in the lining of airplanes, motor cars and bus engines.

Although I have, in the above, given the specific percentages for an ideal analysis, these vary somewhat in accordance with the function of the final product, as follows:

Although I have illustrated specific uses of my alloy, it will be understood that it has other uses coming in the scope of my invention, and I do not intend to limit myself except insofar as set forth in the accompanying claims.

I claim:

1. A manganese nickel steel for parent metal in Welding operations comprising carbon, manganese, nickel and silicon, in which the carbon content present is in excess of .60% and less than .85%; the nickel content present is in excess of 2.50% and less than 3.50%, and is substantially four times the amount of carbon present; the manganese content present is excess of 11% and less than 13.5%; and. the silicon content present is in excess of .6% and less than .95%, and the balance is 2, A manganese nickel steel for parent metal in welding operations comprising carbon, manganese, nickel and silicon, in which the carbon content present is in excess of .60% and less than 35%; the nickel content present is in excess of 2.50%

and less than 3.50% and is substantially four times the amount of carbon present; the manganese content is in excess of 11% and. less than 13.50% and in a ratio of 12 to 1 with respect to the carbon and in a ratio of 4.04 to 1 with respect to the nickel content.

BURT HOWELL PAYNE.