US2026468A - Weldrod - Google Patents

Description

Patented Dec. 31, 1935 UNITED STATES WELDROD John Howe Hall, High Bridge, N. J., assignor to Taylor-Wharton Iron & Steel Company, High Bridge, N. J a corporation of New Jersey NoDrawing. Application December 31, 1934, Serial No. 760,053

6 Claims. (01. 219-8) 10 lugs and forgings, as, for example, in the building up or restoring, by weld deposit metal, of the badly worn, surfaces of special trackwork, such as manganese steel frogs and crossings, switches, andthe like, and in repairing, by weld deposit,- metal, the broken or otherwise damaged areas of similar or other manganese steel castings and forgings. I Manganese steel is dependent for its charac- .teristics of tough hardness combined with ductiliw upon proper heat treatment and for that reason is extremely diflicult' properly to weld. In an average weld, even when the deposited metal is of proper composition and properly toughened during the progress of the welding, the transition area orpartially fused zone be tween the deposited metal and the unaffected parent metal is made weak and brittle by the heating and partial fusion to which it is subjected. This embrittlement and loss of strength '30 is due to the liberation of carbides in and between the austenite crystals of the metal, and the strength and toughness of the steel so affected can be only partially restored by heat-treatment. After extended experimentation and study I have concluded that the liberation of carbides with its resultant brittleness and weakness is due to the relatively high carbon content of the parent metal, viz. 1.10 to 1.40%. Hence, in one aspect the invention consists in obviating or 40 materially reducing the liberation of carbides by diluting the carbon of the partially fusedor transition zone. In another aspect the invention consists in impregnating the transition zone with nickel to make it susceptible to air toughening and to avoid conditions making for burning.

In short, the objects of'the invention are to provide for first-class weldability regardless of the source of heat for depositing the weld metal; and to insure welds of. high tensile strength and ductility.

In accordance with the inventive thought 'a weldrod is used containing ten to fifteen per cent manganese, one to five per cent nickel, about decimal thirty to about decimal eighty-five per cent carbon, and an efiective amount of silicon;

the preferred composition being an iron or steel alloy containing thirteen per cent manganese, three per cent nickel, decimal seventy-five .per cent carbon and from decimal fifteen to two decimal five per cent silicon. The higher'the 5 silicon content, within the range stated, the better insurance of realizing the ultimate object of soundness of weld notwithstanding that dependence is had on the air toughening properties of the metal of the weld. The relatively high con- 10 tent of. silicon enables the steel to dissolve a high proportion of the gases which cause blow holes. One of the contributory factors to the accomplishment of this result is that the silicon reduces the oxides of iron and manganese presl6 ent, forming SiOz which goes into the slag, so that with less oxide of manganese and of iron present there is lesstendency to the formation of CO gas when the steel solidifies by the reaction between the carbon of the steel and such 20 oxides. The silicon, therefore-is important in that it has both a direct and indirect effect in preventing the formation of blow holes and, hence, makes for'sound steel. A high silicon content is of utility in substantially eliminating the 25 formation of slag and scale, thereby insuring greater fluidityof the weld depositing metal. The ideal range of silicon content is from about one decimal twenty-five to about one decimal sixty per cent. Moreover, the high silicon con- 30 tent, such as indicated, lessens the cost of production of the air toughening steel.

In most cases the desired compositiom in the deposited metal is secured by using a rod of the above analysis. However, I do not restrict my- 35 self to the use of such a rod, as one or more of the constituents-manganese, nickel, carbon, and silicon may be introduced in, the deposited metal by using rods containing someof these constituents, which have been coated with materials 40 containing a high percentage of some of the other constituents in the well-known or conventional manner. 7

Thus, for instance, a rod containing ten to fifteen per cent manganese, decimal thirty to one 45 per cent carbon, and one decimal five per cent silicon may be coated. with a ferro-nickel or metallicnickel in sufiicient amount to give the desired percentage of nickel in the deposited elements, or these elements in the metallic state.

Similarly, part or all of the carbon may be contained in the metals or 'alloys so used as a 55 coating. It is possible also to add the nickel, the manganese, the silicon, orthe carbon to the pool of deposited metal while it is still in the fluid condition. The merit, otthe invention consists in securing a deposited metal of the correct composition, and the scope of this invention is not to be limited to.any onemethod of securing the desired composition in the deposited metal.

The effect of the low percentage of carbon in the deposit metal is, as before stated, to dilute the relatively high carbon content of the partially fused or transition zone of the parent metal and so reduce or prevent the liberation of carbides. The nickel impregnates the transition zone and renders the same susceptible to air toughening. And, if a sufiicient amount of chrome is present in the deposit metal, hardening action under cold working is considerably augmented.

It is a furthercharacteristic of the invention that the rods, pencils 'or wires embodying, the described air toughened manganese steel do not require flux coating. However, the use or a flux coating or covering is a matter of expediency or choice according to the particular shop or field practice and whether thewelding is done with alternating or direct current.

This application is a continuation in part of my application Serial No. 474,069, filed August 8, 1930.

Having described the invention, what is claimed is: v

1. A weld rod for welding austenitic manganese steel articles, said rod consisting of austenitic manganese steel having air toughening properties and characterized by a silicon'content of between abort decimal fiity to about two decimal five per cen 2. A weld rod consisting of austenitic manganese steel having a toughening properties 5 through its inclusion of nickel and characterized by the fact that it has a relatively high content of up to about two per cent silicon for the purpose of reducing oxides of iron and manganese on the fluid weld deposit, thereby minimizing the for- 10 mation of slag and scale and making for great strength and toughness in the weld. v

3. An iron or steel article containingten to fifteen per cent manganese, one to five per cent nickel, decimal thirty up to less than one per cent 15 carbon, and an eflective amount up to two decimal five per cent silicon.

4. an iron or steel article containing ten to fifteen per cent manganese, 'one to five per cent nickel, one to eight per cent chrome, carbon in 20 the fraction of one' per cent,'and silicon in an effective amount up to two-decimal five pencent.

5.\ An iron or steel article containing ten to fifteen per cent manganese, one to five per cent nickel, decimal thirty up to about one per cent as carbon, an effective amount of silicon up to about two decimal five per cent, and suflicient chrome to cause the metal to harden under-cold work.

6. An iron orsteel article containing ten to fifteenper cent manganese, one to five per cent :0 nickel, decimal thirty to about one per cent carbon, and silicon from about one decimal twentyfive to about one decimal sixty per cent.

JOHN HOWE HALL.