US1954297A - Welding - Google Patents

Description

Patented Apr. 10, 1934 WELDING James M. Keir, Bayside, N. Y., assignor to Oxweld Acetylene Company, Virginia a corporation of West No Drawing. Application March 26, 1931, Serial No. 525,598

3 Claims.

The invention relates to metal deposition or welding, especially by the use of the carbon are or metal arc. It is among the objects of the invention to produce deposits which are composed essentially of carbon steel and are free from deleterious occlusions, to deposit the metal rapidly by using a large current in the arc, and to avoid delays growing out of a need for playing the are on the metal for refining purposes after the weld is formed.

Heretofore, readily oxidizable chemical elements have been applied as coatings or cores to rods for arc welding. The purpose of most rods of this kind was not to deposit a carbon steel. They were used to deposit alloy steels containing the elements used in the coating or core. Whether or not there was an excess 01' coating elements sufficient to produce an alloy, I am not aware of any of these rods which would deposit metal free from objectionable oxide inclusions, the deoxidizers when applied as a core or coating acting very inefiiciently in the arc.

I have found that cleaner deposits can be obtained by properly choosing the deoxidizers and alloying them in proper proportions with iron or steel to form a welding rod or electrode; that by proceeding in this way I can deposit clean metal even when the proportion of deoxidizers is not so great as to prevent their being practically eliminated during deposition; and that the deposited metal has the characteristics of carbon steel.

Deposits having the characteristics of carbon steel are intended in the specification and claims to refer to alloys composed mainly of iron except carbon, manganese, silicon and minor impurities, the carbon being not more than 0.5%, manganese not more than about 1.0%, and silicon not more than about 0.5%.

As deoxidizers, to be alloyed with iron to produce the rod material, I may use vanadium or zirconium, or both of these elements. Manganese and silicon are used in conjunction with the deoxidizers. Carbon may be present in quantities ranging from insignificant traces to about 0.6%, depending on the proportion of this element which is desired in the deposit.

As examples of suitable proportions of deoxidizing elements, I may state that about 1% of vanadium or zirconium may be used, or a corresponding total of both of these elements. The silicon may be about 0.3% to 1.5% and the manganese may range from about 0.5% to 3.0%. Slightly greater variations of silicon may be used with vanadium, namely from about 0.25% to about 1.5%. At least 0.7% manganese is preferable in rods which contain zirconium and in those which contain vanadium with silicon in smaller amounts. The composition may be varied within the above limits to suit particular conditions, but for general purposes rods containing about 1.5% silicon, about 1.0% manganese, about 1% of deoxidizing metal or metals (vanadium or zirconium) and about 0.2 carbon give excellent results.

The rods of my invention are especially suitable for use with arcs carrying 200 amperes and upward to insure rapid deposition. With low currents it is necessary to play the are on the deposited metal to refine the latter and burn out the alloying'constituents. Arcs carrying 450 amperes give excellent results, and the current may be increased to 600 amperes or more. The higher the current, the more rapidly the non-ferrous components of the rod are consumed and the more rapidly can the welding be completed. Larger proportions of deoxidizers are best suited for the heavier arcs. The rods of the invention produce voluminous slags and it is desirable to employ the heat generating properties of electric arcs to keep the pools of deposited metal properly molten.

Arc welding with the described rods which contain the smaller amounts of silicon, manganese and vanadium and/or zirconium is more rapid than with the use of combustion torches. Welds can be made with combustion torches when the 35 latter rods are used under the most favorable welding conditions but the most reliable results cannot be obtained in practice. Deleterious amounts of the alloy ingredients of the rods, oxide inclusions or weak joints are common causes of failure where combustion torches are used. With the largest amounts of alloy ingredients, combustion torches cannot be used. Increases in the alloy constituents of the rods or less favorable .welding conditions while applying the heat from combustion torches to the puddles of deposited metal, increase the chances of defective deposited metal or complete failure to form welds. Large amounts of slag are always produced in welding with the rods of the invention. The slag hinders the conduction of heat to the weld when combustion torches are used.

In arc welding, the heat generated under the layer of slag by the action of the current, supplies the necessary heat to refine the metal which is violently oxidized during its passage through the arc, and the thick layer of slag avoids an excessive rate of oxidation and cooling after the deposit is made; On the other hand, the oxidizable slagforming and. deoxidizing elements are present in substantially of carbon steel, plying electric current to an kind, quantity and proportions suiflcient to permit wide variations in the conditions which are commonly present in welding, such as the thick-. ness of plates, the size of the rod, and the size of the puddle of deposited metal.

With rods containing the lower proportions of silicon, manganese, vanadium and/or zirconium, high welding speeds can be attained with the arc.

' When the amounts of these elements in the rods are below the minima set herein, uncertain results are, obtained by reasonof oxide inclusions. With the highest currents and the best welding conditions, silicon, manganese, vanadium and/or zirconium may be increased somewhat beyond the highest limits specifically mentioned. It is to be understood that the statement of the upper limits of these elements in the specification and claims is not intended to exclude such variations.

I claim:

1. The method of producing welds which consist which comprises apelectrode so as to produce an arc of at least 200 amperes, and feeding to the are an alloy rod which is composed mainly of iron and contains carbon the carbon being less than about 0.6%, about 0.3% to 1.5% silicon, about 0.5% to 3.0% manganese, about 1.0% of 'at least one of the following elements? vanadium, zirconium.

2. The method of producing welds which. consist substantially of carbon steel, which comprises applying electric current to an electrode so as to produce an arc of at least 200 amperes, and

feeding to the are an alloy rod which is composed mainly of iron and contains about 0.2% carbon, about 1.5% silicon, about 1.0% manganese, about 1.0% vanadium.

3. The method of producing welds which consists; substantially of carbon steel, which comprises applying electric current to an electrode so as to produce an arc of at least 200 amperes, and feeding to the are an alloy rod which is composed mainly of iron and contains about 0.2% carbon, about0.25% to 1.5% silicon, about 0.5% to 3.0% manganese, about 1.0% vanadium. JAMES M. KEIR.