Weld It!

Today the U.S. is building ships, soon at a rate of two or even three a day, with speed and economy that was inconceivable in World War I--and building them better.

Today 1040's tight machine-tool bottleneck is being broken.

Tomorrow the U.S. may begin building steel airplanes as light as today's welded aluminum planes.

All these things have become possible because of steady but unadvertised advances in the science and art of welding. For the use of welding has made the major difference between the U.S. arms smithing of 1941-42 and 1917-18.

In sheer racket the shipyards of 1918 were rivaled only by the Western Front, for into every 10,000-ton freighter were battered over a half-million rivets. In many modern ships nearly all these rivets have been eliminated. Result is that shipyards today are much quieter, and to gapers outside their guarded walls the chief evidence of activity within is the firefly flashing of arc welders clambering among the hulls.

Even the steel frames of factories and shipways now abuilding are quietly welded together. Silenced for good is the awful din of the structural riveter who clattered up against the U.S. sky in the '20s, a splendid symbol and at the same time an infernal nuisance.

Technological Revolution. Unlike soldering, welding does not consist merely of sticking two objects together with metal glue. Instead it fuses them into one piece, almost as if they were recast. The village blacksmith did a crude form of welding when he heated two iron rods to the melting point and hammered them together till they fused, but modern welding is a much more efficient operation.

Commonest form of welding used today is arc welding. An arc welder has for his tool a device that holds a pencil-sized metal rod carrying a heavy (around 200 amps) electric current of low voltage. When he brings the rod close to the metal to be welded, the current leaps across the near-contact, forming a blinding arc whose temperature--some 6,500DEG F.--melts both the rod and the metal being welded into tiny molten pools which quickly cool into solid metal. Since the welder's rod (called an electrode) melts down like a candle, he carries a quiverful of rods with him as he works.

A welded product is strongest at its welds. Reason: as the high-grade steel in the melting electrode is deposited, it is protected--as the mill-rolled steel which is being welded was not protected--from contamination by the air's oxygen and nitrogen. These are excluded by another gas formed by the electrode's coating (paper pulp and sodium silicate), which shields the melting metal from the air.

So hot is the welding arc that if it is held more than an instant on one spot, it will eat a hole through a thick steel plate. With his brilliant sputtering arc always in motion, a masked welder "knits" a seam by laying molten steel deposits endlessly atop each other.

Some welding on ships was attempted in World War I, but its failures impressed engineers more than its successes: no protective coating for the rods had been developed, so the arcs were not gas-shielded, and the welded seams were of inferior metal; the arcs' temperatures were hard to control, and welded plates often heat-warped. Development of the arc-shielding coating by Milwaukee's A. O. Smith Corp. at last gave arc welding the reliability it needed.

In shipbuilding, welding:

> Saves man power hence cost. One welder can assemble as much steel as a four-man riveting team. Since only some 20% of the required skilled labor was on hand when the defense shipbuilding program began, it was four times as efficient to train welders as it would have been to train riveters.

> Saves 13% deadweight in a ship's hull, and proportionally increases the vessel's carrying capacity. Weight reduction comes from elimination of 1) overlap of a ship's plates--welded they lie butt to butt, 2) angle-pieces often required in riveted joints, 3) the rivets themselves.

> Saves time, because large hull sections can be welded together in shops, then hauled & hoisted to the ways and welded into a complete hull. In shops welding is quicker than in the ways, since a welder can easily reach difficult spots and never has to weld over his head with molten steel drops raining down on his mask and shoulders. Formerly, a keel was laid in the ways and riveters started at the middle and worked slowly toward each end of the ship, because the plates had to be staggered and overlapped in an intricate patchwork. The 530,000 rivets in a typical 1918 freighter filled perhaps as many as 1,500,000 rivet holes, whose bothersome drilling can now be eliminated wherever welding is used.

> Saves materials (and further weight) because absence of rivet holes, which weaken sheet steel, means that plates and beams can be cut from thinner steel.

> Saves building many new shipways. Now, when much construction takes place in shops, a typical ship occupies its ways about five months--instead of eight months during World War I.

These amazing, interrelated economies have made welding the greatest bottleneck smasher in U.S. shipbuilding. Welding is being used wherever possible, but some riveting still goes on. Reason: shortage of welders, and the existence of riveting skills and equipment which it is not yet wise to junk. In 1918 some 16% of a ship yard's personnel were riveters. Today the average is about 1%.

Steel-framed buildings. In land construction welding's methods and savings are similar to those in shipbuilding. Welded structural steel is 7 to 10% cheaper than riveted -- an economy which guarantees that riveting will never echo again in U.S. cities. Increasingly common in recent years, welded steel frames would have supplanted riveted buildings five or ten years sooner in most cities had not backward building commissions feared that welding was some sort of tinsmith's soldering.

Machine tools. Casting is being nudged aside too by arc welding, notably in the machine-tool industry. Welding allows the frames of huge presses, drills, saws, etc., to be built of smaller pieces rather than cast in large chunks which then have to be cut, shaped and finished. Welding can cut by 25% (average) the time and cost of manufacturing the $450,000,000 worth of machine tools required yearly by the arming U.S.

Resistance welding in its several forms, like arc welding, has made notable contributions to defense production. Commonest form is spot welding: two pieces of thin metal are fused together by the heat generated, due to their electrical resistance when an electric current passes through them. Unlike arc welding, melting of the current-feeding electrode is avoided by: 1) making the electrode partly of copper, whose resistance is very low; 2) mixing the copper, through powder-metal techniques (TIME, Sept. 29), with compounds whose melting point is far higher than steel's; 3) cooling the electrode with water.

Widely used in auto-building, spot welding is today spreading through the aviation industry now that the problems of welding aluminum have been outwitted.-- Engineer Paul H. Merriman of Glenn L. Martin Co. estimates that when spot welding has captured the entire aircraft industry--with perhaps 60 welds applied in one movement of a machine--U.S. plane output will increase by 30%.

Shotwelding is a refinement of spot welding designed for stainless steel (usual formula: 18% chromium, 8% nickel), whose great tensile strength--four times that of ordinary carbon steel--is lost when it is heated to 1,100DEG to 1,600DEG. The Shotwelding electrodes stab the metal for 1/10 th 1/20 th of a second, heating it so instantaneously through its danger zone to its 2,700DEG fusing point that the alloy's unique strength is not affected. Invented by Budd Manufacturing Co. (and used for making stainless steel railroad coaches), Shotwelding may well make steel planes lighter than even welded aluminum planes.

Detroit's William B. Stout, an aeronautical engineer whose visions have often come to pass, observed last week:

"Aluminum weighs one-third as much as steel, but [stainless] steel is more than four times as strong as aluminum in pull and tension. Recent developments in structure mathematics now enable us, even in small planes, to build trusses of thin stainless steel of equal weight to duralumin [an alloy containing 95% aluminum, 4% copper, 1/2 % manganese and 1/2 % magnesium while in larger ships there is a greater advantage to the steel construction.

"The art of building a featherweight, superstrength, welded steel structure is growing at a tremendous rate. It is my prediction that all future commercial planes and most military planes will be made of welded steel."

-- The chief problems: 1) aluminum has a low melting point (1220DEG F.); 2) it oxidizes ("rusts") easily when hot.

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