50 Fun Facts About Welding

Until the end of the 19th century, what was the only process available for joining iron and steel?

Blacksmiths joined iron and steel by heating and hammering for millennia. The Iron Pillar of Delhi, from around 400 CE, was made this way.

The earliest known welding dates to which period?

Small gold boxes made with pressure-welded lap joints survive from that era. Forge welding of iron came later, in the Iron Age.

Which scientist discovered the short-pulse electric arc in 1800, laying the groundwork for arc welding?

He presented the results in 1801 and rediscovered the continuous arc in 1808, unaware that Vasily Petrov had already done so in Russia.

Nikolay Benardos introduced the first practical arc welding method in 1881. What kind of electrodes did it use?

He developed it with Polish engineer Stanisław Olszewski in a French lab; they received a British patent in 1885. He called the process Elektrogefest.

The first patents for resistance welding, in 1885, went to which American inventor?

He kept improving it for 15 years. His company later merged into General Electric.

Oxygen-acetylene welding was first developed in 1903 by engineers from which country?

Edmond Fouché and Charles Picard. Acetylene itself had been discovered by Edmund Davy in 1836.

An oxy-acetylene flame burns at roughly what temperature?

That is about 6,300 °F, hotter than oxyhydrogen (2,800 °C) or propane-oxygen (about 2,250 °C).

What is the chemical formula of acetylene?

Its systematic name is ethyne. It is usually produced from calcium carbide and water.

Around 1900, Oscar Kjellberg and Arthur Strohmenger introduced what innovation to arc welding?

Kjellberg dipped iron wire in carbonates and silicates; Strohmenger used clay and lime. Kjellberg went on to found ESAB.

What is the informal name for SMAW, the manual process that uses a flux-coated consumable electrode?

The flux coating on the consumable electrode burns off to make shielding gas and slag. It still dominates maintenance and repair work.

In stick welding, what two protective by-products come from the disintegrating flux coating?

Both keep atmospheric oxygen and nitrogen out of the molten pool. The slag is chipped off afterwards.

MIG and MAG are subtypes of which process?

MIG uses inert gas, MAG uses an active gas like CO2. The arc forms between a consumable wire electrode and the workpiece.

Gas metal arc welding was developed in 1948 by which US research organisation?

It initially needed costly inert gas; the 1953 switch to carbon dioxide made welding steel with it economical.

The use of CO2 as a GMAW shielding atmosphere was developed in which year?

It quickly caught on because it made welding steel far cheaper than pure argon or helium.

TIG welding uses an electrode made of what?

The electrode is non-consumable; filler is added separately. TIG is slower and harder to master but ideal for thin stainless and aluminium.

TIG welding was originally called Heliarc because early versions used which shielding gas?

Northrop engineers devised it in the early 1940s to weld the magnesium XP-56 aircraft. Argon is the usual choice today.

What is the melting point of the TIG-electrode metal, the highest of any element?

That is 6,192 °F. It also has the lowest vapour pressure and highest tensile strength of any pure metal.

Which noble gas is the most common inert shielding gas in welding?

It is chemically inert under almost all conditions and forms no confirmed stable compounds at room temperature.

In submerged arc welding, what is the arc 'submerged' beneath?

The flux is a mix of lime, silica, manganese oxide and calcium fluoride that becomes conductive when molten. The first patent dates from 1935.

Who invented friction stir welding at TWI in 1991?

Wayne Thomas devised it. A rotating non-consumable tool stirs the two pieces together in a solid state.

Electron-beam welding is usually performed in what environment?

The vacuum stops the beam scattering. German physicist Karl-Heinz Steigerwald built the first practical machine, operating from 1958.

Plasma arc welding was invented in 1957 by whom?

The same year saw the debut of flux-cored arc welding. Plasma cutting is a spin-off of the process.

Exothermic (thermite) welding heats metal using a reaction between a metal oxide and powdered what?

The aluminothermic reaction needs no external power. It is the standard way to join railway rails; the Delaware and Hudson tested it in 1935.

Thermite welding is most widely used to join what?

The rail ends are preheated to orange heat with a torch so the molten steel is not chilled during the pour.

What temperature is the usual dividing line between soldering and brazing?

Both use a filler with a lower melting point than the base metal, unlike welding, which melts the parent metal itself.

In brazing, what draws the molten filler metal into the joint?

Clearances of 0.03 to 0.08 mm give the best results. Braze welding, by contrast, uses no capillary action.

Spot-welding electrodes are usually made from which low-resistance metal?

The heat comes from resistance to current at the contact point. An ordinary car can contain several thousand robot-made spot welds.

The modern welding helmet was first introduced in 1937 by which company?

The auto-darkening filter came much later: Sweden's Hornell International launched the Speedglas LCD shutter in 1981.

The first auto-darkening welding filter, Speedglas (1981), came from which country?

Hornell International's LCD shutter darkens the instant sensors see the arc. The brand is now owned by 3M.

The painful eye condition welders call 'arc eye' is medically known as what?

It is essentially sunburn of the cornea from ultraviolet light, and skiers and mountaineers can get it from snow glare.

The American Welding Society was founded in which year?

Comfort Adams brought industry leaders together after World War I to merge two wartime welding bodies; he served as its first president.

Which shipbuilder launched the first ocean-going ship with an entirely welded hull, the Fullagar?

A wartime gas shortage pushed British yards toward arc welding. The Titanic, by contrast, sank partly through failures in its riveted hull.

How many welded Liberty ships did American yards build between 1941 and 1945?

About three ships every two days. Nearly 1,500 suffered serious brittle fractures; Constance Tipper showed the steel, not the welds, was to blame.

Cambridge scientist Constance Tipper showed that Liberty ship fractures were caused by what?

The cracks did not start in the welds; below a certain temperature the steel simply switched from ductile to brittle.

Underwater hyperbaric welding was invented in 1932 by a metallurgist from which country?

Konstantin Khrenov. 'Wet' welding happens in the water itself; 'dry' hyperbaric welding uses a pressurised enclosure.

Welding was first attempted in space in 1969 by cosmonauts on which mission?

They tested shielded metal arc, plasma arc and electron beam welding in a depressurised compartment.

Cold welding, where clean metal surfaces bond in space, is blamed for a 1991 problem on which spacecraft?

The high-gain antenna's ribs stuck and it never fully opened. The European Space Agency published a paper on the risk in 2009.

The rust-resistant Iron Pillar of Delhi, built under Chandragupta II around 400 CE, was made how?

It stands 7.21 metres tall in the Qutb complex and has barely corroded in 1,600 years.

Ultrasonic welding of rigid plastics, patented in 1965, was first applied in which industry?

Robert Soloff and Seymour Linsley held the patent; Soloff had been welding plastic films into bags at Branson Instruments.

The area next to a weld whose microstructure has been altered without melting is called what?

HAZ cracks can appear as late as two days after welding, which is why inspection is not always immediate.

Gas bubbles trapped in a solidified weld are a defect known as what?

Other defects include cracks, lack of fusion, incomplete penetration and undercutting.

The English word 'weld' is thought to derive from a Scandinavian word meaning what?

The Swedish for the raw material of wrought iron is välljärn, literally 'boiling iron'.

What was the M/S Carolinian, launched in 1930, the first of its kind to be?

Time magazine reported that nine workmen built it in a fraction of the usual time, saving 75% of the cost and 77,000 pounds of steel rivets.

Which famous building's iconic shape rests on a stud-welded steel frame?

Stud welding was released by Kyle Taylor in 1930 and quickly became popular in shipbuilding and construction.

Which process joins materials by slamming them together under extremely high pressure?

The impact plasticizes the metals with little heat, which is why it is used to bond dissimilar materials like aluminum to carbon steel in ship hulls.

In what year was electroslag welding introduced?

Its cousin, electrogas welding, followed three years later in 1961.

Roughly how many spot welds can an ordinary car contain?

Most of them are made by industrial robots, which is why spot welding was the first big application of robot welding.

What is the name for the region of a weld where the filler metal was actually laid down?

Its properties depend mainly on the filler metal and how compatible it is with the base materials around it.

In WWII shipbuilding, submerged arc welding sped up certain welds by what factor?

The process had been invented in 1930, the same year stud welding was released.

Solvent welding joins thermoplastics using what instead of heat?

It is one of several alternatives to fusion, alongside solid-state methods like cold welding and diffusion bonding that bond without melting.