As the opening ceremony for the 2012 Olympics gets underway this evening, the world of gases and welding will be front and center in two of the games’ most anticipated and iconic elements—the Olympic torch and the Olympic Stadium. Hydrogen vehicles also play an interesting role in the 2012 London Olympics.

London's Olympic Stadium is 75% lighter than previous Olympic venues, thanks to the use of lightweight steel.

The Olympic Stadium
In years past, Olympic venues have been designed as monuments, something to remember for years to come. Take the Beijing National Stadium built for the 2008 Olympic games (the Bird’s Nest, as it has come to be known). The stadium with its whimsical steel frame—and 45,000 tons of steel in all—will no doubt be remembered. But the dig on Olympic venues is that they often serve little function after the games.

With this in mind, London’s Olympic Stadium looks to make a very different kind of statement than those of years past. During the 2012 games, the Olympic Stadium will seat 80,000 people. 55,000 of those seats are temporary. After the games, the stadium will be partly disassembled to create a smaller 25,000 seat venue. In fact, the builders didn’t even bother to cover the bolts used to hold the steel together, knowing that they will eventually be removed.

One of the keys to creating a stadium that could be transformed was the use of lightweight steel. In total, the Olympic Stadium contains just over 11,000 tons of steel (a far cry from Beijing’s 45,000), making it the lightest stadium in the world at this size. Also of note is the fact that the top ring of the stadium was built using 2,500 tons of reclaimed surplus gas pipes from the North Sea Gas Pipeline project.

The ArcellorMittal Orbit includes steel from five contintents.

As with any stadium construction, the Olympic Stadium relied on skilled welders to join the lightweight steel. One welder left his mark—and a good-luck charm for his home country—by welding a series of horseshoes that resemble the Olympic rings into the stadium’s roof. You can read more about how Construction Manager Steve Burley welded his creation 120 feet up on a pillar here.

Elsewhere in the Olympic Park, the Aquatics Centre (where swimming events will be held) stands out with its 525-foot-long wave-shaped steel roof, which rests on just three supports.

One of the most distinctive buildings at the 2012 London Olympics is the Orbit (officially the ArcellorMittal Orbit), an observation deck that doubles as a piece of public art. ArcellorMittal donated all of the steel for the project, sourcing the supplies from five different continents (including North America) in the global spirit of the Olympics. Just over 2,400 tons of steel were used in its construction, including 60% recycled steel.

The Olympic Torch
Arguably the most iconic symbol of the Olympics, this year’s Olympic torch is made from a special aluminum alloy originally developed for the aerospace and automotive industries. The alloy’s characteristics make it heat resistant, lightweight and strong.

The torch has a unique triangular design incorporating a complex pattern of 8,000 holes (representing the 8,000 people who carried the torch on its journey from Olympia, Greece, to London). Along with their symbolic representation, the holes are functional. One of the torch’s designers, Jay Osgerby , says, “The wind moves through the torch, the perforations allow the metal to cool, and so the torch never gets hot.”

The Olympic torch relies on laser welding and cutting processes.

In creating the torch, the holes are cut from the alloy using a numerically controlled 2D laser cutting machine. After this, the manufacturer uses 3D laser technology to weld the parts of the torch together in a smooth, seamless joint and cut additional holes in the welded areas.

As for the actual flame, the 2012 torch uses a gas mix including two-thirds propane and one-third butane. Each of the 8,000 torches used this year (yes, they use a separate torch for every runner) has enough gas to burn for 13-14 minutes, although it only takes 3-6 minutes for each carrier to travel the 300 meters (328 yards) of each leg.

Scroll down to view a video of the torch’s construction.

Hydrogen Vehicles at the Olympics
Recently it was announced that five hydrogen taxis will be used to transport VIPs in London throughout the Olympics. The fleet will refuel at London’s Heathrow airport at a new Air Products fueling station.

Meanwhile, London’s fuel cell buses, which have been running since 2009 (and recently hit the milestone of 100,000 miles driven), are being decommissioned during the Olympic due to security concerns. The Air Products hydrogen fueling station in East London used to operate the buses was originally approved in 2009 on the condition that hydrogen fuel not be stored on-site between July and mid-September of 2012.

Notably, a fleet of 20 hydrogen buses was used successfully and without incident at the 2010 winter games in Vancouver, Canada.

With or without hydrogen buses, the gases and welding industry will be well represented at the 2012 games. As promised, here is a video showing the manufacture of the Olympic Torch.

Photos: London 2012, ArcelorMittal