During the 2020 Bahrain Grand Prix, when Romain Grosjean’s Haas vehicle separated into two pieces and caught fire, the titanium halo was instrumental in saving his life. However, many remain unaware of the innovative welding method that significantly enhanced the strength of the halo, ensuring it could function effectively at that critical juncture.
The halo, which is now a crucial component of Formula 1’s safety measures, encountered significant resistance upon its introduction in 2018. Nonetheless, numerous notable incidents—such as Grosjean’s spectacular crash, Zhou Guanyu flipping during the race at Silverstone in 2022, and the collision between Verstappen and Hamilton at Monza in 2021—have effectively quieted those objections. This protective element for the driver’s compartment has consistently demonstrated its value.
However, few realize that producing the halo according to the FIA’s stringent safety requirements—able to bear the tremendous loads it could encounter—was an enormous technological hurdle. It needed to support the weight equivalent of a London double-decker bus, which conventional techniques were unable to achieve. This necessitated using premium-quality titanium along with impeccable, cutting-edge welding procedures to maintain the integrity of the material.
The difficulty of welding titanium
By the end of 2017, the companies that participated in the FIA’s tender for the production of the halo – including the party that ultimately won the contract – did not have the in-house technical capabilities to weld the five titanium parts of the halo to the highest possible quality. That’s when they turned to LKN WeldTitan, the titanium-specialized division of Dutch company LKN WeldCompany BV. After nearly four weeks of intensive research and development, they succeeded in welding the parts together in a way that completely preserved the titanium’s technical properties, ensuring that the halo met FIA’s stringent standards.
“Diamond-like resilience comes from titanium’s nature as a reactive metal; this characteristic causes it to interact with atmospheric components—even at room temperature—leading to oxidation,” clarifies Patrick Wouterse, who founded and runs LKN WeldCompany, during an interview with GaptekZone. “This behavior renders titanium extremely durable against corrosive forces since a slim oxide coating develops almost instantly, safeguarding the underlying material—a trait that positions titanium perfectly for use within the chemical sector.”
Zhou Guanyu’s Alfa Romeo C42 crashes at the beginning of the race.
Photo by: Mark Sutton / Motorsport Images
However, beyond the halos’ protective features, their primary attribute isn’t merely rust prevention; rather, it’s the balance between durability and lightness. As Wouterse elaborates, “The specific grade 5 titanium utilized for these halos stands out because it offers superior tensile strength compared to steel yet weighs considerably less.” He further explains, “To achieve equivalent structural integrity with stainless steel would require three times as thick material—say, needing fifteen millimeters of stainless steel where five millimeters of titanium suffice instead.” This exceptional characteristic makes this metal highly favored within aviation industries and thus an obvious choice for constructing robust yet lightweight safety cages in vehicles. The objective here is always about achieving maximum sturdiness without compromising overall vehicle mass.
Nonetheless, welding titanium requires great care because heating this metal makes it highly susceptible to increased reactivity. It readily absorbs gases such as oxygen and hydrogen “as easily as a sponge soaks up water.” The tiniest amount of contamination—such as minuscule particles of dust or residual oil from fingerprints—can severely compromise the integrity of the titanium at the site of the weld.
“As soon as titanium takes in these elements, it alters the metal’s composition and significantly reduces its strength by up to 75% in the compromised region,” says Wouterse. “To avoid this, you must ensure that during welding, no additional elements come into contact with the metal.”
The innovation: perfect welding within a purging enclosure
Typically, welders use a localized stream of an inert gas such as argon to safeguard the molten metal. However, this approach isn’t sufficient when working with titanium. As Wouterse explains, “Heat spreads outwards; even the nearby materials can get up to 1,000 degrees Celsius. Yet, titanium begins absorbing oxygen once temperatures hit merely 150 degrees.”
You can observe the damage directly—the titanium alters color. A silver hue signifies that the properties remain undamaged, whereas gold suggests only a minor and permissible degradation. However, should it turn blue, purple, or green, the material is effectively compromised.
Titanium halo
Image courtesy of: LKN WeldCompany BV
Wouterse and his team dedicated several years to refining a distinct welding technique. They also constructed specialized welding purge chambers, ensuring that the welding occurs within an environment filled with inert gas.
Although it seems straightforward—just place the components in a box and flood it with argon—it’s actually incredibly intricate,” explains Wouterse. The challenge lies in the persistent presence of trace amounts of oxygen within the purging environment. “Primarily, we introduce argon, helium, and neon into the chamber; however, due to their differing weights—with argon being heavier than both oxygen and helium—even minor movements like handling items through the glove boxes can disturb the gas layers and elevate the oxygen content.
Wouterse goes on to say, “We needed methods to reduce the oxygen levels to mere parts per million. Even factors like the chamber’s design and the type of wall finishes can influence the outcome, making this an incredibly complex task. Additionally, there are at least fifteen other elements that must also be precisely controlled for us to achieve the desired measurements.”
In the last twenty years, Wouterse has focused extensively on this procedure. By means of LKN WeldCompany BV, he has established a robust standing, which has resulted in worldwide requests for his firm’s proficiency in specialized welding tasks spanning sectors like aerospace, energy, chemicals, nuclear power, pharmaceuticals, and automobiles. Furthermore, Wouterse is often engaged by businesses for process enhancement and quality assurance.
Following contact initiated through a shared acquaintance between FIA’s halo supplier and LKN, the firm based in Amersfoort engineered a specialized welding chamber capable of accommodating the complete halo jig. This was essential due to the intricate, asymmetrical hollow nature of the component. Wouterse recounts, “Once we validated our method under EN ISO guidelines, constructed a prototype, and put it through testing—it surpassed the stringent criteria set forth by the FIA.” He continues, “Subsequently, we swiftly progressed to manufacturing mode. By early 2018, we had completed welds on the initial batch comprising one hundred halos destined for Formula 1 use.”
Romain Grosjean, driving for Haas F1, escapes from the fire following a terrifying collision at the start of the Bahrain Grand Prix; marshals rush to assist at the scene.
Photo credit: Andy Hone / Motorsport Images
A life-saving legacy
For Wouterse, witnessing the effectiveness of the halo system—particularly during incidents such as Grosjean’s crash—is incredibly gratifying. “Naturally, one always hopes for safety and no severe accidents. However, when they do occur, it’s reassuring to see the halo installed on those vehicles. This gives me great satisfaction knowing that ‘we were part of developing this,’” he says with evident enthusiasm.
In particular during the early stages, numerous individuals despised the halo—they considered it unattractive, with several drivers claiming it impaired their vision. However, following the initial major accident where the halo proved crucial, all the backlash ceased. Everybody concurred that it was indeed the correct decision.
Grosjean’s accident had a profound impact on Wouterse. “If you examine the simulations created following the event, you can observe how the halo bent the barrier just sufficiently to shield Grosjean’s head. Had it not been for this device, he would not have lived through the incident. Additionally, thanks to the integrity of the halo, he managed to exit from the blazing debris.”
Afterward, Wouterse actually exchanged messages with Grosjean. “I contacted him via LinkedIn and clarified our involvement with the halo. He responded saying, ‘In that case, I suppose I should thank you.’ Being an avid Formula 1 supporter myself, this was particularly meaningful.”
Towards the end of this year, Wouterse intends to go to the F1 Exhibition in Amsterdam to view Grosjean’s charred chassis firsthand—a potent testament to the lifesaving technology that he and his team contributed to refining.
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