IT ALL STARTS WITH TI­TA­NIUM

F1 Racing (UK) - - PRO -

– and plenty of it.

“We had to buy about ten tonnes of high­strength ti­ta­nium within one-and-a-half months, and re­ceive it all in time and in per­fect con­di­tion,” says St­ef­fen Zacharias of Ger­many’s CP Au­tosport, one of the three man­u­fac­tur­ers cho­sen by the FIA to be of­fi­cial sup­pli­ers of the new halo safety de­vice.

‘High strength’ means Grade 5 ti­ta­nium, which is used ex­ten­sively in the aerospace in­dus­try owing to its near-op­ti­mal bal­ance be­tween struc­tural stiff­ness and weight. But this comes at a cost, and not just in terms of ex­pen­di­ture on raw ma­te­ri­als: ti­ta­nium is a dif­fi­cult and de­mand­ing ma­te­rial with which to work, which is why so few man­u­fac­tur­ers made it through the ten­der­ing process. “We have a long his­tory in mo­tor­sport, hav­ing been in­volved since the 1990s, but we have an even longer back­ground in aerospace ma­te­ri­als and fab­ri­ca­tion,” says Zacharias. “We’ve been build­ing ti­ta­nium parts for aerospace and for outer space – for the EU’S Ari­ane rocket pro­gramme – and this back­ground is where we come from and it’s how we ended up in For­mula 1.”

This ex­pe­ri­ence put CP on pole when it came to pro­duc­ing the halo pro­to­type for FIA test­ing. Along­side the UK’S SSTT and Italy’s V Sys­tem, CP were tasked with build­ing a pro­to­type within 6.5 weeks to be tested at the UK’S Cran­field Tech­ni­cal Cen­tre in Oc­to­ber 2017. They were the first com­pany to pass the test and have been cho­sen by nine of the ten F1 teams to sup­ply ha­los this sea­son – although some teams have pur­chased de­vices from all three com­pa­nies.

It helps that CP’S man­u­fac­tur­ing fa­cil­ity was ideally suited to the task. “You need state-ofthe-art ma­chin­ing parts to do the pre-ma­chin­ing and the post-weld­ing fi­nal ma­chin­ing,” ex­plains Zacharias. “You need a weld­ing cham­ber in a closed at­mos­phere for the weld­ing process, and you need the sup­ply chain for the ma­te­rial.”

One of the key chal­lenges with ti­ta­nium is that it has to be heat-treated to achieve op­ti­mal strength be­fore you start work­ing it. CP gen­er­ally re­ceive forged blocks that have been pre-treated to an in­di­vid­ual spec­i­fi­ca­tion to help with­stand the loads the fin­ished de­vice will face.

“We’ve been given a chal­leng­ing load case to which the halo should per­form in the phys­i­cal test,” says Zacharias. “One thing to give a part func­tion is the ge­om­e­try, but when it comes to weld­ing and met­al­lurgy the heat-treat­ment process is one of the key driv­ers. With the heat treat­ment you set up the phys­i­cal strengths of the part in com­bi­na­tion with the ge­om­e­try.”

The next step is to pre-ma­chine and gun­drill the tubes that will be welded to­gether. The halo it­self is built from five dif­fer­ent parts. The half-ring at the top is made from two quar­ters of the cir­cle. Then there are the two end pieces that at­tach to the back of the car and the cen­tre pil­lar in front of the driver. The weld­ing process is per­formed in a closed cham­ber to pre­vent any foreign ob­jects con­tam­i­nat­ing – and there­fore weak­en­ing – the joins. The whole de­vice then un­der­goes fur­ther heat treat­ment for ad­di­tional strength­en­ing be­fore it’s sent for test­ing.

“The chal­lenge is in form­ing the tube in this ti­ta­nium Grade 5 con­di­tion with­out weak­en­ing it,” says Zacharias. “And then hav­ing the heat treat­ment in the right setup. Heat treat­ment is one of the tech­ni­cal tricks you need to bring in to make the parts work as they’re sup­posed to.”

Only the ref­er­ence pro­duc­tion de­vice is tested to de­struc­tion at Cran­field. Each sub­se­quent de­vice is made from an ex­act process sheet that is ap­proved by the Global In­sti­tute for Mo­tor Sport Safety, the FIA’S safety re­search part­ner. But ev­ery de­vice is ge­om­e­try-checked, weightchecked and un­der­goes non-destruc­tive test­ing, in­clud­ing x-rays and crack bench­marks.

“We do these in-house,” says Zacharias. “Com­ing from the aerospace in­dus­try, we have a very in­tense test­ing area, in­clud­ing phys­i­cal test benches and life-cy­cle test­ing. All our parts are tested in-house by cer­ti­fied peo­ple to an aerospace stan­dard.”

The x-ray test in­volves an ap­proved en­gi­neer screen­ing all of the weld­ing seams, and this is fol­lowed by a dyepen­e­tra­tion test to check for any cracks in the ma­te­rial. Then an ul­tra­sonic probe as­cer­tains whether the wall-thick­ness of the tube is the same at ev­ery point. No area is left unchecked.

Once com­plete, the halo is man­u­ally shot­cleaned to cre­ate an abra­sive sur­face that makes it eas­ier for teams to at­tach any aero­dy­namic parts that are per­mit­ted by the FIA. This does not mod­ify the strength of the ma­te­rial or put any stress on the parts.

All of these steps are es­sen­tial to pro­duc­ing such a high-per­for­mance de­vice. The halo has to with­stand 125kn of force (equiv­a­lent to 12 tonnes in weight) from above for five sec­onds with­out a fail­ure to any part of the sur­vival cell or the mount­ings. It must also with­stand forces of 125kn from the side. With­out ques­tion, it’s now the strong­est el­e­ment on an F1 car.

“It’s been a task to bring it all to­gether,” says Zacharias. “We’ve been pro­duc­ing ti­ta­nium struc­tures for years, but to bring it all to­gether – the ma­chin­ing, the gun-drilling of the ma­te­rial to pro­duce a tube with such wall thick­ness, the weld­ing process and ge­om­e­try from all five parts com­ing to­gether, and the heat-treat­ment process – to meet this pre­cise win­dow of tech­ni­cal func­tion, that was the main task. Each field it­self was like what we’ve been used to, but to nail it down in 6.5 weeks was the hard­est task.”

It helped that the F1 teams were fully sup­port­ive at ev­ery step of the way. “I’ve been in this busi­ness now for al­most 20 years and I’ve never ex­pe­ri­enced such an open-door phi­los­o­phy from the teams,” ad­mits Zacharias. “Ev­ery door has been opened.” Clearly the teams have been do­ing ev­ery­thing they can to help in­te­grate the halo into the de­sign of their cars. Although one pri­or­ity dur­ing de­vel­op­ment was to min­imise weight, it was in­evitable – given the im­pactre­sis­tance de­mands – that the halo would add bulk to the chas­sis. Each one weighs 7kg, which in it­self isn’t a great deal, and yet it’s 7kg that wasn’t pre­vi­ously po­si­tioned so high on the car.

“Adopt­ing it has been a sig­nif­i­cant chal­lenge,” says Mercedes tech­ni­cal di­rec­tor James Al­li­son. “It’s sev­eral kilo­grams of ti­ta­nium that needs to be put on the car, and all of the changes that we needed to do to ac­com­mo­date it had to be made so that the over­all car would still stay be­low the weight limit.”

And although the halo func­tions like a bolt-on de­vice, to achieve max­i­mum ef­fec­tive­ness it has to be fit­ted to a chas­sis specif­i­cally de­signed to ac­cept the kind of loads it might trans­mit. Al­li­son ex­plains: “We had to strengthen the chas­sis so that it would take roughly the weight of a dou­bledecker bus sit­ting on top of the halo to make sure it’s strong enough to with­stand the type of event it’s de­signed to pro­tect the driver’s head against.”

That’s why each team has bought sev­eral ha­los, some from all three sup­pli­ers, to eval­u­ate dur­ing the de­sign process. As al­ways in F1, the pur­suit of the per­fect pack­age is an un­ceas­ing whirl of mar­ginal gains.

By the end of March, CP were ex­pect­ing to have pro­duced and shipped 100 ha­los. Not only are they sup­ply­ing nine of the ten F1 teams, they are also sup­ply­ing the F2 and For­mula E cham­pi­onships, which are then dis­tribut­ing to their teams. F2 is adopt­ing the halo this year, while For­mula E will fea­ture it on the Gen2 car that makes its de­but next sea­son. Other se­ries will fol­low. And this level of vis­i­bil­ity will rep­re­sent a new world for a com­pany such as CP.

“We have 200 peo­ple work­ing here and we usu­ally pro­duce parts that are un­der­neath the car and cov­ered up by car­bon fi­bre,” says Zacharias. “So to be able to show a phys­i­cal part that’s more vis­i­ble to the pub­lic means our em­ploy­ees can say: ‘This is what we’ve been work­ing on, and this is what drives me to stay longer to ful­fil my job and over­come ob­sta­cles that oth­ers may be stopped by.’ So yeah, that re­ally makes us proud.”

First pub­lished in the FIA’S AUTO mag­a­zine

“WE USU­ALLY PRO­DUCE PARTS THAT ARE UN­DER­NEATH THE CAR AND COV­ERED UP BY CAR­BON FI­BRE.

TO BE ABLE TO SHOW A PHYS­I­CAL PART THAT’S VIS­I­BLE TO THE PUB­LIC RE­ALLY MAKES US PROUD”

CP Au­tosport weld their ha­los in a closed at­mos­phere to avoid any ex­ter­nal con­tam­i­na­tion that could weaken the joints

The forged block of ti­ta­nium is milled into the halo’s five com­po­nent parts be­fore un­der­go­ing fur­ther heat-treat­ment cy­cles to add strength

Ev­ery halo is made from a process sheet that is ap­proved by the Global In­sti­tute for Mo­tor Sport Safety, the FIA’S safety re­search part­ner

CP Au­tosport are sup­ply­ing nine of F1’s ten teams in F1 with ha­los, although some teams have also bought ha­los from SSTT and V Sys­tem

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