We don’t normally see stainless steel cars but Tesla’s making their new Cybertruck out of stainless steel. This is another bold move from a company that likes to rip up the rulebooks. You can read all about the Cybertruck here.
But is it actually a good idea?
Why has only one other stainless steel car been mass-produced, and that ended in bankruptcy? Will it be different for Tesla, or is the new Cybertruck a big white elephant?
An English metallurgist, Harry Brearly, was trying to improve rifle barrels just before the first world war. He found that adding chromium to steel inhibited its natural tendency to rust. This is because of a chromium-rich oxide coating that seals the metal from the elements.
But it wasn’t until the 1930s that people thought of using stainless steel on cars. The Allegheny Ludlum Steel company approached Ford Motor Company with the idea of a car to help them sell more stainless steel.
Ford obliged and produced 6 unpainted Ford Model 68 Deluxes. Allegheny Ludlum loaned them out each year to their top salesmen. The cars were on the road for ten years and each one of them logged in over 200,000 miles.
The shiny bodies are still in excellent condition, of course, and have held up better than the rusting steel chassis! Why the chassis was not made from stainless steel is a mystery.
But here’s the first reason as to why we don’t see more stainless steel cars on the road. A retired Allegheny Ludlum employee revealed that when the cars were originally produced the dies were ruined by stamping out the stainless steel parts from the harder material.
So, to produce cars from stainless steel, carmakers must spend additional money. Making dies that could withstand stamping out stainless steel parts day in, day out. The Tesla Cybertruck uses cold-rolled stainless steel. And that’s even harder than regular stainless steel, and this makes the problem even worse.
Ford agreed to another collaboration with Allegheny Ludlum in 1960 to produce two Ford Thunderbirds. These original 1936 cars had been very shiny. But with the update, they went for a brushed finish, and I’m sure other motorists thanked them for it!
After the issue with dies with the 1936 cars. Ford waited until the end of the car’s production run before damaging the dies producing the stainless steel cars! Again, Allegheny Ludlum used it to help publicize stainless steel and they toured the USA drumming up business.
The new cars used stainless steel exhausts and mufflers. They must be the only 1960s cars still around today with their original exhausts! Ford and Allegheny Ludlum collaborated one last time with three stainless steel 1967 Lincoln Continental convertibles.
If you want to see all three in their glory, you can find them at the Crawford Auto-Aviation Museum in Cleveland, OH.By the 1950s mainstream car manufacturers were dabbling with stainless steel, making small car parts such as hubcaps. GM went one step further in 1958 with the Cadillac Eldorado Brougham which featured a stainless steel roof.
They did the same to the 1979 Cadillac Eldorado Biarritz. The European car Maserati made their 1971 Bora with a stainless steel roof along with stainless steel windscreen pillars. But each part was a simple shape, to make production easier.
It would take a maverick car company executive to build a whole car from stainless steel. And that person was John DeLorean. A young high-flying GM vice president who one day quit his job to start his own car company.
He decided his first, and only, car, the DMC DeLorean would be brushed stainless steel. The DeLorean Motor Company was probably the only car company without a paint shop!
Only three cars sold to customers would be anything other than plain brushed stainless steel, and those were plated with 24-carat gold!
Yes, a company mad enough to put gull-wing doors on a car decided it would be a good idea to make a car that was covered entirely in real gold!
The car’s finish looked a little rough up close. But it had the advantage that small scratches could be taken out with a non-metallic scouring pad. Never worry about getting your car “keyed” ever again!
However, some customers didn’t like the unfinished stainless steel look, so took their cars to a paint shop to get the color they wanted. GMC had a brief and turbulent history, ending in receivership and bankruptcy in 1982. Great Scott!
The fabled Gold Plated, Stainless Steel Delorean carBut stainless steel cars had several disadvantages that have kept them from wider adoption:
It seems silly to put this as a disadvantage, but to car companies who’ve built their entire business around selling you a new car every five years or so, having a car that doesn’t decay isn’t that great.
There are also Government incentives that encourage customers back to car dealers every few years. With tight profit margins, many car companies rely on things like leasing agreements to stay in business, and changing that may cause the business unforeseen financial problems.
Stainless steel is more expensive than regular steel, and when margins are so tight, why add extra cost to the vehicle?
As we talked about before, stainless steel is a harder metal, which makes it harder to form the final shape for the car. It’s also more difficult to weld.
With a steel car, if there’s a dent you can use filler and paint to hide the problem With stainless steel, especially unpainted stainless steel, the only option is to try to restore it to its original shape, which is hard enough with regular steel, but harder with tougher stainless steel.
Most stainless steel cars produced weren’t painted at all, because let’s face it, they didn’t need to be. But to many people, choosing the color of their car is a big part of the process. There’s a good reason why Fords come in more than black these days!
And if you’re going to paint the car, then the car looks no more different from normal car bodies that were becoming much more rust-resistant by the late 1970s. People don’t want to stand out, but they want to be individualistic, at least in a more subtle way.
Car companies did this by first getting better at rustproofing. Then they started galvanizing the metal, and companies like Audi started making their bodies from aluminum which doesn’t rust anyway, and it’s softer than steel so easier to form.
Aluminum welding is trickier, but over time they’ve found ways to master it. So, this brings us to Tesla’s Cybertruck. They’ve opted to go for an even harder form of stainless steel – a grade they’ll use on the SpaceX Starship – so let’s see how those same disadvantages stack up.
Tesla isn’t as affected by making a car that will last more than five years before needing to be replaced. As we mentioned before, steel car bodies don’t rust like they used to, and the other components of a Tesla look like they’ll last ten years or more. Tesla’s a company in expansion, so it’s less reliant on repeat business from its customers.
This will still impact Tesla, but they’ll use less metal as the stainless steel body will be used as a stressed member to make the car more rigid. And with a starting price of $40,000, it seems the added cost of stainless steel isn’t going to impact the final car price very much.
There’s a good reason the Cybertruck is all angles. Instead of bending the metal, it’s simply cut out and welded together. Tesla and SpaceX are learning to weld this material on an industrial scale, and like Audi with aluminum, they believe that they can solve the problem.
This one may be harder to solve. Tesla’s claiming the Cybertruck can withstand some major impacts, so maybe fender benders just won’t be a big issue. But larger repairs could be a major expense, and repair shops will need to learn a whole new set of skills.
That very strength could be an issue when the car’s released. Elon stated in the Cybertruck reveal that the body “is literally bulletproof to a nine-millimeter handgun”.
It’s likely that we start to see more exotic materials come into the mainstream, there are various alloys out there plus there’s carbon fiber, it’s been around for close to 60 years and there’s still no way to mass-produce the stuff for cars. But that could change soon.
Look around the factory floor and, as sure as day, a gleaming array of metallic instrumentation and machinery will be staring back at you. Were it not for some incredibly versatile metals, much of these tools, and the products and services that the Process Industry specialises in simply couldn't be produced on a mass industrial scale. PIF examines the advantages and disadvantages of several metals commonly used in manufacturing.
Advantages: The most abundant metal in the Earth's crust, Aluminium is relatively soft, durable, lightweight, ductile and malleable metal. It acts as a good thermal and electrical conductor and is also fairly corrosion resistant. Plus, it is theoretically 100% recyclable without any loss of its natural qualities and remarkably nontoxic.
Disadvantages: It's not particularly strong and is expensive compared to steel of the same strength.
Applications: Aluminium is almost always alloyed to improve its properties. It is commonly used in the transportation, construction and packaging industries.
Advantages: Bronze is an alloy consisting mainly of copper but the addition of other metals (usually tin) produces an alloy much harder than plain copper. Bronze resists corrosion and metal fatigue better, and conducts heat and electricity, better than most steels.
Disadvantages: Bronzes are generally softer, weaker and more expensive than steel.
Applications: Bronze is widely used for springs, bearings, bushings, automobile transmission pilot bearings and is particularly common in the bearings of small electric motors.
Advantages: Carbon steel's main alloying constituent is carbon. Low carbon steel is the most common and cost effective form. It contains around 0.05–0.320% carbon and is malleable and ductile. Medium carbon steel contains between 0.30–0.59% carbon and balances ductility and strength with good wear resistance. High-carbon steel has 0.6–0.99% carbon content and is exceptionally strong, while ultra high carbon steel contains 1.0–2.0% carbon and can be tempered to great hardness.
Disadvantages: Low-carbon steels suffer from yield-point runout and mild steel has a relatively low tensile strength.
Applications: Medium carbon is used for large parts, forging and automotive components. High-carbon steel is used for springs and high-strength wires. Ultra high carbon steel is used for special purposes like knives, axles or punches.
Advantages: Nickel belongs to the transition metals. It is hard, ductile and considered corrosion-resistant because of its slow rate of oxidation at room temperature. It also boasts a high melting point and is magnetic at room temperature.
Disadvantages: Handling nickel can result in symptoms of dermatitis among sensitized individuals.
Applications: Nickel is valuable for the alloys it forms and roughly 60% of world production goes into nickel-steels. Specific uses include stainless steel, alnico magnets, coins, rechargeable batteries, electric guitar strings, microphone capsules, and special alloys. It is also used for plating and as a green tint in glass.
Advantages: Titanium is corrosion resistant and has the highest strength-to-density ratio of any metallic element. Unalloyed it's as strong as some steels but less dense. Its relatively high melting point (more than 1,650 °C or 3,000 °F) makes it useful as a refractory metal. It is also paramagnetic and displays fairly low electrical and thermal conductivity.
Disadvantages: Costly and laborious processes are needed to extract titanium from its various ores.
Applications: Titanium can be alloyed with iron, aluminium, vanadium, and molybdenum (among others) to produce strong, lightweight alloys. These are used in the aerospace, military, industrial process, automotive, agri-food, medical, and sporting industries to name but a few.