I have just found this article which discusses research into using high strength stainless steel in car chassis, which could give weight saving and safety benefits:
www.outokumpu.com/pages/Page____37404.aspx
"...Under the umbrella of the Next Generation Vehicle project, NGV for short... ...Using the B-pillar (a key structural member of a car body) from Volvo S40 as a benchmark, they came up with two different designs, some 20 percent lighter than the conventional pillar. When crash-tested, the behavior of stainless steel was discovered to be very good, albeit different from ordinary steel..."
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Stainless, Aluminium alloys and Carbon fibre all can be made to work, but the issue is and remains that for cars in the cheaper price brackets (under £20k) they work out too expensive.
I guess the plant making these cars has to be tooled up to handle stainless, which is a major expense. Given that rust is not an issue in treated steel cars, as you say, weight saving is the main reason to look at this material but I assume Aluminium - magnesium alloys are much better
for this property.
However car makers are often innovative, so it will be interesting to see what emerges from Volvo.
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Stainless Aluminium alloys and Carbon fibre all can be made to work but the issue is and remains that for cars in the cheaper price brackets (under £20k) they work out too expensive.
but I assume Aluminium - magnesium alloys are much better for this property.
Aluminium is actually cheaper than stainless steel.
Not sure how much metal there is in a Golf (cheapest car it would be viable in), looking at this though:
www.meps.co.uk/Stainless%20Prices.htm
Looks like a tonne costs as much as £5k, compared to a few hundred pounds for cheap steel. Not sure how much car steel costs though.
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They'll need to increase the zinc everywhere else or the carbon steel will corrode that much quicker!
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Rich 9-3
i refer you to thread " Why 3-door cars? " read it all please especially my bit on 5 door shells being stronger than 3 doors (i was specific on a mk2 escort but to be honest it equally applies to most cars unless the floor pan is crossed braced at manufacture) you will notice i was accused of sniping for having an opinion so i would be interested in your views on the subject of car strength in the motor parc
i thank you
note i kept my words to an absolute minimum apart from this very long bit to apologise for the length of the post talking about the post i was talking about
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>>i was accused of sniping for having an opinion
No, you were accused of sniping for your derision of anything that comes from a text book or journal, rather than from the "wisdom" of the workshop floor.
Number_Cruncher
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the "wisdom" of the workshop floor.
Why the quote marks NC?
I am sure that on reflection you will not deny the existence of a valid form of practical wisdom stemming from much hands-on experience. Bell boy like virtually everyone who posts here has strong prejudices and opinions but isn't one of the backroom's notable snipers.
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As for structural use of stainless steel, my understanding is that although it is strong it can be brittle, is far less malleable than mild steel so difficult to work by stamping and so on, is difficult to weld and is intrinsically more expensive to make. Stainless parts unless very simple often show evidence of much machining.
Of course cars are getting more expensive anyway, so perhaps we will see more of it.
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In reply to Lud's message.
Regarding working stainless steel - thats my impression as well, hence why I said the tooling for a plant making such cars maybe more expensive as some of the welding eqpt and presses may need to be changed rather than just changing the molds/dies/templates and ronbot programming.
However I am not a Car manufacturing expert, so someone in the industry may no differently.
However Audi manage with aluminium alloys.
Re Aluminium price - is pure Aluminium used to make cars or is it an alloy ? is the alloy dearer than stainless?
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Re Aluminium price - is pure Aluminium used to make cars or is it an alloy ? is the alloy dearer than stainless?
Pure aluminium is next to useless for making structural parts, it's always an alloy that's used.
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Maybe sniping wasn't quite the right word, and I'm sorry if any offence has been taken. What I was trying to point out was that his poor view of engineering theory, text books, and journals, is, to say the least rather short sighted.
There's a workshop based view that I have been aware of - my father exemplified it marvellously! - where anyone who gets knowledge from a book is "book learnt", and this isn't good, and that only on the job experience actually counts. IME, to be a good engineer, you need a bit of both. Many people leaving university engineering courses only have the book learning, and so their use is much more limited.
However, I'm wary of people who waffle on about how much experience they have. When someone says they have 30 years experience, does that mean they have been accumulating knowledge and wisdom for 30 years, or that thet they learnt the job in a year, and then repeated it 29 times! There are some who gain more real experience in 2 years than most seat warmers gain in 20.
I'm not completely belittling experience, but I don't think that it alone is the be all and end all. By looking at books and journals, effectively you can easily gain some knowledge and understanding that others got the hard (and expensive!) way.
Number_Cruncher
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Rich 9-3 i would be interested in your views on the subject of car strength
Fraid I am not qualified to comment BB, in this thread I am merely a messenger.
I work in construction and know a bit about structural eng but nothing about mech eng. The level of structural design I get involved in would probably be comparable to a Ford Model T level of chassis development!
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probably be comparable to a Ford Model T level of chassis development!
I could probably stretch to designing a Model A chassis so I'm clearly more expert than you ;-)
It says in the article that the crash behaviour is different to mild steel, which is no surprise to any of us who paid a bit of attention in materials science class, or have bent a stainless part back and forth until it breaks.... However car designers now have sophisticated finite element programs so it shouldn't be that complicated to predict what will happen and redesign the part to suit.
Stainless can be welded to mild steel I understand, but I've never tried it. And as said above, I'd be interested to see if there's a corrosion issue with the less noble metal.
Saving weight is one thing, but it all comes down to cost. I'm sure there are engineers out there who are trying to get the cost down using other materials, like the Audi A8 with it's light but expensive aluminium and (for petrolheads with a good memory) the Panther Solo with it's carbon fibre shell
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DeLoreans are stainless.
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DeLoreans are stainless.
The body on the Delorean was Stainless, but was the Lotus derived chassis?
Although crash standards have changed significantly since it was designed.
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Deloreans are plastic. The stainless panels are just stuck on the outside.
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Saving weight is one thing but it all comes down to cost.
Yes thats the big question isnt it, there is no mention of relative cost in the article..
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