Brake rotor material

[Cement Legs]

Does anyone have any info on what type of material (specifically... ie steel doesnt help http://fsae.com/groupee_common/emoticons/icon_smile.gif ) that rotor manufacturing companies use? Second, for any teams out there that have had success machining their own rotors, what material have you used

Cheers

[Cement Legs]

Does anyone have any info on what type of material (specifically... ie steel doesnt help http://fsae.com/groupee_common/emoticons/icon_smile.gif ) that rotor manufacturing companies use? Second, for any teams out there that have had success machining their own rotors, what material have you used

Cheers

[Andy Horner]

we used 1018 steel, cold drawn as well as ductile iron grade 80-55-06 to make our rotors and had no problems with them both

[MikeWaggoner at UW]

You can machine them out of other car's brake rotors. It can be a little tricky finding solid discs big enough, but it's possible.

[rjwoods77]

I was looking into Al-MMC rotors. I found a place i can get them at a resonable price. Everything i read and here suggest that they will hold up and they are almost as light as aluminum. Machining isnt hard really. Just gotta blanchard grind them to make sure the surfaces are paralell.

[bigfella]

We've been using Al-MMC rotors for the last two years, no dramas. Just watch your pad material selection.

[Kevin Hayward]

Grey Cast Iron is cheap, easily formed, has good thermal properties, low wear rates and is dimensionally stable at high temperatures. Also given that cast iron s the most common brake rotor material a lot of pads will work well with it.

Probably worth considering what the braking conditions are for the car when looking at materials. You can have quite a lot of decent brake applications in a FSAE vehicle in a very short time frame. Consistent material properties under a range of temperatures is a pretty important factor.

Kev

[madman]

To add to Kev's comments, most commercial car brakes (outside exotic ceramic/graphite racing brakes) use varying grades of grey cast iron.

However most commercial companies then do their own tweaking with the alloying compounds (usually copper, manganese and nickel - and course carbon) to get the desired low thermal expansion and maximum conductivty.

There are some good papers on the subject kicking around. There's a nice one by a Japanese group who looked at the bullet train brakes and characterised the optimum quantities of the varying alloying elements.

Check your local Grey cast iron seller and they should have a couple of grades in their catalogue that list "brake rotor material" under the "uses" section. That's a good start. Then the rest is up to your design process.

Of course, the auto manufacturers also like grey cast iron for its manufacturing properties and cost. Both of which are not such a huge factor in FSAE. So, if you're clever about your design, there are other materials with potential benefits....

Essay over - back to work.
Brian

[Cement Legs]

Thanks guys, I'll see if my local metal dealer has a catalogue listing for grey cast iron for brake use http://fsae.com/groupee_common/emoticons/icon_smile.gif.

[rjwoods77]

Hey bigfella,
I am looking at machining down some Al-MMC rotors for another application but I dont have the specs yet and don't know if they will fit my needs. This company will supply me with the correct pad compound for Al-MMC. Is there a place they sells plates of the stuff i can cut and shape the way i need? Where or who do you get your s from? Would they be able to help me out?

[Wright D]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MikeWaggoner at UW:
You can machine them out of other car's brake rotors. It can be a little tricky finding solid discs big enough, but it's possible. </div></BLOCKQUOTE>

We have solid brake rotors by the bundle where I work,www.peterdmotorsports.com; they would be perfect for cutting down and using in an fsae car. We replace them with our own rotors, so we have plenty lying around.

I have a cad drawing of them in unaltered, stock condition. They are just over 10 inches in diameter, and can be turned down from their 11mm thickness. Two brake rotors cost $32.00 plus shipping.

[Jersey Tom]

3/16" HRS -&gt; waterjet -&gt; brake rotor. Bingo bango.

[Wright D]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jersey Tom:
3/16" HRS -&gt; waterjet -&gt; brake rotor. Bingo bango. </div></BLOCKQUOTE>

That is an option but you loose all of the cool properties that cast iron has.

Where I work we turn down cast iron rotors, and then have them water jet cut. This gives us the best of worlds, easier manufacturing and good material properties.

Mild steel has positives too though, it tends to not crack.

[Jersey Tom]

Eh. Quick, easy, cheap, and hooks up enough to brake to at least 1.3G over a couple years without replacement. I call it good.

[RonBurgundy01]

We have been using mild steel rotors for the past couple of years without any problems at all. As for the manufacturing...we got a custom pattern laser cut using a material that is 1mm thicker than the desired rotor size then very very gradually machined them back. Got to be a bit careful on the machining though coz you don't want to heat the material too much without need.