Re: Spraying water on brakes
+1
'The Great White'
Red_Bean_Bun;560130 said:
+1
'The Great White'
Spraying water on brakes
- Thread starter RaidenGear
- Start date
Re: Spraying water on brakes
hahahahah u joker.... the metal will fatigue and crack!!!! Long time no see ya!
wilman2772;560132 said:+1
'The Great White'
hahahahah u joker.... the metal will fatigue and crack!!!! Long time no see ya!
Re: Spraying water on brakes
No lah.....unless you drive straight into a swimming pool or into the sea..........
Or get into this...
[ame=http://www.youtube.com/watch?v=0h-sYDf5FSk]YouTube - The Wave Song (With Lyric and Sing along) - MrBrown Show Production.mp4[/ame]
'The Great White'
richlee7;560133 said:
Carcinogenic;560134 said:
No lah.....unless you drive straight into a swimming pool or into the sea..........
Or get into this...
[ame=http://www.youtube.com/watch?v=0h-sYDf5FSk]YouTube - The Wave Song (With Lyric and Sing along) - MrBrown Show Production.mp4[/ame]
'The Great White'
Re: Spraying water on brakes
It's technically different...i ll tell u why....
on rainy days, you wont do enthusiastic drive and your brakes will tend to be cooler anyway because of that plus the weather....you can stil probably touch ur rotors w/o burning ur fingers...
in hot days with spirited driving n bit of hard braking, that's completely different stories..
it's clearly damaging your rotors.
Slater;559942 said:
It's technically different...i ll tell u why....
on rainy days, you wont do enthusiastic drive and your brakes will tend to be cooler anyway because of that plus the weather....you can stil probably touch ur rotors w/o burning ur fingers...
in hot days with spirited driving n bit of hard braking, that's completely different stories..
it's clearly damaging your rotors.
Breyton
Well-Known Member
Re: Spraying water on brakes
My material science knowledge is somewhat hazy now (perhaps someone who did it less than 15 years ago can correct me if I'm wrong).
The brake discs on road cars are generally made from gray cast iron and typically experience up to a max temp of around 600 deg C. Gray cast iron has its first phase-transition temperature at 740 degrees C. Below this, the material is in a phase called 'ferrite'. Above this, depending on the amount of carbon present, there is a mixture of a phase called austenite and graphite.
And why is the phase relevant? Because this 'spraying of water' thing is somewhat like a process in materials science called 'quenching', where materials are heated up and then dipped in liquid to quickly bring the temperature down, allowing the material to contain phases that would otherwise not be present if allowed to cool normally. Eg. if you quench gray cast iron you may get a mixture of austenite and ferrite. This mixture of phases give rise to internal tension/compression forces, which may contribute to 'warping' of the material.
So for gray cast iron below 740 deg C, there really is no such effect since it is still all in ferrite phase. As far as rentention of microstructure and shape, I wouldn't be too worried about spraying water on a hot disc. What I might be worried about is it will contribute to the fatigue cycles of the disc - the rapid expansion and contraction. All iron and steel suffer from a phenomenon called 'fatigue' where repeated cycles of loads, even though below the material's failure load, will still cause the material to fail. As ship builders and aircraft manufacturers catastrophically found out years ago.
Read an article somewhere that what most people think is 'warping' of their discs, is more due to hotspots on the disc or pad (localised regions with higher temps than the rest of the disc/pad) causing uneven deposits of pad material on the disc. Think it was written by some race engineer who said he very rarely encountered real disc warping, even for race applications.
My material science knowledge is somewhat hazy now (perhaps someone who did it less than 15 years ago can correct me if I'm wrong).
The brake discs on road cars are generally made from gray cast iron and typically experience up to a max temp of around 600 deg C. Gray cast iron has its first phase-transition temperature at 740 degrees C. Below this, the material is in a phase called 'ferrite'. Above this, depending on the amount of carbon present, there is a mixture of a phase called austenite and graphite.
And why is the phase relevant? Because this 'spraying of water' thing is somewhat like a process in materials science called 'quenching', where materials are heated up and then dipped in liquid to quickly bring the temperature down, allowing the material to contain phases that would otherwise not be present if allowed to cool normally. Eg. if you quench gray cast iron you may get a mixture of austenite and ferrite. This mixture of phases give rise to internal tension/compression forces, which may contribute to 'warping' of the material.
So for gray cast iron below 740 deg C, there really is no such effect since it is still all in ferrite phase. As far as rentention of microstructure and shape, I wouldn't be too worried about spraying water on a hot disc. What I might be worried about is it will contribute to the fatigue cycles of the disc - the rapid expansion and contraction. All iron and steel suffer from a phenomenon called 'fatigue' where repeated cycles of loads, even though below the material's failure load, will still cause the material to fail. As ship builders and aircraft manufacturers catastrophically found out years ago.
Read an article somewhere that what most people think is 'warping' of their discs, is more due to hotspots on the disc or pad (localised regions with higher temps than the rest of the disc/pad) causing uneven deposits of pad material on the disc. Think it was written by some race engineer who said he very rarely encountered real disc warping, even for race applications.
Breyton
Well-Known Member
Re: Spraying water on brakes
Most engineering faculties will have material science as part of its syllabus - mechanical, civil, aeronautical, etc. Need to know how to select the materials as well as know the limits of materials when you design something. I found the modules interesting, but I'm pretty sure I wouldn't have been able to take doing purely materials science!
Most engineering faculties will have material science as part of its syllabus - mechanical, civil, aeronautical, etc. Need to know how to select the materials as well as know the limits of materials when you design something. I found the modules interesting, but I'm pretty sure I wouldn't have been able to take doing purely materials science!
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