Moderator: Mike Simanyi
Why do aluminum cylinder heads work for years?Marshall Grice wrote:you can find charts of yield strength vs temp and then apply that to fatigue vs yield strength in the MIL-HDBK.Andrew Bingham wrote: And none of the references I can find easily talk about the effect of temperature exposure on fatigue life, which is important.
long story short, aluminum becomes mush at elevated temperatures.
Thermal conductivityMike Simanyi wrote: Why do aluminum cylinder heads work for years?
Bonus question: how do they get Teflon to stick to the pan?
Heat treating is a critical step in the aluminum manufacturing process to achieve required end-use properties. The heat treatment of aluminum alloys requires precise control of the time-temperature profile, tight temperature uniformity and compliance with industry-wide specifications so as to achieve repeatable results and produce a high-quality, functional product.
http://www.keytometals.com/article39.htm" onclick="window.open(this.href);return false;The effects of age hardening or precipitation hardening on mechanical properties are greatly accelerated, and usually accentuated, by reheating the quenched material to about 212˚F-424˚F (100˚C-200˚C). A characteristic feature of elevated-temperature aging effects on tensile properties is that the increase in yield strength is more pronounced than the increase in tensile strength. Also ductility – as measured by percentage elongation – may decrease. Thus an alloy in the T6 temper has higher strength but lower ductility than the same alloy in the T4 temper
Cylinder heads - Different Aluminum alloyMike Simanyi wrote:Why do aluminum cylinder heads work for years?
Bonus question: how do they get Teflon to stick to the pan?
Teflon coating: http://www.finishing.com/2200-2399/2252.shtml" onclick="window.open(this.href);return false;Aluminum-copper cast alloys (2xx.x series)
Cylinder heads for automotive and aircraft engines, pistons for diesel engines, exhausting system parts.
Aluminum-silicon-copper/magnesium cast alloys (3xx.x series)
Automotive cylinder blocks and head, car wheels, aircraft fittings, casings and other parts of compressors and pumps.
Many kinds of Teflon can be applied to a few thousands thick. It is a baked product, so you have to make sure that the aluminum does not lose its properties at that temp. Not knowing your application, there is a 50-50 probability that it will not work well for you.
(note a lot of the answers on that page also include the fact that attention must be paid to application or the material and if the teflon coating process will change the aluminum properties in an undesireable way)You can Teflon aluminum with DuPont PFA, PTFE, ETFE, TEFLON S, and FEP. All have different properties and different cure temps. It depends on what usage and environment the piece is going to be used for. you also can use Ausimont's Halar ECTFE. Another process could be to anodize, then use Nituff Teflon.
