The automotive exhaust conditions are partially related with engine because these cannot be specifically defined and are not consistent to choose the base material. Normally, automotive exhaust comprises of a mixture of carbon monoxide, oxides of nitrogen,unburned hydrocarbons and moisture. The temperatures operate the gamut from ambient to 1800oF gas velocities are high, the internal combustion engine cause pulsation of the gas stream and vibration of the device and the operation is fully cyclic.

The issue is further intensified by the various levels of expertise on the users side and people operating the engine that results in the operating conditions that exceed design expectations and probable temperatures. Combining these conditions with the enduring commitment to tighten automotive emissions, simultaneously decrease weight and the exhaust system no longer resembles the old systems comprising essential cast manifold, pipe and muffler. While steel neither plain, galvanized or aluminum coated, has performed well, designers are now indicating the Stainless Steel Sheet that are more competent of adhering in the oxidation and corrosion conditions at the elevated temperatures in these new systems, and choosing alloy that also offer good elevated temperature strength.

For example, steel grade 409, generally recommend as the muffler grade stainless steel, was one of the first to be utilized broadly in the auto exhaust systems, specifically for catalytic converters that are installed on the several US made cars.The steel grade 409 is also used for the various exhaust gas ducts in turbochargers and it is a good choice for mufflers and tail pipe parts. in the specific applications, although steel 409 may not offer adequate creep strength, in which situation a more concentrated alloyed stainless steel like one of the austenitic or new ferritic grades can be more suitable. A standard example is a converter-turbocharger combination in which higher pressures cause increased temperature limits.

The Stainless Steel Sheet 304L is now utilized broadly for exhaust gas coolers, that are small heat exchangers utilizing engine coolant to decrease the temperature of small volume exhaust gas recycled through the fuel intake. The cool inert gas helps to decrease the oxides of nitrogen. The low carbon grade is known to avoid sensitization while elevated temperature brazing of the cooler components while assembly.

Since the exhaust system engineers comer closer to get a practical deign for a fabricated sheet metal that will operate at temperature more than the cooler or catalytic converter, other stainless steels or high nickel grade alloys are chosen,. In brief, the exhaust system manufacturing programs are in full strength at all automotive companies and component producers and the broad range of alloys are considered including those were earlier in states of commercial development.