Mild Steel
Density: 0.283lb/in2
Tensile strength: 55,000lb/in2
Yield strength: 40,000lb/in2
Elongation: 20%
Modulus of elasticity: 29.5 x 106lb/in2
Coefficient of thermal expansion: 7.228in/in-F x 106
Coefficient of thermal conductivity: 26.98BTU/ft-hr-F
MILD STEEL is easy to bend and to fabricate but has its drawbacks, for example high weight and poor resistance to oxidation, far outweigh its positive qualities. We would not recommend this metal to the committed enthusiast or the serious racer.
304 Stainless Steel
Density: 0.29lb/in2
Tensile strength: 85,000lb/in2
Yield strength: 35,000lb/in2
Elongation: 55%
Modulus of elasticity: 28 x 106lb/in2
Coefficient of thermal expansion: 9.9in/in-F x 106
Coefficient of thermal conductivity: 9.40BTU/ft-hr-F
STAINLESS STEEL 304L is a durable material for most manifolds or exhaust systems and it is an excellent metal for use either on race or road engines. 304L is a perfect upgrade for mild steel as it provides superior performance, improved visual appearance and vastly increased durability.
321 Stainless Steel
Density: 0.290lb/in2
Tensile strength: 90,000lb/in2
Yield strength: 25,000lb/in2
Elongation: 55%
Modulus of elasticity: 29 x 106lb/in2
Coefficient of thermal expansion: 9.6 in/in-F x 106
Coefficient of thermal conductivity: 9.3 BTU/ft-hr-F
STAINLESS STEEL 321 is one of the most durable stainless materials because of its high Nickel content and the presence of Titanium. These metals give it excellent fatigue resistance to cracking at high temperatures. It is therefore our recommended material of choice for turbocharger applications.
Asnex Titanium
Density: 0.163lb/in2
Tensile strength: 50,000lb/in2
Yield strength: 40,000lb/in2
Elongation: 20%
Modulus of elasticity: 0.163 x 106lb/in2
Coefficient of thermal expansion: 4.8in/in-F x 106
Coefficient of thermal conductivity: 12BTU/ft-hr-F
ASNEX HIGH TEMPERATURE TITANIUM Ti-1.2
ASNEX has excellent high temperature oxidation resistance and practical fonnability.
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Titanium is the material of choice for those who wish to upgrade from stainless. It will give a reduction in weight of approximately 2/3rds over the weight of stainless. We would not normally recommend it for an entire system but mainly for the components where the temperature does not exceed 400°C for sustained periods of time. ASTM Grade 2 Titanium offers the optimum in terms of cost, availability, fabrication, weldability and mechanical properties.
Inconel
Density: 0.305lb/in2
Tensile strength: 140,000lb/in2
Yield strength: 77,000lb/in2
Elongation: 47%
Modulus of elasticity: 0.305 x 106lb/in2
Coefficient of thermal expansion: 5.5in/in-F x 106
Coefficient of thermal conductivity: 5.65BTU/ft-hr-F
INCONEL 625 contains 60% Nickel and 22% Chromium. Initially it was developed to cope with the extreme heat and very high strength demands of jet engines but it is now routinely used on Formula 1 engine manifolds. Inconel is the ultimate material of choice for the high end requirements of motorsport.
