INCONEL? alloy 751 (UNS N07751) is a precipitation hardenable nickel-chromium alloy, used mainly for the exhaust valves of internal combustion engines. Its limiting chemical composition is shown in Table 1. The alloy has essentially the same excellent physical, mechanical and corrosion-resistance properties as INCONEL alloy X-750. Some physical constants for INCONEL alloy 751 are shown in Table 2. Its thermal properties correspond closely to those published for INCONEL alloy X-750. In the evaluation of materials for exhaust valve applications, nickel-chromium alloys have performed well in a 1675°F (913°C) lead oxide screening test. INCONEL alloy 751 repeatedly offered good results, with corrosion rates averaging 4.31 g/dm2 /h. Like other nickel-chromium alloys, INCONEL alloy 751 also resists attack by other exhaust stream impurities such as sulfur, bromine and chlorine. Table 1 - Limiting Chemical Composition, % Nickel (+ Cobalt) ..........................................................70.0 min. Chromium....................................................................14.0-17.0 Iron ..................................................................................5.0-9.0 Titanium...........................................................................2.0-2.6 Aluminum ........................................................................0.9-1.5 Niobium (+ Tantalum) ......................................................0.7-1.2 Manganese ...................................................................1.0 max. Silicon ...........................................................................0.5 max. Sulfur ..........................................................................0.01 max. Copper..........................................................................0.5 max. Carbon........................................................................0.10 max. Publication Number SMC-083 Copyright ? Special Metals Corporation, 2004 (Sept 04) INCONEL is a trademark of the Special Metals Corporation group of companies. The data contained in this publication is for informational purposes only and may be revised at any time without prior notice. The data is believed to be accurate and reliable, but Special Metals makes no representation or warranty of any kind (express or implied) and assumes no liability with respect to the accuracy or completeness of the information contained herein. Although the data is believed to be representative of the product, the actual characteristics or performance of the product may vary from what is shown in this publication. Nothing contained in this publication should be construed as guaranteeing the product for a particular use or application. Physical Constants and Thermal Properties Table 2 - Physical Constants & Thermal Properties Density, lb/in3 .....................................................................0.297 g/cm3 ......................................................................8.22 Melting Range, °F .....................................................2540-2600 °C .....................................................1390-1430 Specific Heat, Btu/lb °F.....................................................0.103 J/kg °C .........................................................431 Curie Temperature, °F .........................................................-193 °C ........................................................-125 Permeability at 200 oersted (15.9 kA/m).........................1.0035 Coefficient of Expansion, 10-6 in/in °F (μm/m °C) 70-200°F (21-93°C) ..............................7.0 (12.6) Thermal Conductivity, Btu in/ft2 h °F......................................83 W/m °C........................................................12.0 Electrical Resistivity, ohm?circ?mil/ft ...................................731 μ? ohm?m..........................................1.22 Young’s Modulus, 103 ksi .......................................................31 GPa................................................................214 Modulus of Rigidity, 103 ksi....................................................11 GPa..................................................................76
