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	PRODUCT DATA of IMI 550

Material	IMI 550
Product Datasheet	IMI550
General Information	TIMETAL 550 is a medium strength, forgeable alpha beta alloy. In the solution treated and aged condition, the alloy has superior tensile and fatigue properties compared to TIMETAL 6-4 combined with good elevated temperature tensile strength and creep properties up to 750°F (400°C). TIMETAL 550 has applications in the aerospace industry, both as aeroengine and airframe components. Typical applications include compressor discs and flap tracks. The alloy has also found applications in high performance automotive engines.
Chemical Composition	4% Al, 4% Mo, 2% Sn, 0.5% Si Rem. Ti
Name of Manufacturer	TIMET The Hub,Holford Road, Witton, Birmingham B6 7AX, UK +44 121 356-1155 EuroSales@timet.com +44 121 356-5413 www.timet.com

	EXPERIENCE IN PRACTICE

Development Status	Commercial Product
Cost Range	Low to Medium
Equivalent Designations	Timetal 550, Ti-550, AFNOR TA4DE, Werk. No. 3.7185, CEN Ti P68
Space Experience	Good

	PHYSICAL PROPERTIES

Specific Gravity	4.6 Remark:@ Room Temperature
Magnetic Properties	Nonmagnetic

	ELASTIC PROPERTIES

Tensile Modulus

110 to 120 GPa Data Quality: Manufacturer's data

	ELECTRICAL PROPERTIES

Electrical Volume Resistivity

0.00000159 ohm.m Remark: Data Quality: Manufacturer's data

	THERMAL PROPERTIES

Thermal Conductivity	7.52 W/m.K Remark:@ Room Temperature Data Quality: Manufacturer's data
Thermal Expansion Coefficient	8.8 μstrain/°C Remark: From 20 to 200C Data Quality: Manufacturer's data
Specific Heat	0.634 J/g.K Data Quality: Manufacturer's data

	RELEVANT PROPERTIES FOR USE IN SPACE COMMUNITY

Corrosion/Thermal	Oxidation resistant with retention of useful strength and creep resistance up to 500°C. Strong affinity for H2 (above 130°C), N2 (above 800°C) and O2 (above 700°C), which cause embrittlement.
Stress Corrosion Status	High Resistance to SCC: Table 1 Data Quality: Design Data
Bimetallic Corrosion	Can be connected without any restriction to: Cr, Cu, Brass, Cu-Ni alloys, Al-bronzes, Si-bronzes, Gun metal, P-bronzes, Sn-bronzes, Ag, 300 and 400 series stainless steel, low alloy steel, Au, Pt, C, Rh Can be connected in a non-controlled environment to the above and Ni, Monel, Inconel, Ni-Mo alloys Can be connected in a clean room environment to above and Cd, Al-Cu alloys Needs specific measures: All others Test:ECSS-Q-ST-70C Rev.1 Table 5.1 Data Quality: Design Data
Welding	The alloy may be welded using controlled electron beam or laser welding techniques. Slow welding speeds and low cooling rates are necessary to achieve adequate weld properties.

	SPECIAL RECOMMENDATIONS

Special Recommendations	Alloy possesses poor notch sensitivity characteristics, so considerable care should be taken to avoid the presence of stress raisers. · Methyl alcohol should not be used in the pressure testing of tanks since failure can occur due to stress-corrosion cracking.
Lessons Learned	Welding procedures should always be checked. Argon or helium protection is essential on trailing direction and opposite side