ATI K-500™ Alloy (UNS N05500) is an age-hardenable nickel-copper alloy characterized by the good general corrosion resistance of ATI 400 Alloy with the added advantage of increased strength and hardness. The alloy maintains good strength up to 1,200°F (648°C) and is strong and ductile to temperatures as low as -423°F (-217°C). As with ATI 400 Alloy, the alloy has excellent resistance to flowing brines, brackish water, and seawater. The alloy also has low magnetic permeability to -210°F (-99°C).

This alloy is commonly used in the oil and gas, and the marine industries. Applications for ATI K-500™ alloy include pumps and drive shafts, impellers, valve components, springs, fasteners, oil well packers, and subsurface safety valves. Standard mill forms for ATI K-500™ alloy include bar, tube, shapes, and forgings.