UNS N06600 and Alloy 713 both contain high nickel and chromium, but they belong to different families: 600 is a wrought solid-solution alloy whereas 713 is a cast, gamma-prime strengthened superalloy intended for turbine hot section components.
Composition and Family
UNS N06600 is a wrought nickel-chromium alloy with about 72 percent nickel, 14 to 17 percent chromium and 6 to 10 percent iron. Alloy 713 is a cast nickel-based superalloy with roughly 12 to 13 percent chromium, about 6 percent aluminium, molybdenum, titanium, tungsten and other additions.
The aluminium and titanium in 713 form gamma prime precipitates that give it very high strength at high temperature, a mechanism that UNS N06600 does not use.
Manufacturing Route
UNS N06600 bar is produced by hot working and then cold finishing, so it is forged, rolled and machined in the conventional way. Alloy 713 is produced by investment casting, and often by directional solidification or single crystal casting for turbine blades.
Because 713 is a casting alloy, it is normally supplied as cast shapes rather than as wrought round bar, which makes the comparison one of product form as much as of chemistry.
Mechanical Properties at Temperature
UNS N06600 offers moderate strength with excellent ductility and can be used from cryogenic temperatures up to roughly 1100 degrees C in oxidising and carburising atmospheres. Alloy 713 delivers much higher strength in the range of roughly 650 to 1000 degrees C, which is why it is used for turbine blades and vanes.
The trade-off is that 713 is less ductile and less weldable than 600, and it is not suited to the same fabrication methods.
Corrosion and Oxidation Behaviour
UNS N06600 resists caustic solutions, high-purity water, many acids and high-temperature oxidation and carburisation. Alloy 713 relies on its aluminium content to form a protective oxide scale for high-temperature oxidation and hot corrosion resistance.
In chloride or caustic chemical process service, UNS N06600 is generally the appropriate choice, while 713 is optimised for hot gas path conditions.
Applications and Selection
UNS N06600 serves heat treatment fixtures, furnace components, chemical and petrochemical equipment and power plant parts. Alloy 713 is used for turbine blades and vanes, integral wheels and other hot section components in gas turbine engines.
Selection therefore depends on whether the part is a fabricated, wrought component needing corrosion resistance and ductility, or a cast component needing maximum strength in a hot gas stream.
Frequently Asked Questions
Q: Is Alloy 713 available as wrought round bar?
No. Alloy 713 is a cast superalloy normally produced by investment casting rather than as wrought bar.
Q: Why does Alloy 713 have higher high-temperature strength?
Aluminium and titanium additions form gamma prime precipitates that strengthen the alloy at high temperature.
Q: Which alloy is better for chemical process service?
UNS N06600, because it resists caustic solutions, acids and high-temperature oxidation far better than the cast turbine alloy.
Q: What is the main use of Alloy 713?
Turbine blades, vanes and other hot section components in gas turbine engines.
Q: Can the two alloys be welded the same way?
No. UNS N06600 welds readily by conventional processes, while Alloy 713 is much less weldable and is normally used as a casting.
