A Comprehensive Guide to Nickel-Based Alloys: Monel K-500 (UNS N05500)
Monel K-500 (UNS N05500/DIN W.Nr. 2.4375/Alloy K-500) is a corrosion-resistant alloy with the largest dosage, the most widely used and excellent comprehensive properties. The alloy has excellent corrosion resistance in hydrofluoric acid and fluorine gas media as well as hot concentrated alkali solutions. Monel K-500 (UNS N05500) is mainly composed of 30% Cu and 63% Ni, and contains a small amount of Fe (1% – 2%), and Monel 400, with added Al and Ti.
Monel K-500 is suitable for operating under the geological mining conditions of high-sulfur and high-wax oil reservoirs. Since this alloy has no plastic-to-brittle transition temperature, it is very suitable for various low-temperature equipment. Monel K-500 alloy not only has excellent mechanical properties such as high strength, corrosion resistance, and non-magnetism, but also has the same characteristics as Monel 400. Can be used as pump shaft material.
Machinability of Monel K-500
The best machinability of this alloy is annealed. It is possible to machine in the aged condition, but the best approach is to get as close to finishing as possible in the annealed condition. Aging and final processing then take place. Very slight dimensional shrinkage occurs during aging. In general, this alloy processes in the annealed condition similarly to austenitic (300 series) stainless steels.
Nickel- and cobalt-based corrosion-, high-temperature and wear-resistant alloys, such as Monel K500, are classified as moderately to difficult to machine, although it should be emphasized that these alloys can be machined at satisfactory rates using conventional production methods. During machining, these alloys work harden rapidly, generate high heat during cutting, weld to the tool surface, and have high resistance to metal removal due to their high shear strength.
Molding of Monel K-500
The alloy has good ductility and is easily formed by standard methods in the annealed condition.
Welding of Monel K-500
All conventional welding techniques can be used with this alloy. However, it is best to weld with the alloy in the annealed condition and then stress-relief anneal the finished weldment. Exposure to temperatures in the age-hardening range (900 F to 1100 F) should be avoided unless a final age-hardening treatment is to be completed.
Thermal processing of Monel K-500
Thermal processing temperature range is 2100 F to 1600 F. Water quench immediately after hot working and do not allow cooling below 1600 F.
Monel K-500 cold working
The alloy has good ductility and can be cold worked by standard methods.
Aging Monel K-500
For annealing or light cold working, the material is age hardened at 1125 F for 16 hours and then furnace cooled to a temperature of 900 F at a rate of 15 F to 25 F per hour. The cooling rate from 900 F to room temperature is not critical. For strictly cold worked materials, aging should be conducted at 1000°F for a minimum of 6 hours, followed by furnace cooling to 25°F at a rate of 900°F to 15°F per hour.
Annealing of Monel K-500
Annealed at 1900 F and water quenched.
Heat treatment Monel K-500
The alloy can be annealed after cold working or precipitation hardened by aging heat treatment.
