Monel 400 is a typical Nickel-Copper alloy with high strength and excellent corrosion resistance to seawater, hydrofluoric acid, sulfuric acid, and alkalies. They are widely used for marine engineering, chemical and petrochemical industry, and power plant piping, etc. However, due to its low coefficients of thermal conductivity & linear thermal expansion and high susceptibility to hot cracking, failure may occur during the welding of Monel 400 alloys. The study on Monel 400’s mechanical properties at elevated temperatures is necessary.

Monel 400 Specimens Preparation

The testing specimens shall be hot-rolled Monel 400 rods manufactured to ASTM B164 UNS N04400, under annealed condition. Specification: Φ6 x 120 mm, 6 pieces. Its actual chemical composition is attained by PMI testing(all in weight %): C-0.12, Si-0.10, Mn-1.04, Ni-65.8, Cr-0.085, Fe-1.15, Cu-31.8, Ti-0.045, Co: 0.012, Mo: 0.014.

Testing Apparatus

The testing machine is Gleeble 1500D thermal-machanical simulator. The test was conducted in Metals-Piping’s cooperative lab: Inner Mongolia University of Science & Technology(IMUST).

High-Temperature Tension Test Procedures

The Monel 400 specimens shall be tested at temperatures 600°C, 700°C, 800°C, 900°C, 1000°C, and 1100°C, respectively. The heating rate shall be 10°C/s while the cooling rate shall be at 3°C/s. The strain rate imposed on each specimen shall be 10^-3/s. The tensile process shall be conducted in vacuum environment until the specimen is broken. Record the values of stress, strain, tensile strength, yield strength, elongation and area of reduction at each testing temperature. Take scanning electron microscope (SEM) inspection on the fracture surface of the specimen. The test results and further analysis are listed below:

• Mechanical Properties of Monel 400 alloy at elevated temperatures.
• Analysis on ductility and fracture of Monel 400 specimens.