Monel K500 Monel alloy material and process introduction
Monel K500 material introduction
Monel K500 alloy is a Ni-Cu-based alloy. By adding a small amount of Al and Ti elements, the Ni3 (Al, Ti) phase is precipitated. It retains the excellent corrosion resistance of Monel 400 alloy and at the same time has high strength due to precipitation strengthening. , is widely used in petroleum, chemical industry, atomic energy and other industrial fields.
By adding Al, Ti and other elements to the Ni-Cu matrix, a malleable precipitation hardening Monel K500 alloy is produced. This alloy shows excellent corrosion resistance in seawater, acid, alkali and salt environments, and is compatible with Ni-Cr-based alloys and precipitation-hardened low-alloy steels have room temperature strength and hardness comparable to that of Ni-Cr-based alloys. They are tough and plastic even at low temperatures of -25K and can maintain their strength at temperatures as high as 920K. The alloys are particularly suitable for making field oil production electricity. The pump shaft of a submersible pump.
Monel K500 chemical composition
Effect of trace element addition on high temperature plasticity of Monel K500
(1) Adding a trace amount of Mg to Monel K-500 alloy can increase the grain boundary bonding force and improve high-temperature plasticity.
(2) The high-temperature plasticity of the experimental alloy with trace amounts of Mg, Cr and Co added at the same time is significantly improved, and it exhibits a certain degree of superplasticity. The strain rate sensitivity index m at 1010°C is 0.32, and the maximum elongation is 240%.
(3) The theoretical calculation of the fracture work of impurity elements segregated at grain boundaries shows that Mg, Cr and Co have the effect of improving the grain boundary bonding force of Ni-Cu alloy, and therefore can improve the high-temperature plasticity of Monel K-500 alloy.
(4) The deformation activation energy is low during superplastic deformation, and the process may be controlled by diffusion.
Monel K500 aging cracking prevention
(1) After large cold deformation, MonelK-500 alloy has a strong tendency to age cracking. Cracks initiate on the surface and propagate toward the center, with both transgranular and intergranular forms.
(2) The residual stress caused by cold working, the superposition of aging thermal stress, and the preferential embrittlement of the surface layer in the early stages of aging are the main reasons for age cracking of MonelK500 alloy.
(3) Mechanical straightening after cold working is beneficial to the relaxation and adjustment of residual stress caused by cold working, and can effectively prevent the aging cracking tendency of Monel K-500 alloy.
