Overview
0Cr27Al7Mo2 is a high-resistance electrical heating alloy with a high content of chromium and aluminum, along with an appropriate amount of molybdenum. These elements give the alloy excellent performance at high temperatures. Below 1250°C, the alloy exhibits high oxidation resistance and thermal strength, forming a dense Al2O3 oxide layer on its surface. It has a high electrical resistivity and a low temperature coefficient, making it suitable for use in high-temperature heating elements.
The mechanical properties of Cr27Al7Mo2 at room temperature are relatively poor, with low plasticity and poor cold stamping and welding performance. However, in an annealed state, it has a ferrite microstructure. This alloy is primarily used for heating elements in heat treatment furnaces, particularly in continuous furnaces, such as those used for stainless steel solution annealing.
Limiting Chemical Composition, %
Chromium..............................................................................................................................................................................26.5--27.8
Aluminum..................................................................................................................................................................................5.0--7.0
Carbon.....................................................................................................................................................................................0.05 Max.
Nickel........................................................................................................................................................................................0.60 Max.
Silicon.......................................................................................................................................................................................0.40 Max.
Manganese.............................................................................................................................................................................0.20 Max.
Phosphorus...........................................................................................................................................................................0.025 Max.
Sulfur.......................................................................................................................................................................................0.025 Max.
Molybdenum........................................................................................................................................................................1.80--2.20
Iron...............................................................................................................................................................................................Balance.
Physical Constants
Density | 7.1 g/cm³ |
Resistivity | 1.53 μΩ·m |
Tensile strength | ≥680 Mpa |
Bending frequency | ＞5 |
Melting piont | 1500℃ |
Elongation | ＞10% |
Characteristic
High resistivity: suitable for the manufacture of electric heating elements.
Excellent oxidation resistance: It has high oxidation resistance and thermal strength below 1250℃, and the surface will form an Al2O3 oxide film.
Low temperature coefficient: Resistance value varies little with temperature.
Ferritic structure: the alloy is a ferritic structure after annealing, but the structure is unstable during use, and 475℃ is a brittle temperature zone.
Application
Electric heating element: mainly used for heat treatment furnace with temperature below 1250℃, especially suitable for continuous furnace, such as stainless steel solid solution furnace.
