Overview of 4J36 expansion alloy: The Curie point of 4J36 expansion alloy is about 230℃. Below this temperature, the alloy is ferromagnetic and has a very low expansion coefficient. Above this temperature, the alloy is nonmagnetic and its expansion coefficient increases. The alloy is mainly used to manufacture parts with approximately constant dimensions in the temperature range, and is widely used in radio industry, precision instruments, meters and other industries. 4J36 alloy is a typical low expansion alloy, which has been used in aviation factories for a long time and its performance is stable. In use, the heat treatment process and processing technology should be strictly controlled to ensure the stability of the material.
4J36 Similar brands: Fe-Ni36, W.Nr. 1.39 12, Ni36, X 1 Nicomocu, N 25-20-7, UNSK9360 1.
4J36 Chemical composition:
Nickel, nickel, chromium, iron, carbon, manganese, silicon, cobalt and phosphorus
35 0.30
37 0.2 allowance 0.03 0.60 0.2 0.5 0.02 0.0 1
4J36 Density: ρ=8. 1g/cm3
The heat treatment of 4J36 parts can be divided into stress relief annealing, intermediate annealing and stabilization treatment.
1. stress relief annealing in order to eliminate the residual stress after machining, stress relief annealing should be carried out: 530 ~ 550℃, heat preservation 1 ~ 2h, and cooling with the furnace.
2. Intermediate annealing is to eliminate the work hardening phenomenon of alloy during cold rolling, cold drawing and cold stamping, so as to facilitate continuous processing. Heat the workpiece to 830 ~ 880℃, keep the temperature for 30 minutes, and cool it with furnace or air.
3. The stabilization treatment is to obtain the treatment with low expansion coefficient and stable performance. Generally, three-stage treatment is adopted.
Homogenization: during the heating process, the impurities in the alloy are fully dissolved and the alloy elements tend to be uniform. Under the protective atmosphere, the workpiece is heated to 830℃, kept for 20min ~ 65438+/-0h, and quenched.
Tempering: The stress caused by quenching can be partially eliminated during tempering. The workpiece was heated to 3 15℃, kept at 1 ~ 4h, and cooled with the furnace.
Stabilization aging: make the alloy size stable. The workpiece was heated to 95℃ and kept for 48 hours. For high-precision parts after cold working or mechanical processing, when it is not suitable for high-temperature treatment, it can be used for stress stabilization treatment: the workpiece is heated to 3 15 ~ 370℃, 1 ~ 4h. This alloy cannot be hardened by heat treatment.
4J36 Surface treatment process: The surface treatment can be sandblasting, polishing or pickling. The alloy can be washed with 25% hydrochloric acid solution at 70℃ to remove scale. At 4000 A/m, the residual magnetic induction intensity Br=0.6T and the coercivity HC = 48a/ m. ..