Nickel 200 (UNS NO2200) is commercially pure (99.6%) wrought nickel. It has excellent mechanical properties and is highly resistant in myriad corrosive environments. Other useful features include:
- magnetic and magnetostrictive properties
- high thermal and electrical conductivities
- low gas content and low vapor pressure.
It is Nickel 200’s corrosion resistance that makes it particularly useful for maintaining product purity in the handling of:
- synthetic fibers
- caustic alkalies
structural applications where resistance to corrosion is a prime consideration.
Other applications include:
- chemical shipping drums
- electrical and electronic parts
- aerospace and missile components
- rocket motor cases
Nickel 200 works best at temperatures below 600°F (315°C). It is not recommended for higher temperatures. Nickel 201 is preferred for anything over 600°F (315°C) and up to 1250°F (677°C).
Both Nickel 200 and 201 are approved for construction of pressure vessels and components under ASME Boiler and Pressure Vessel Code Section VIII, Division 1. Nickel 200 can be used to reduce the development of passive oxide films in highly oxidative media. It offers outstanding resistance to caustics and is highly protective In all environments.
This Nickel Alloy may be annealed over a wide range of temperatures above its recrystallization temperature. For heavily cold worked material, the temperature may be as low as 1100° to 1200°F (595° to 650°C), but from a practical viewpoint, the range is usually about 1300 to 1700°F (705° to 925°C). Grain growth is rather rapid in Nickel 200 at elevated temperatures owing to the absence of a number of residual elements and secondary phases that tend to inhibit grain growth in more complex alloys. At higher temperatures, time at temperature must be carefully watched in order to exercise control over grain size.
Batch annealing in the box, retort, or open furnaces is usually performed in the range of 1300° to 1500°F (705° to 815°C) for about 30 minutes to 3 hours, depending on the cross-section and amount of contained cold work. Because of its high thermal conductivity, the heating rate will be relatively rapid. The cooling rate is not critical, and quenching is not necessary except as a means to shorten the heat-treating cycle or to partially reduce any surface oxide developed during heating or cooling in an oxidizing atmosphere.