Jiangyin MITOO precise is a company who mainly manufacture and sell the Steel forgings .Including Ring forgings , and Free forging products , such as the shafts, flanges . The material including : carbon steel , low alloy steel , and stainless steel . Invar 36, also known as feni36, is an iron nickel alloy with a low coefficient of expansion only in a fairly narrow temperature range. The coefficient of expansion from low temperature to about 260 ℃ is low. Invar 36 has good corrosion resistance in normal temperature and dry air. But in humid air, it may corrode.