(1) Ferrous metals are also called steel materials, including industrial pure iron containing more than 90% iron, cast iron containing 2% ~ 4% carbon, carbon steel containing less than 2% carbon, and various structural steels, stainless steels, heat-resistant steels, high-temperature alloys, precision alloys, etc. The generalized ferrous metals also include chromium, manganese and their alloys.
(2) Non-ferrous metals refer to all metals except iron, chromium, manganese and their alloys, which are usually divided into light metals, heavy metals, precious metals, semi-metals, rare metals and rare earth metals. Generally, the strength and hardness of non-ferrous alloys are higher than those of pure metals, with large resistance and small temperature coefficient of resistance. ?
(3) Special metal materials include structural metal materials and functional metal materials with different uses. Among them, there are not only amorphous metal materials obtained by rapid condensation process, but also quasicrystal, microcrystalline and nanocrystalline metal materials. There are also special functional alloys such as stealth, hydrogen resistance, superconductivity, shape memory, wear resistance, vibration reduction and metal matrix composites.
Advantages:
(1) has good heat resistance and is not easy to burn.
? (2) With the change of temperature, the properties have little change.
? (3) High mechanical strength.
? (4) Good durability and not easy to age.
? (5) It is not easy to be damaged and contaminated with dust and dirt.
? (6) Good dimensional stability.