The most complete knowledge of metal materials you haven't seen
Metal materials are usually divided into ferrous metals, non-ferrous metals and special metal materials.
(1) Ferrous metals are also called steel materials, including industrial pure iron with more than 90% iron, cast iron with 2% to 4% carbon, carbon steel with less than 2% carbon, and structural steel, stainless steel, Heat-resistant steel, high-temperature alloy, stainless steel, precision alloy, etc. Ferrous metals in a broad sense also include chromium, manganese and their alloys.
(2) Non-ferrous metals refer to all metals and their alloys except iron, chromium, and manganese, which are usually divided into light metals, heavy metals, precious metals, semi-metals, rare metals and rare earth metals. The strength and hardness of non-ferrous alloys are generally higher than that of pure metals, and the resistance is large and the temperature coefficient of resistance is small.
(3) Special metal materials include structural metal materials and functional metal materials for different purposes. Among them, there are amorphous metal materials obtained by rapid condensation process, as well as quasicrystalline, microcrystalline, nanocrystalline metal materials, etc.; there are also special functional alloys such as stealth, hydrogen resistance, superconductivity, shape memory, wear resistance, vibration damping, etc. And metal matrix composite materials.
Generally divided into two categories: process performance and use performance. The so-called process performance refers to the performance of metal materials under the specified cold and hot processing conditions in the processing and manufacturing process of mechanical parts. The process performance of metal materials determines its adaptability in the manufacturing process. Due to different processing conditions, the required process performance is also different, such as casting performance, weldability, forgeability, heat treatment performance, machinability, etc.
The so-called use performance refers to the performance of the metal material under the conditions of use of the mechanical parts, which includes mechanical properties, physical properties, chemical properties, etc. The performance of a metal material determines its range of use and service life. In the machinery manufacturing industry, general mechanical parts are used in normal temperature, normal pressure and very strong corrosive media, and each mechanical part will bear different loads during use. The performance of metal materials to resist damage under load is called mechanical properties (also known as mechanical properties in the past). The mechanical properties of metal materials are the main basis for the design and material selection of parts. The nature of the applied load is different (such as tension, compression, torsion, impact, cyclic load, etc.), and the required mechanical properties of the metal material will also be different. Commonly used mechanical properties include: strength, plasticity, hardness, impact toughness, multiple impact resistance and fatigue limit.
Properties of metal materials
The properties of metal materials determine the scope of application of the material and the rationality of its application. The properties of metal materials are mainly divided into four aspects, namely: mechanical properties, chemical properties, physical properties, and process properties.
The adaptability of metals to various processing methods is called process performance. (1) Machinability; (2) Forgeability; (3) Castability; (4) Weldability.