In real world, Heat Treatment is not strange and not abstract to us, because many things can not go without Heat Treatment. And here, we will talk about heat treatment of metal material.
We know that there is two ways to change the property of steel:
1. Adjust the chemical components of steel, add alloy element, and develop new alloy material.
2. To apply heat treatment.
What is the advantage for applying heat treatment to steel?
It can exert the potential of material, improve the quality of mechanical products, prolong the service life of steel and save metal material, so the heat treatment is: to heat up metal in normal condition, preserve temperature and through different cooling measure, to change the internal structure of metal, and achieve the necessary operation technique. This heat treatment can change all properties of steel, so lets talk about the property knowledge and some common senses of metal materials:
The property of metal material can be separated into two kinds:
1. Apply performance: the property that metal materials shows during use. For example: mechanical performance, physical performance, anti-oxygen performance, oxidation resisting performance, corrosion resistance performance and other chemical and physical performances.
2. Technical performance: the property that metal material shows during manufacturing. For example: die-casting performance, pressing processing(plastic forming) performance, welding performance and welding performance etc.
The mechanical performances of metal materials are: intensity, plasticity, rigidity, impact performance, fatigue intensity and etc.
1. Intensity: intensity is the resistivity of metal material against distortion or rupture caused by static electricity.
2. Plasticity: The properties of a material that allow it to be shaped and to retain its shape. Deformation that can not retain to its original shape after the outside force remove is called plastic deformation.
3. Rigidity: the ability to resist the pressing of other hard objects. Or materials resistance to partial plastic deformation.
4. Impact performance: impact tenacity is the ability that materials resist impact and no crack.
5. Fatigue intensity: under alternating load, which both intensity and direction always change, the ability value which lower than the yield limit in the static load tensile test is called metal fatigue. (note: s is the code name of yield limit.).
6. Technical performances: ductility, forgeability, machinability, solderability and castability.
Metal material usually can be separated into ferrous metal and non-ferrous metal. Steel, iron, chrome and ,manganese are ferrous metals, the others are non-ferrous metals.
Carbon steel is iron carbon alloy with lower than 2.06% carbon content.
Usually steel carbon content0.25% is call mild steel, carbon content between 0.25%0.6% is called medium steel, and between 0.6%1.4% is called high carbon steel.
Besides contain iron and carbon, steel also contain silicon(Si), manganese(Mn), sulfur (S), phosphor (P) and other impurities.
|
TECHNIC FILE
