Basic knowledge of metal materials

Basic knowledge of metal materials

The properties of metal materials are generally divided into two categories: technological properties and operational properties. The so-called technological performance refers to the performance of metal materials under certain cold/hot working conditions during machining and manufacturing of mechanical parts.

The so-called service performance refers to the performance of metal materials in the service conditions of mechanical parts, including mechanical properties, physical properties, chemical properties and so on. The performance of metal materials determines its range of use and service life. In the machinery manufacturing industry, the general mechanical parts are used in normal temperature, atmospheric pressure and non-strongly corrosive media, and in the process of use, the mechanical parts will bear different loads. The resistance of metallic materials to failure under load is called mechanical property. The so-called technological performance refers to the performance of metal materials under certain cold/hot working conditions during machining and manufacturing of mechanical parts. The technological performance of metal materials determines its adaptability to forming in the manufacturing process. Due to different processing conditions, the required process performance is different, such as casting performance, weldability, malleability, heat treatment performance, machining performance, etc.

1. The ability of metal materials to obtain qualified castings by casting method is called casting property. The casting property includes fluidity, shrinkage and segregation tendency. Fluidity refers to the ability of liquid metal to fill the mold. The better the fluidity, the easier it is to cast thin and delicate castings. Shrinkage refers to the degree of volume shrinkage of casting during solidification. The smaller the shrinkage, the smaller the deformation of casting during solidification. Segregation refers to the chemical composition is not uniform, the more serious segregation, the more uneven the performance of each part of the casting, the less reliability of the casting.

2 Machinability of metal materials machinability refers to the ability of metal to accept cutting, but also refers to the degree of difficulty of metal through machining to become a required workpiece. The machinability of a metal can usually be evaluated by the roughness of the working surface, cutting speed and tool wear after cutting.

3 Weldability Weldability refers to the performance of a metal in a specific structure and process conditions to obtain the desired quality of welded joints by common welding methods. It includes two aspects: one is the combination of performance, that is, under certain welding process conditions, a certain metal to form the sensitivity of welding defects, the other is the use of performance, that is, under certain welding process conditions, a certain metal welded joint applicability to the use of requirements. Weldability is generally judged according to the crack sensitivity and the mechanical properties of the weld zone. Click on the following links to learn more about welding! A picture to understand the welding of metal materials (above) - welding foundation A picture to understand the welding of metal materials (below) - welding material model welding material selection table, do not miss, must collect! The most advanced welding technology summarizes the new welding technology, the prospect is unlimited

4. Malleability Malleability is the property that the material will change shape without cracking when subjected to machining processes such as hammer forging, rolling, drawing and extrusion. It is actually a manifestation of metal plasticity. The higher the plasticity of metal materials, the smaller the deformation resistance and the better the malleability. The malleability mainly depends on the chemical composition, microstructure, deformation temperature, deformation velocity and stress state of the metal.

5 Stamping property Stamping property refers to the metal through stamping deformation without cracks and other defects. Many metal products are manufactured by stamping process, such as automobile shell, enamel products blank and POTS, POTS, Meng, POTS and other daily necessities. In order to ensure the quality of the products and the smooth progress of the process, the metal plate and belt used for stamping must have qualified stamping performance.

Top forging property refers to the ability of metal materials to withstand the top forging deformation of rivet, seal, etc. The top forging property of metals is determined by the top forging test.

7 Cold bending metal materials at room temperature can withstand bending without cracking performance, known as cold bending. The bending degree that can be borne before the crack appears (the bending degree is generally expressed by the ratio of bending Angle α (outer Angle) or bending core diameter d to material thickness a, the larger the a or d/a is, the better the cold bending performance of the material.

8 Heat treatment technology Heat treatment refers to a process operation in which the internal structure of the metal or alloy is changed through certain heating, insulation and cooling methods in the solid state to obtain the required properties. Heat treatment manufacturability refers to the ability of metal to change its structure and properties after heat treatment, including hardenability, hardenability, tempering brittleness, etc.