Four Major Properties of Metallic Materials

Ⅰ. Mechanical Properties

The ability of a metal to resist deformation and fracture when it is subjected to external forces under certain temperature conditions is called the mechanical properties of the metal material. 
1.Strength:

This represents the maximum ability of a material to resist deformation and damage under the action of external forces, and can be divided into tensile strength limit, bending strength limit, compressive strength limit, etc. Since metal materials follow certain rules from deformation to destruction under the action of external force, tensile testing is usually used for measurement. That is, the metal materials are made into specimens of certain specifications and stretched on a tensile testing machine.

2.Plasticity:

The maximum ability of a metal material to produce permanent deformation without destruction under the action of external force is called plasticity, which is usually expressed by the sample gauge length elongation δ (%) and the sample section shrinkage ψ (%) during the tensile test. 

3.Toughness:

The ability of a metallic material to resist damage under impact load is called toughness. The impact test is usually used, that is, when a metal sample of a certain size and shape is broken under an impact load on a specified type of impact testing machine, the impact energy consumed per unit cross-sectional area on the fracture surface is used to characterize the toughness of the material.

Ⅱ. Chemical Properties

The property of metals to cause chemical reactions with other substances is called the chemical properties of metals. In practical applications, the main considerations are the corrosion resistance and oxidation resistance of metals (also called oxidation resistance, which specifically refers to the resistance or stability of metals to oxidation at high temperatures), as well as the relationship between different metals, and the relationship between metals and metals. The effects of compounds formed between non-metals on mechanical properties, etc. Among the chemical properties of metals, corrosion resistance is of great significance to the corrosion fatigue damage of metals.

Ⅲ. Physical Properties

1.Density (specific gravity): 

ρ=P/V in grams/cubic centimeter or ton/cubic meter, where P is the weight and V is the volume. In practical applications, in addition to calculating the weight of metal parts based on density, it is important to consider the specific strength of the metal (the ratio of strength σb to density ρ) to help material selection, as well as the acoustic impedance in acoustic testing related to non-destructive testing (The product of density ρ and sound speed C) and in radiation detection, materials with different densities have different absorption capabilities for radiation energy, etc.

2.Melting Point: 

The temperature at which metal changes from solid to liquid. It has a direct impact on the smelting and thermal processing of metal materials, and has a great relationship with the high-temperature properties of the material.

3.Thermal Expansion:

The phenomenon that the volume of a material changes (expanses or contracts) as the temperature changes is called thermal expansion. It is often measured by the linear expansion coefficient, which is the ratio of the increase or decrease in the length of the material when the temperature changes by 1°C to its length at 0°C. 

4.Magnetism:

The property that can attracts ferromagnetic objects is called magnetism, which is reflected in parameters such as magnetic permeability, hysteresis loss, residual magnetic induction intensity, and coercive force. Thus, metal materials can be divided into paramagnetic and diamagnetic, soft magnetic and hard magnetic materials. 

5.Electrical Properties:

Electrical properties mainly consider its conductivity, which has an impact on its resistivity and eddy current loss in electromagnetic non-destructive testing.

Ⅳ. Processing Properties

The adaptability of metal to various processing methods is called processing properties, which mainly include the following four aspects:

1.Cutting Performance: reflects the difficulty of cutting metal materials with cutting tools (such as turning, milling, planing, grinding, etc.).

2.Forgeability: reflects the difficulty of forming metal materials during pressure processing, such as the plasticity of the material when it is heated to a certain temperature (shown as the magnitude of plastic deformation resistance), the temperature range that allows hot pressure processing, and the expansion and contraction characteristics, as well as the limits of critical deformation related to micro-structure and mechanical properties, metal fluidity and thermal conductivity during thermal deformation, etc.

3.Castability: reflects the difficulty of melting and casting a metal material into a casting, which is manifested by the fluidity, oxidation, melting point in the molten state, the uniformity and density of the microstructure of the casting, and the cold shrinkage rate, etc. 

4.Weldability: reflects the difficulty of rapid local heating of metal materials to quickly melt or semi-melt the joint parts (pressure is required), so that the joint parts can be firmly bonded together to form a whole. Weldability is manifested by the melting point, gas gettering during melting, oxidation, thermal conductivity, thermal expansion and contraction characteristics, plasticity, correlation with the microstructure of the joint and nearby materials, and the impact on mechanical properties.

The above briefly sums up the four major properties of metallic materials. Please feel free to reach us if you have any questions regarding this blog, or if you are looking for the right steel products for your business! 

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