2024年3月21日发(作者：联想哪一款笔记本电脑性价比高)

金属材料（Metallic materials）

Process properties of metal materials

Casting properties

The ability of metal materials to cast and obtain good castings

is called casting properties. Measured by fluidity, shrinkage,

and segregation.

The flow of molten metal flow capacity - called liquidity. The

liquid metal is easy to fill the mold, and gets the casting with

full shape, precise size and clear outline.

The shrinkage - casting during solidification and cooling

process, the volume and size to reduce the phenomenon known as

shrinkage. Shrinkage not only affects size, but also causes

shrinkage, porosity, internal stress, deformation and cracking

of castings.

The segregation of metal solidification, the phenomenon of

uneven casting or ingot of chemical composition and

organization called segregation. Segregation will make the

mechanical properties of each part of the casting vary greatly,

and reduce the quality of the casting.

Forging performance

The ability to form a metal material by forging is called

malleability. The better the plasticity, the smaller the

deformation resistance, the better the metal forging.

Weldability

The adaptability of metal materials to welding is called

weldability. In the mechanical industry, the main object of

welding is steel. Carbon quality fraction is a major factor in

welding quality. The higher the carbon mass fraction and the

alloy element mass fraction, the worse the welding performance.

Cutting performance

Machinability is generally represented by the surface quality

after cutting (as measured by surface roughness) and tool life.

Metals with good hardness (170HBS to 230HBS) and sufficient

brittleness have good cutting properties. The machinability of

the steel can be improved by changing the chemical composition

of the steel (a small amount of lead and Lin Yuansu) and proper

heat treatment (low carbon steel normalizing, high carbon steel

spheroidizing annealing).

Heat treatment process performance

The heat treatment process of steel mainly depends on its

hardenability, that is, the ability of steel to undergo

quenching. Alloy steels with alloy elements such as Mn, Cr and

Ni have better hardenability, and the hardenability of carbon

steels is poor.

Mechanical properties of metallic materials

The quality of the material is related to the service life of

the equipment and the development of the whole national economy,