CNC Knowledge: Four processes that strengthen metals

01 Solid solid

definition

The alloy element is solid-soluble in substrate metal to a certain degree of distortion of the network, which increases the force of the alloy.

principle

Soluble atoms in solid-soluble solids cause network distortion. This phenomenon which improves the strengthening of metals by dissolving a soluble element to form a soluble solid body is called soluble solid strengthening. When the concentration of soluble atoms is appropriate, the resistance and hardness of the material can be improved, while its tenacity and its plasticity have decreased.

Influential factors

The higher the atomic score of the solution atom, the higher the reinforcement effect, especially when the atomic score is low, the reinforcement effect is more significant. The more the size of the atomic atom of the solution atom and matrix metal, the greater the reinforcement effect.

The GAP -type soluble atom compared to the replacement atom by a large soluble solid strengthening effect, and because the distortion of the point matrix of the space atom in the cubic crystals of the body is not proposed , its reinforcement effect is higher than facial cubic crystal; But atomic atoms in space The solid solution is limited, so the actual strengthening effect is limited.

The more the number of electrons in the price of soluble atoms and matrix metals, the more obvious the effect of soluble soluble strengthening, that is to say that the elasticity limit of the solid-Soluble body increases with the Increase in electronic concentration of the concentration of electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of Electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration of the electronic concentration electronic concentration of the body price.

The degree of strengthening the solid solution

It mainly depends on the following factors:

(1) Dimension between the atom of the substrate and the solution atom. The greater the difference in size, the greater the interference of the primitive crystalline structure, the more difficult it is to slip.

(2) The amount of alloy elements. The more alloy elements are added, the higher the effect of strengthening. If you add too much or too many small atoms, it will exceed the solution. This implies another reinforcement mechanism, which is decentralized.

(3) The atoms of atoms of the meaponic solution have a solid and soluble solid strengthening effect.

(4) The more the number of electrons in the price of soluble atoms and matrix metals is greater, the greater the soluble solid strengthening effect.

Effect

The strength of success, stretching force and hardness are stronger than pure metals;

In most cases, ductility is lower than that of pure metal;

The conductivity is much lower than that of pure metals;

Anti-screen changes, or high loss at high temperature, can be improved by soluble solid strengthening.

02 Treatment of hardening

definition

With the increase in cold deformation, the resistance and hardness of the metal materials have increased, but plasticity and tenacity have decreased.

Brief introduction

The metal material increases resistance and hardness when plastic deformation below the crystallization temperature, while plasticity and tenacity are reduced. Also known as cold harvesting. The cause is that when the metal deforms, the grains are slippery, and the incorrect tangles occur, which makes the grains, crushed and fibrosis drawn, and the remains of constraint inside the metal. The degree of treatment sclerosis is generally used to indicate treatment sclerosis with the ratio of micro-duretity and the depth of the surface layer before treatment.

Explanation from the point of view of bad theory

(1) incoherent between the bits and the incorporation of cutting levels hinders the misunderstanding of the position;

(2) The reaction occurs in poor position, and the fixed fixing bits are implicitly hampered by the bits;

(3) The proliferation occurs in poor position, and the increase in the density of the bit increasing the problem of movement movement has increased further.

harm

The treatment of sclerosis leads to difficulties in treating metallic parts later. If the cold steel plate will be launched and difficult to drive, it is necessary to organize an intermediate reception in the processing process during treatment and to eliminate the hardening of heating treatment. Another example is that the surface layer of the part is crisp and hard in the cutting process, thus accelerating the wear of the tool and the increase in the cutting force.

advantage

It can improve strength, hardness and resistance to metal abrasion, in particular for pure metals and certain alloys that cannot increase strength with thermal treatment methods. Such as high intensity steel wires-cold location and cold roller springs, that is to say using the cold treatment deformation to improve its resistance and its elasticity limit. Another example is that tanks, tractors, tractors, jaw panels and railway railways also use the hardening of treatment to improve their hardness and wear resistance.

The role in mechanical engineering

After cold traction, rolling and spraying (reinforcement of the surface), it can considerably improve the resistance of the surface of materials, parts and metallic components;

After parts of parts, the local constraint in certain parts often exceeds the limit of resolution of materials, causing plastic deformation.

When the metallic parts or components are dush, plastic deformation is accompanied by a reinforcement, so that the deformation is transferred to the surrounding hardening part. After repeated alternating effects, cross sectional deformation and uniform cold pumping parts will be obtained;

It can improve steel cutting performance with low carbon content and make the haste easily separated. However, the treatment of sclerosis also causes difficulties in the subsequent treatment of metallic parts. For example, the cold traction threads, because the hardening of the treatment made of additional energy consumption and even the broken, it must therefore recover in the middle, eliminating the hardening of the treatment and then pulling. Another example is to increase the cutting force when cutting the part of the part in the cutting process, adding the cutting force during cutting and accelerating the wear of the tool.

03 Strengthening fine crystals

definition

The method of improving the mechanical performance of the metal material by refining grains is called strengthening of fine and refined grains industrially to improve the resistance of the material.

principle

Generally, metal is a polycrystal made up of many grains. Experiences show that fine crystalline metals at room temperature have resistance, hardness, plasticity and higher tenacity than gross crystalline metals. Indeed, plastic deformation of fine grains can be dispersed in more grains. The more it is not conducive to the expansion of cracks. Consequently, the industry will be called the strengthening of fine crystals by refining cereal grains to improve the resistance of the material.

Effect

The smaller the grains, the lower the bad number (N) in the middle of the bad together, the smaller the concentration of stress, and the lower the resistance of the material; Eassembled, the lower the average of the grain (D), the higher the elasticity of the material. >>>>

Refer

Increase compared to cooling;

Humidity;

Vibrations and stir;

Cold deformation metals can be refined by controlling the deformation of the deformation.

04 Second phase strengthening

definition

Compared to unique phase alloys, in addition to the substrate, there is a second phase. When the second phase is uniformly distributed in the matrix phase with small or diffuse particles, it will produce a significant strengthening. This strengthening is called the second improvement in the phases.

Classification

For bad movement, the second phase of the alloy contains the following two situations: (1) The effect of improving non -reformable particles (bypassing the mechanism). (2) Strengthening of deformation particles (cutting mechanism). The improved and precipitated improvement of SAN belongs to the special situation of the second strengthening of the phase. >>>>

Effect

The main reason for strengthening the second phase is the interaction between them and poor position, which hinders bad movement and improved resistance to the deformation of the alloy.

To summarize

The most important thing in the factors that affect intensity is the ingredients, the organizational structure and the status of surface of the material itself; It will show different forces; .

The way to improve metal materials is not two. The intensity of the crystalline beard is known as the theoretical value. Unfortunately, when the diameter of jingxu is important, the intensity will decrease sharply. Another strengthening path is to introduce a large quantity of crystal crystal defects, such as incorrection, punctual defects, heterogeneous atoms, crystalline worlds, highly diffused mass points or inequality (such as collection partial), etc. Obviously improve the strength of the strength of metal strength. It turns out that it is the most effective way to improve the strength of metal. For engineering materials, it is generally a question of obtaining good complete performance thanks to complete reinforcement effects.