What are the main factors affecting the wear resistance of materials

Product introduction

What are the main factors that influence the wear resistance of materials? In everyday life, some materials are not suitable because of their poor wear resistance. Here, Shanghai Qianshi tells you that the wear resistance of materials is affected by many factors. What are the specific factors? Let\'s find out together!

What are the main factors that influence the wear resistance of materials? According to Shanghai Qianshi, the main factors affecting the wear resistance of materials are:

1. Hardness

The wear resistance of metal materials can be determined by measuring the hardness of materials. This is mainly because the hardness of the material reflects the ability of the material to resist pressing into the surface. The depth of the material with high hardness in the surface of itthe material presses is shallow, and the volume of abrasive debris generated by cutting is small, that is, the wear is small and the wear resistance is high. Therefore, the metal structure that leads to an increase in the hardness of the material generally also improves the wear resistance of the material. Due to the differences in material composition and structure, the material structure may not be suitable for a specific wear condition, and the hardness cannot be a sufficient basis for comparing the wear resistance of materials.

Second, crystal structure and mutual solubility of crystals

Densely packed hexagonal lattice metal materials, even if the friction surface is very clean, its friction is a factor is still 0.2 to 0.4, and the wear is also low. Cobalt belongs to this typical material, so cobalt can be used as an important component of wear-resistant alloys mwith a high hardness. A pair of metal friction pairs with poor mutual solubility in metallurgy can obtain a lower coefficient of friction and wear rate. If the material that forms a friction pair with steel has very little iron solubility, or if the material is an intermetallic compound, the wear resistance of the surface of the friction pair is better.

Third, temperature

Temperature mainly changes the resistance of metal materials through the influence of hardness, crystal structure transformation, mutual solubility and increased oxidation rate. abrasive. The hardness of metals generally decreases with increasing temperature, so as the temperature increases, the rate of wear increases. Some friction parts (such as high temperature bearings, blades) require materials with high thermohardness. The material must contain alloying elements such as cobalt, chromium, tungstename and molybdenum. Friction pair miscibility can be viewed as a function of temperature. When the temperature rises, the material dissolves easily, which affects the wear rate of the material. In addition, the increase in temperature provokes the increase in oxidation rate and has a significant effect on the types of oxides formed, so it also plays an important role in the friction and wear properties of metals.

Four, plasticity and toughness

High plasticity and toughness indicate that the material can absorb a lot of energy, cracks are not easy to form and expand , and the material has a great ability to withstand repeated deformation. It is not easy to form fatigue spall, that is, it has good wear resistance. Tests have shown that the wear resistance of different materials with the same hardness is a difference. ESimilarly, different materials with the same toughness have different wear resistance. For example, if you compare the quenched sample with the quenched + tempered sample, the hardness may be the same, but the wear resistance is different due to the difference in toughness. The essence is that the wear resistance is different due to the difference in microstructure. But if Te microstructure of wear-resistant materials is the same, the wear resistance can be measured by hardness.

5. Strength

During the wear process, the metal matrix has high strength, which can provide good support for the wear-resistant hard phase and fully play the wear-resistant hard phase. Compared with the ability to withstand wear, the wear-resistant material shows excellent wear resistance. Under the same hardness, high strength wear-resistant materials have better wear resistance.

Six, inclusions and other metallurgical defects

Metallurgical defects such as non-plastic inclusions in steel have a serious impact on fatigue wear. Like nitrides, oxides, silicates and other angular particles in steel, during the stress process, their deformation cannot be coordinated with the matrix to form voids, which are a source of stress concentration, and cracks appear and expand under the influence of alternating locks of hair, leading to the early appearance of fatigue wear. Therefore, it is very important to choose steel with less harmful inclusions (such as refined steel commonly used in bearings) to improve the ability of friction pairs to resist fatigue wear. In some cases, the anti-fatigue wear ability of cast iron is better than that of steel, because the micro-cracks in steel have a certain direction under the influence of friction force, and it is easy to enter oil and expand;while the matrix structure of cast iron contains graphite, cracked graphite develops and has no directionality, and lubricating oil is not easy to penetrate into the cracks.

Seventh, surface roughness

Under the condition of constant contact stress, the smaller the surface roughness value, the higher the fatigue wear resistance. When the surface roughness value is small to a certain value, the influence of fatigue wear resistance will be reduced. Such as rolling bearings, wIf the surface roughness value is Ra 0.32 μm, the bearing life is 2-3 times higher than that of Ra 0.63 μm, Ra 0.16 μm is 1 times higher than Ra 0.32 μm and Ra is 0.08μm than Ra when it is 0.4 times higher than D.16μm, and Ra is lower than 0.08μm, the change has little effect on fatigue wear. If the contact stress is too large, no matter how small the surface roughness value, the fatigue wear resistance isnot high. In addition, if the surface hardness of the part is higher, the surface roughness value should be smaller, otherwise the fatigue resistance will be reduced.

In addition, the alloy elements and the second phase and matrix structure in the material also have a major influence on wear resistance.

Prev: Application and features of taber wear tester معدات اختبار