What is the relationship between material hardness and wear resistance معدات اختبار

Product introduction

Abrasion resistance refers to the ability to resist friction. The factors of this ability depend not only on the composition, structure and performance of steel, such as hardness, carbide properties, quantity, shape and distribution, but also on the conditions of use. It is closely related to the drawing process, such as: there is a lot of dust layer sand on the surface of the wire.

Hardness is an important performance index to measure the softness and hardness of metallic materials. It can be understood as the ability of materials to resist elastic deformation, plastic deformation or damage, or it can be expressed as the ability of the material to resist residual deformation and anti-damage.

Without taking into account other factors, the higher the hardness, the better the wear resistance.id. The reason for the good wear resistance of cast iron is that gray cast iron contains flake graphite. We know that graphite has lubricating properties. Therefore, although cast iron has low hardness, it has good wear resistance due to graphite\'s wear reduction and surface finish. The higher the surface finish, the lower the friction. Relatively speaking, the hardness and wear resistance of the same material are different according to the surface treatment. proportional.

The higher the hardness of the material, the better the wear resistance, so the hardness value is often used as one of the important indicators to measure the wear resistance of the material.

However, the material with the best wear resistance does not necessarily have to have a high hardness. The most commonly used wear-resistant materials such as cast iron have a low hardness. In addition, the wear-resistant layer in the slide bearing is a Babbitt alloy, which is notit\'s so hard. To improve wear resistance in worm gear reducers, low hardness bronze alloys are generally used as worm gears. Wear resistance requires embedding and frictional compliance, that is, after the material is ground, it can form the friction surface where the concave and convex of the two friction surfaces match the fastest. If you only pursue surface hardness, hard materials are not easy to break in, but reduce the wear resistance of the friction surface.

According to the mechanism of wear:

If it is cutting wear, increasing the surface hardness can increase the wear resistance, and if it is impact wear, the effect of improvement will be worse.

Everyone should be familiar with high manganese steel, which has good impact and wear resistance. The austenite with good toughness undergoes strong work hardening during impact, which increases the surface hardnessid improves, achieves a good combination of hardness and toughness, and has good wear resistance.

If the material contains subgrades with a lamellar structure such as graphite, hexagonal boron nitride, iron sulfide, etc., these substances act as solid lubricants during friction and can improve wear resistance. Ordinary cast iron, sealing coating in aircraft engines, etc.

When plastic is rubbed against metal, plastic has good adaptability, and can also form a thin layer of transfer film on the metal surface to improve wear resistance. The use of PEEK valve plates instead of metal valve plates in reciprocating compressors is a good example.

Babbitt alloy is a very classic alloy under oil lubrication conditions. The structure is that the hard points are distributed over the soft phase. During the friction, the hard points play a supporting role, and the soft phase is somewhat worn awayand, and the formed gap simply absorbs the lubricating oil and improves the lubrication conditions.

High hardness does not mean good wear resistance. High hardness and good wear resistance, as an empirical preliminary judgment, it is still usable. If under the same conditions (same coefficient of friction, composition, structure, environmental conditions, etc.) there is a non-linear proportional relationship between hardness and wear resistance.

Wear should really be the category of contact surface tension, that is, under a certain pressure, the two moving metals interact and the ratio of material consumption. In this case

High hardness is better than low wear resistance;

Good lubrication is better than bad

The surface specific pressure is small and the wear resistance is good (including contact area and pressure);

Low surface roughness is better than high;

The internal structure is carbide better than other crystal structures (martensite, ferrite, etc.).

Prev: Research into wear resistance of different samples by TABER wear tester معدات اختبار