Material conveying wear-resistant pipeline is the lifeblood of industrial production, to ensure that the service life of the pipeline is safe and efficient production of the premise, straight pipe wear and bend compared to the general is much smaller.
Therefore, in the pneumatic conveying mainly consider the bending pipe wear. For example: Conveying materials are abrasive materials such as iron powder, using a common steel pipe, 2 hours of continuous transmission, bending pipe will be worn, if the bending radius is too small, the transport of brittle materials will increase the crushing rate; The bending radius is too large, the conveying of synthetic materials will produce drawing problems.
After my company’s long-term experience summed up, material impact or friction pipe wall and lead to the main factors of wear and tear are as follows:
- Physical property of conveying materials. including particle size and shape, concentration, hardness, moisture, crushing rate and adhesion.
- The condition of the conveying pipe. Including the material of the conveying pipe and metal composition, hardness, surface processing, inner diameter, layout and shape and so on.
- Conveying conditions. including the transmission flow velocity, material gas ratio, temperature and flow status.
In the actual transportation, the impact of the above factors on wear and tear is not a single existence, but the synthesis appears. Therefore, even if the same materials, using the same material conveying wear-resistant pipe-ceramic composite pipe, due to different transport conditions, the degree of wear is also different.
What affects surface wear?
The wear resistance of metallic materials can be measured by the hardness of the material. This is mainly because the hardness of the material reflects the abrasion resistance of the material surface. Therefore, the metal tissue which leads to the improvement of material hardness can generally improve the wear resistance of the material. However, due to the differences in the composition and microstructure of the material, the material may not be suitable for a particular wear condition, the hardness size can not be a sufficient basis for comparing the wear resistance of materials.
Solubility of crystal structure and crystal
Dense row of six square lattice metal materials, even if the friction surface in a very clean case, its friction coefficient is still 0.2~0.4, wear rate is also low. Cobalt is a typical material, so cobalt can be used as an important element of a wear-resistant alloy with high hardness.
A pair of metal friction pairs with poor miscibility in metallurgy can obtain lower friction coefficient and wear rate. such as steel formed a pair of friction pairs of materials in the solubility of the iron is very small, or the material is a intermetallic compound, then the friction pair of surface wear resistance is better.
- Temperature is mainly through the hardness, crystal structure changes, solubility and increase the oxidation rate of the impact of metal materials to change the wear resistance.
- The hardness of the metal usually decreases with the increase of temperature, so the temperature rises and the wear rate increases. Some friction parts (such as high temperature bearings) require the use of hot hard materials. The materials should contain cobalt, chromium, tungsten and molybdenum alloy elements.
- The solubility of the friction pair can be regarded as a function of temperature. If the temperature rises, the material is easily miscible and affects the wear rate of the material. In addition, the increase of temperature plays a catalytic role in increasing the oxidation rate, and has a significant effect on the types of oxides produced, so it also plays an important role in the friction and wear properties of metals.
Generally, the higher the hardness of the steel more wear-resistant
The higher the hardness of the material, the better the wear resistance, so the hardness value is often regarded as one of the important indexes to measure the abrasion resistance of the material.
But the material with the best wear resistance is not necessarily high hardness. The most commonly used wear-resistant materials such as cast iron hardness is not high, the engine camshaft is commonly used in cast iron. More typically, the wear-resistant layer of the sliding bearing is also not high in hardness. There are worm and worm gear reducer in order to enhance wear resistance, generally with the hardness of low bronze alloy gear Wear-resistant, the requirements of the embedding and friction compliance. Is the material after the grinding can be the fastest formation of two friction surface of the concave-convex surface with the rub;
If the pure pursuit of surface hardness, excellent material is not easy to running-in, but will reduce the friction surface wear resistance;
If it is cut into the wear, then improve the surface hardness can better improve the wear resistance, and if the impact of wear, the improvement will be less effective;
In general, the hardness of the lower than the low wear resistance, good lubrication when the time is good, the surface than the pressure small than large wear-resistant good (including contact area and pressure).