Impact from wear out from the Low & medium stress .The particles is sliding or rubbing on the surface of basic plate which can produce the stress. Due to these worn out material’s stress is low, they can not change the size and can not break down. Also these particles’ attacking degree is low, people also use them to make the micromachining.
Impact from high/strong wear out/stress. Under the high pressure/stress, the grinding compound is worn out as pressed by both surfaces. The surfaces worn out can be showed like these ways : cutting,chipping,hard phase peeling (carbides, boron, etc.) or plastic deformation of the matrix.For example ,coal crusher. Therefore, the hard facing is a good balance among the productivity,ductility and hardness.
Serious worn out(chipping ) /high impact,for example the crusher hammer. The chipping worn out refers to “worn out is composed of low,medium and high impact “. There will be scratch and big chips ,also can cause the plastic deformation.The solution is to use the tough materials to resist the impact ( strength shall be applied in single touch point as well as multiply points touch ).
Adhesion/friction such as continuous casting rolls, shears and rolling bearings.When two pieces of metal parts are rubbed each other, materials from one side to another side ,this is called adhesion abrasion Such adhesion abrasion happens in high temperature ,high pressue and rubbing. In the unevenly surface touch, with the relatively movement, tough surface ,must be sheared immediately.Due to such worn out happens the micro level,people can not see any unevenness with naked eyes. The rate of adhesion worn out is subjected to these factors : force between two sides, relative speed, working condition temperature, surface conditions and surface friction factors.
Erosion wear ,for example ,the sludge excavator. The erosion wear is similar to the above wearing issues. Such worn out happens the high speed impact between solid granules or liquids. The rate of worn out is determined by the outer components degree and refection speed.
The physical feature of basic medium determine the worn out rate.
Cavitation corrosion ,for example ,the hydroelectric turbine blades. Cavitation happens the touched with high level liquid on solids’ surface . The cavitation is caused of liquid and inner explosive,producing worn out .
The Thermal fatigue ,for example ,forging tools, hot rolled sheets and roller.Such fatigue refers to the worn out from the heat recycling loading. When components are repeated by heating and cooling, they will become expansion and contraction. These process lead to surface crack, so we called it by thermal fatigue.
Fretting worn out ,such as : gear sprocket, guide rails, roller press machine.Fretting is caused by the repeated rolling or sliding between two parts. In such occasion,will appear the lost materials which are from the corrosive point or broken parts. Under the high pressure rolling or sliding components, will undertake heavy mechanic loading. Then the crack appears, and cracks will be spread under loading. Worse still , cracks will lead to flaking or planning.
Media’s corrosion ,for example ,the paper making screw conveyors ( hard face and tungsten carbide in nickel matrix ) or continuous casting rollers ( covered by martensitic stainless steel welding ). The corrosion worn out is a big and complicated topic. In order to meet this challenge, usually we used wrapping . And austenitic stainless steel (300 series) and nickel-based alloys are preferred. For the hard facing application ,corrosion is not the main problems. www.wxconveyor.com