Development of analyzing wear resistance of rubber materials for different wear models

Mill liner is an important part of mill. It has to withstand strikes and wear. Nowadays mill liners can be made of many different materials. In this work the focus is mainly on rubber liners. The aim of this thesis is to get better understanding how the properties of rubber affect to wear resistance of rubber material. Coumpounds including natural rubber and/or styrene butadiene rubber are widely used in mill liners. Their properties are good enough in applications where wear resistance is needed and they are also cost-effective. Moreover processing of these rubbers is not difficult. Many kinds of wear types occur with rubber materials during their use. The greatest of them is abrasive wear. Moreover impact wear, erosion wear and fatigue wear cause wearing of mill liners. Naturally each wear type has its own characteristics and different mechanisms. Sometimes testing of material wear is difficult and takes a lot of time. Different wear simulation methods can be used to reduce this work. One of them is 'Discrete Element Method' i.e. DEM. In this method Newton's laws of motion are used to describe motions of particles and their contact with next to each other particles. DEM also offers a possibility to simulate behaviour of mills in different situations. Thus, the method can be applied to evaluating wear of mill liners too. Material wear properties can be tested by different methods. Some of the can be mentioned. One of them is rotary tribometer which produces sliding to the surface of sample. The other is Goodrich-fleksometer which makes possible to compare hysteretic behaviour of vulcanized rubber compounds. Test methods which mimic abrasive, impact and erosion wear were selected to the experimental part. Mass reduction of samples was measured during testing. From these tests more information was gained of wear resistance of rubber materials which are used in mill liners when they are exposed to different wear models and selection of materials which can be applied to mill liners