Through some domestic studies about the damage mode of tungsten carbide mining button, the analyses of mining button and shock resistance experiments, there are some reasons for the invalidation which are listed as below:
The operation condition of tungsten carbide mining button beading layer is relatively complicated. During the cutting of coal and rock, the mining button not only needs to bear cyclic pressure, tangential stress and the effect of impulsive load but also have to stand the long-time abrasive wear, the temperature rise caused by impacting force and the corrosion caused by corrosive medium.
The wear properties of the mining button are summarized as mechanical wear accompanied by thermal wear and abrasive wear of the grain. The beading layer of mining button has a higher requirement for properties. First of all, the beading layer should own its wear resistance which means that the beading layer has to bear the long-time abrasion from the coal layer during the coal mining. Under this condition, the higher the hardness and wear resistance are, the better the performance is. Besides, the effect of unavoidable impact load during the mining should be taken into consideration. If the hardness of the beading layer is too high and the metal toughness is low, the metal of the beading layer is easily broken.
Low impact resistance: Through the observation towards the damaged mining buttons, it is found that the damage of most buttons is not normal wear, especially in hard rock cutting.
Therefore, the hardness of the beading layer is not necessarily higher, the better. We should have an overall consideration to make the beading layer own a fine wear resistance. The so-called fine wear resistance refers to the appropriate reduction of hardness under the premise of high wear resistance. The fine damage resistance is improved by the appropriate durability. There is a certain matching relationship between the optimal comprehensive damage resistance and the hardness of the beading layer. The quantitative determination of this relationship may positively promote the significant improvement of the performance of the weld material of the picket weld layer. The quantification of this relationship may play an important role in promoting the properties of the welding material of the beading layer.
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