The strength of cemented carbide is one of the key indexes of product toughness and impact resistance. In the field of metal cutting, such as discontinuous cutting and non-uniform cutting (including black leather cutting), tool fracture or breakage is the most important failure mode, so it puts forward very high requirements for the strength of cemented carbide matrix.

In the modern cutting, the introduction of tungsten carbide coatings technology makes the tool high temperature resistance, wear resistance, corrosion resistance and other properties have been greatly improved, to meet the requirements of high-speed processing. However, because the impact resistance of coated tools in high-speed machining is not ideal, most of the rough machining field with bad working conditions in China is still using non-coated tools with very low cutting efficiency. Through analysis and research thinks, coating process of cemented carbide substrate for a long time at 500 degreesto 1100 degrees, to be able to produce adverse effect to the strength of the matrix, the impact resistance performance of coated tools.

Test plan and test results

The test selects 6 kinds of k-series coated cemented carbide matrix brands, matrix WC particle size are 0.4 m, 0.6 m, 0.8 m, 1.5 m, 3.0 m and 4.0 m, the main component is WC+Co, containing trace additives. Select the same batch of raw materials for each brand, and press 30 strength test strips of 5.25mm 6.5mm 20mm respectively, and then sintering them together in the same furnace and vessel at one time. 10 grinding samples were taken for strength testing, and 10 unground blank samples were taken for CVD coating and 10 samples for PVD coating. The strength of cemented carbide matrix was tested by grinding the coated strip and testing the strength of cemented carbide matrix.

The change of strength of substrate with different particle size before and aftertungsten carbidecoatings. Except for the accidental factors such as abrasive sample and human operation in the test, it can be seen from figure 1 that the change trend of strength is obvious. The strength after sintering of the same matrix brand is >PVD coating, >CVD coating.

Related link:

http://www.wococarbide.com/Topic/index.html

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