In the production process of cemented carbide die tooling, carbon content control is one of the primary items of quality control. Whether it is hydrogen sintering, vacuum sintering or other sintering, the carbon content in a controlled scale ensures that the product does not show carburization or Abnormal arrangements for decarbonization. Cobalt magnets are usually used to measure the carbon content of the alloy. According to the force requirements and practical experience of the top hammer, the carbon amount of the big top hammer is controlled in the carbon-poor zone of the two-phase zone.
Large top hammers often have destructive cracks during use. According to the analysis of the results of anatomy of this type of hammer, this situation will appear if the temperature is too low or too high. When the temperature is low, the internal arrangement structure of the top hammer appears under-burning or incomplete crystal growth, and the pores are enlarged, which greatly reduces the alloy performance, and cannot withstand the transmission of the composition pressure to the top hammer, resulting in destructive rupture of the top hammer: temperature deviation High, the alloy appears to be thicker or the entire grain size increases, and the coarse WC grains become the source of fracture, causing the top hammer to penetrate the crystal fracture.
Cemented carbide mould
Improper sintering temperature is one of the primary reasons for the formation of a low-life hammer. Therefore, it is important to properly control the sintering temperature. It should be controlled so that the WC crystal grains grow completely without causing the pinch to be coarse.
In the production process, the manipulation of raw and auxiliary materials should also be satisfied, such as removing the carrier of the die toolinging agent.
For solid big top hammers, removing the forming agent is an important link related to the control of the top hammer's carbon content. Which method is used to remove the die toolinging agent has different requirements for the carrier, but one thing is common, that is, the amount of carrier used should be quantitatively controlled, and the scale of fluctuations is small. Generally, large-cavity top hammers are produced. If hydrogen is used to remove the forming agent, high-pressure hydrogen is suitable.
Hard alloy hardness testing mainly uses Rockwell hardness tester to test HRA hardness value. The PHR series portable Rockwell hardness tester is very suitable for testing the hardness of cemented carbide. The weight accuracy of the instrument is the same as that of the desktop Rockwell hardness tester, and it is very convenient to use and carry.
Cemented carbide is a kind of metal. The hardness test can reflect the difference in mechanical properties of cemented carbide materials under different chemical composition, arrangement structure and heat treatment process conditions. Therefore, the hardness test is widely used in the inspection of cemented carbide properties and the supervision of heat treatment. The correctness of the process and the study of new materials.
Features:
It is a non-destructive experiment, and the experimental method is relatively simple. The hardness test of cemented carbide has a strong adaptability to the shape and size of the test piece, and the experiment efficiency is high. In addition, there is a certain correspondence between the hardness of cemented carbide materials and other physical properties. For example, cemented carbide hardness test and tensile test are basically testing the ability of metal to resist plastic deformation, and these two tests are testing the similar properties of metal to some extent. Therefore, the test results are completely comparable to each other. Cemented carbide tensile test equipment is huge, complex operation, sample preparation, and low test efficiency. For many metal materials, there is a conversion table for hardness test and tensile test. Therefore, when testing the mechanical properties of cemented carbide materials, more and more hardness tests are used instead of tensile tests.
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