The past and present of cemented carbide

       Cemented carbide was born in 1923. It was born in a legendary and awe-inspiring nation-the German nation.

At the end of the 19th century, people began to explore cemented carbide products in order to find new materials to replace high-speed steel to further increase metal cutting speed, reduce processing costs, and solve the problems of drawing tungsten filaments of bulbs.

In 1893, German scientists used tungsten trioxide and sugar to be heated to a high temperature in an electric furnace to prepare tungsten carbide, and tried to use its high melting point and high hardness to prepare wire drawing dies in order to replace diamond materials. Unfortunately, tungsten carbide has not been industrially applied due to its brittleness, easy cracking and low resistance. The first stage of the exploration of cemented carbide has temporarily failed.

In the 1920s, German scientist Karl Schroter discovered that pure tungsten carbide cannot adapt to the drastic stress changes formed in the drawing process. Only by adding low-melting metal to WC can the blanks have Certain patience. After a year of hard work, in 1923, Schroter proposed a powder metallurgy method to mix tungsten carbide with a small amount of iron group metals (iron, nickel, cobalt), and then press to shape and sinter at a high temperature of more than one thousand degrees. As a hard alloy, the world’s first real hard alloy was born.

People's continuous pursuit of hard alloys with higher hardness and better strength has produced many cutting-edge hard alloy production equipment. In 2005, the Zhu Min team of South China University of Technology proposed to introduce cold field plasma into mechanical ball milling. After plasma ball milling, the raw powders of W, C, and Co were pressed into a green body and directly sintered into a high-performance cemented carbide. A high-performance adjustable WC-Co cemented carbide was prepared in one step.

The production process of traditional WC-Co-based cemented carbide is generally more complicated, including reduction of tungsten oxide, carbonization of W, wet grinding of mixed powder, drying and granulation of mixed powder, green compaction, degreasing, and sintering. Obviously, this kind of production process is cumbersome, the production cycle is long, and it requires two high-temperature processes of carbonization and sintering, and the energy consumption is high.

It is the last day of 2020 today.Let's look forward to a better 2021.

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