The quality problem of high-speed steel composition improvement

The composition of high-speed steel determines that the quenching temperature of high-speed tool steel is very high, close to the melting point, and its purpose is to make alloy carbides more dissolved into the matrix, so that the steel has better secondary hardening ability. The hardness of high-speed tool steel increases after quenching, which is the first hardening, but the higher the quenching temperature, the lower the strength and toughness after tempering. After quenching, the hardness of low-temperature tempering below 350°C decreases and the tempering hardness increases gradually at temperatures above 350°C, and the second hardness peak appears when tempering within the range of 520~580°C (with different high-speed steel components and different tempering temperatures), and Exceeding the quenching hardness, this is secondary hardening, which is an important characteristic of high-speed tool steel.
High-speed steel There are two manufacturing methods for powdered high-speed steel, one is traditional ingot casting, and the other is manufactured by powder metallurgy. Traditional smelting and manufacturing are usually divided into two types: secondary refining (EAF+LF+VD) or electroslag remelting (ESR) processes. In the above methods, due to the slow cooling of the molten metal, the composition of high-speed steel will cause uneven segregation of alloys and alloys. The growth of carbides coarsens and affects the performance of high-speed steel.


Post time: Apr-26-2021