Heat Treatment On The Mechanical Behavior Of High Wind Pressure Drilling Steel

The development of modern rock drilling machines and poor rock drilling working environment require higher and higher mechanical properties of drilling tools, coupled with longer and longer service life of that. Nowadays, however, the most popular failure modes of rock drilling tools on the market are wear failure and brittle failure. Particularly, the brittle failure usually happens in early rock drilling stage, which not only greatly decreases efficiency of rock drilling but causes human and material resources and waste of time as well.23CrNi3Mo, a rock drilling steel widely used in China, possesses good hardenability. It can be heat treated to obtain a good combination of strength and toughness by austenitization, quenching and tempering, which enables it to be often used to produce tools or parts under heavy-load and strong wear such as rock drilling tools. The Heat treatment is an important process in manufacturing rock drilling tools, and the optimization of heat treatment processes still has very great potential and vast space in promoting performance and service life.Quenching and tempering, as two of the most important heat treatment processes in the production of rock drilling tools, were carried on better designs in this work. Moreover, the relationships between heat treatment processes, corresponding structures and mechanical properties were investigated. It was illuminated the influence of combination of different temperatures in quenching and tempering on microstructures and mechanical properties of tested steel by means of Rockwell hardness test, Charpy impact test and Metalloscope etc., and the best heat treatment scheme of tested steel was obtained. The experimental results exhibited that toughness of tested steel was increased with the increase of quenching temperature in a certain range of temperature; the microstructure of the tested steel tempered at180℃was mainly lath martensite, which shown the highest hardness and Charpy impact energy; serious tempering brittleness took place when tested steel was tempered at between250℃and400℃; secondary hardening was generated when tested steel was tempered at between420℃and480℃.