The invention relates to a
quenching method for a 20CrNiMo material
drill bit. The method comprises the following: a first
quenching step, which comprises the steps of heating up a
drill bit workpiece after being carburized, heat preserving, discharging from a furnace and
oil cooling, washing with clear water, first
tempering, heat preserving for at least three hours, naturally cooling, and discharging from the furnace and
air cooling to the
room temperature; and a second
quenching step, which comprises the steps of second heating up the
drill bit, heat preserving, discharging from the furnace and second
oil cooling, extracting oil, washing with clear water, second
tempering, and discharging from the furnace and
air cooling to the
room temperature. Due to the adoption of the two-time quenching process and a display of detected data from a test, the
hardness of the workpiece of the 20CrNiMo material
drill bit is uniformly distributed, the
hardness value of the workpiece of the 20CrNiMomaterial
drill bit reaches to Rockwell
hardness 58-61, and the metallurgical structure of the workpiece of the 20CrNiMo material
drill bit is further refined; moreover, the invention has the advantages of prolonging the service life of the 20CrNiMo material drill bit, increasing economic benefit, reducing replacement times and reducing production cost.