The invention relates to a water-air-water
quenching heat treatment process for T10 steel screw taps for machines. The water-air-water
quenching heat treatment process includes steps of 1), heating the screw taps for the machines, preserving heat of the screw taps and austenitizing the screw taps for the machines; 2),
quenching and cooling the screw taps in water media; 3), taking the screw taps out of water and cooling the screw taps in air; 4), cooling the screw taps in water media until the temperatures of the screw taps reach the
room temperature; 5), shifting the screw taps for the machines into
tempering furnaces and carrying out
tempering heat treatment on the screw taps for the machines; 6), cooling the screw taps for the machines by air until the temperatures of the screw taps for the machines reach the
room temperature. Compared with the traditional process, the water-air-water quenching heat treatment process has the advantages that the water-air-water quenching heat treatment process is free of lampblack or fire hazards or harm to the
physical health of operators and is low in medium cost and high in economic benefit; international service standards can be completely met by the treated screw taps for the machines, the surface
hardness of the screw taps for the machines can reach 61HRC at least, the
hardness of cores of the screw taps for the machines can reach 50HRC at least, the
toughness of the screw taps for the machines can be improved as compared with conventional heat treatment, the service lives of the screw taps for the machines can be prolonged as compared with the conventional heat treatment, and deformation and
cracking of the screw taps for the machines can be greatly reduced.