METHOD OF LASER HARDENING OF STEEL PARTS Russian patent published in 2024 - IPC C21D1/09 

FIELD: performing operations.

SUBSTANCE: invention relates to heat treatment, namely to laser heat treatment of steel parts. Process of cooling liquid supply is simulated with determination of its required flow rate through each tube to ensure the specified cooling rate. Part surface is heated and the part surface is continuously cooled to metal by cooling liquid to form, after cooling, a hardening path with a completely martensite structure. Cooling liquid is supplied directly to the surface section by means of tubes, each of which is made with possibility to control flow rate of cooling liquid and is installed with possibility of changing its position in direction of relative movement of laser beam and part. Cooling fluid flow rate through each tube is controlled depending on the part surface heating temperature difference between the sensor close to the laser beam exposure zone, and a sensor in the zone after the action of the cooling liquid along the hardening path, which determines the cooling rate of the surface layer. Said temperature difference is determined by the expression: ΔT_i = V_cool⋅L₁(R₁)⋅V_p^-1, where ΔT_i is the part surface heating temperature difference, V_cool is the part average cooling rate, L₁(R₁) is the distance between the temperature sensors, V_p is the part movement speed. If the obtained cooling rate of the part deviates from the preset value, the control unit, using the appropriate regulator, changes the coolant flow rate through the appropriate tube to eliminate the above difference in readings of temperature sensors.

EFFECT: obtaining a fine structure of martensite and high uniformity of properties of the hardened layer.

1 cl, 4 dwg