APPARATUS AND METHOD FOR HEAT TREATMENT OF A LONG-LENGTH PRODUCT WITH AN L-SHAPED PROFILE WITH A SOLE, NECK, HEAD Russian patent published in 2021 - IPC C21D9/04 C21D1/10 

FIELD: heat treatment.

SUBSTANCE: invention relates to apparatuses for heat treatment of a long-length product with an L-shaped profile with a sole, neck and head, and to methods for heat treatment of said product. The apparatus comprises a conveyor for continuous movement of the product at a preset constant speed, a high-frequency current source, an inductor for heating the contact surface area of the head of the product, configured to be installed parallel to the contact surface of the head of the product, and electrically connected with the high-frequency current source, a tubular element with holes for water-air spray cooling of the heated area of the contact surface of the product, and a heat-resistant screen. The inductor is made with a length of no less than 3.5 N and a width of no less than (H-5), wherein H is the height of the contact surface of the head, mm, the tubular element comprises tubes with holes, wherein the tubular element is located directly behind the inductor, fastened rigidly at the same level with the inductor and separated therefrom by the heat-resistant screen. The method involves continuous movement of the product on the conveyor at a speed of 400 to 800 mm/min with the product passing through a local induction heating area, wherein the local induction heating area is made with a length of no less than 3.5 N and a width of no less than N-5, wherein H is the height of the contact surface of the head, mm, an alternating electromagnetic field with a frequency of 100 to 300 Hz for heating the product to a temperature of (Ac₃+45°C)-(Ac₃+75°C) with the heating rate of (32-68) °C /s, wherein the subsequent water-air sprayer cooling is executed at the rate of (10-15) °C /s, forming a hardness gradient from the surface into the base of the product to the depth of 12 to 15 mm.

EFFECT: increased wear resistance of the contact surface of the head of the L-shaped profile.

11 cl, 17 dwg