Induction tempering of stepped billets from steel 40x. The production of stepped billets (Fig. 1) made of 40X steel, implemented by heating an HDTV component instead of heating in the H-60 chamber electric furnaces, was introduced into production.
Image1. Sketch the blank.
The step billet is heated on a semi-automatic machine ZS-406 in a multi-turn horizontal inductor (Fig. 2) of a methodical action. The inductor is powered from the HPV-100/2400 current frequency converter through the station MGZ-102.
Image2. Sketch of multi-turn horizontal inductor.
Billets are loaded through the loading tray of the machine. Every 120 seconds, the plunger delivers the next billet to the inductor, and the heated billet enters the cooling device.
Cooling medium is water with a temperature of 35-85 ° C. The heating and holding time in the inductor is 18 minutes. Additional heating of blanks for small diameter and temperature equalization by volume is carried out by a special secondary winding installed at the end of the inductor. To increase the heating rate of the blanks is an additional winding installed at the beginning of the inductor. The workpiece is centered in the inductor with a special device. The installation has the following parameters: I = 42 ± 10 A; U = 360 ± 20 V; W = 15 ± 5 kW.
The study of the dependence of the metal temperature on the heating time in the inductor showed that the temperature of the metal on the workpieces reached the set (445-505 ° C) after 13 minutes. Exposure at a heating temperature of 5-7 minutes.
After tempering, the workpiece is subjected to 100% hardness control; hardness must be within HB 302-375. The scatter of hardness values over the length and depth of the billet that has undergone heat treatment using HDTV is HB 22, while it is HB 32 during furnace heating.
The use of high-frequency heating made it possible to increase labor productivity in tempering operations by 6 times, reduce energy consumption and gave a significant economic effect.
N. M. Votchenko, B. D. Artemiev, V. P. Korolev, M. M. Ginzburg
ISSN 0026-0819. “Metallurgy and heat treatment of metals”, No. 9. 1968
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