JPS6026817B2 - Current heating continuous annealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuous dawn anchoring of rolled steel plates using a current heating method in which electricity is applied directly to the steel plate. 4.Regarding a current heating type continuous sintering method that applies high frequency vibration to capture and accelerate the growth of recrystallized grains and shorten the overaging treatment time.

There are two methods for brazing cold-rolled steel sheets: electric heating and gas heating, with radiant tube gas heating being the most widely used.

The phosphor annealing equipment has a heating zone and a soaking zone in a non-oxidizing furnace that are continuous, and a strip-shaped steel plate passes through these zones continuously to be heated, soaked, and cooled. . The heating methods used in these conventional devices all involve installing a heating device such as a radiant tube in the furnace, raising the temperature inside the furnace to a predetermined temperature, and then passing the steel plate into this temperature atmosphere. This heated the steel plate. In the present invention, the technical concept is completely different from such conventional heating means, and electricity is directly applied to the steel plate passing through the furnace to heat the steel plate itself as a heating element. It is characterized by the fact that it promotes heating, uses minute high-frequency vibrations to promote grain growth, and promotes the diffusion of supersaturated solid solution carbon to improve deep drawing characteristics.

The basic concept of heating in the apparatus of the present invention is that, as shown in FIG. The heating power source 4 directly applies current to that part.

That is, an electric circuit is formed in which a current flows by using steel plates within a certain range as electric resistors. As a specific means of the circuit configuration, an electrode roll 5 is provided at a starting point and an end point that define a certain range of the traveling steel plate 3, and the steel plate 3 is energized using the electrode roll as a terminal. The steel plate 3 in the range to be heated by energization is bent into a loop shape by a plurality of electrically insulated guide rolls 6 and housed in an annealing furnace shell (not shown) formed by melting as a non-oxidation furnace. Additionally, attached equipment (not shown) is provided on the entrance and exit sides of the annealing furnace to electrically insulate the steel plate running outside the furnace. In the phosphor dulling method of the present invention, the steel plate itself is heated as a heating element, and this competitive recrystallization time is utilized to promote grain growth.

It is said that the promotion of recrystallized grain growth in European steel sheets is largely achieved by applying high-frequency vibrations using ultrasonic waves during continuous annealing and over-aging treatment. Adding high-frequency vibration with a minute amplitude of 4,
It is designed to produce an effect similar to that of high-frequency vibration caused by ultrasonic waves. That is, in the method of the present invention, an electromagnetic device 7 capable of generating magnetic flux in a direction perpendicular to the direction of current flow is provided in the steel plate passing through the hammer stroke, and the electromagnetic device 7 is excited by the magnetic field power source 8. do.

In this case, as shown in FIG. 2, the minute area portion d of the steel plate 3
Regarding s, a force F is generated that moves the plate in one direction in the width direction according to "Fleming's left-hand rule".

That is, as shown in FIG. 2, a force in the F direction acts on the small area portion ds of the steel plate that forms the intersection of the current 1 and the magnetic field B, causing the small area portion to move in the F direction. Therefore, in the method of the present invention, an alternating current is supplied to at least one of the heating power source 4 and the magnetic field power source 8,
By changing the direction of the current or magnetic field, the direction of the force F is changed.

Therefore, the movement direction of the minute area portion ds in the steel plate changes as the direction of the force F changes, and minute high-frequency vibrations occur, producing a result similar to when ultrasonic waves are applied. In the present invention, the steel plate to be hammered is heated by directly passing an electric current through it, and the effect of the current is used to electromagnetically apply minute amplitude vibrations to the steel plate to obtain the heat treatment effect. This is what I did.

Therefore, in the steel plate, the diffusion of atoms within the metal crystal is captured and the deep drawability can be improved, just as in the case where ultrasonic vibration is applied. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the principle of construction of the Rentsugi scorching anchor method according to the present invention.

FIG. 2 is an explanatory diagram of "Fleming's left hand rule" used in the method of the present invention. 3... Steel plate, 4...
Power source for heating steel plate, 5... Electrode roll, 6... Guide roll, 7... Electromagnetic device, 8... Power source for magnetic field.

hair illustration Figure 2

Claims (1)

[Claims] 1. Placing a pair of electrode rolls at separate positions on a running path of a steel plate that continuously passes through an inert gas atmosphere, forming an electric circuit using the steel plate running between the electrode rolls as a load resistor, In the current heating continuous annealing method in which the circuit is energized to heat the steel plate itself as a heating element, a magnetic circuit is provided in which a magnetic field intersects at right angles to the direction of movement of the steel plate passing through the electric circuit, for heating the steel plate. A current-heating continuous annealing method characterized by alternating at least one of a current and a current for generating a magnetic field to apply high-frequency vibration with minute amplitude to a steel plate.