JP2009167440A - Heat treatment apparatus for steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus which stably secures a width C to be induction-heated and a width D in which the high temperature is maintained, up to end parts even if a steel sheet is thin, when the steel sheet 20 is induction-heated with a moving system while the both ends are pulled by a sandwiching device 21 that extends over a full width. <P>SOLUTION: The heat treatment apparatus for the steel sheet is directed at sequentially applying induction heating and subsequent water cooling to the steel sheet 20 while moving the steel sheet in its longitudinal direction for the purpose of crystal grain refining treatment in which heat treatments for rapidly heating and subsequently rapidly cooling the steel sheet 20 are repeatedly carried out; and has a movable frame 31 which holds both ends of the steel sheet 20 in its longitudinal direction with the sandwiching device 21 and pulls the both ends with a tension-imparting member 32; a tilted table 34 which mounts the movable frame 31 thereon in a form of making the steel sheet 20 take such an attitude that the width direction is horizontal and the longitudinal direction is tilted, and moves the steel sheet 20 in the longitudinal direction by linearly moving the movable frame 31; an inductor 22 for heating the moving steel sheet; and a water spraying portion 23. The amount of water to be sprayed from the water spraying portion 23 is reduced in the vicinity of the sandwiching device 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steel sheet while relatively moving the steel sheet and the inductor in the longitudinal direction of the steel sheet for a grain refinement process that is performed by repeatedly performing a heat treatment that applies rapid heating and subsequent quenching to the steel sheet. The present invention relates to a steel plate heat treatment apparatus that sequentially applies induction heating and subsequent rapid cooling.

  With regard to the heat treatment of steel, it is possible to obtain ultrafine-grained steel materials by repeatedly performing a heat treatment that is rapidly heated immediately above Ac3 and then rapidly cooled, and that the strength and toughness both increase if the crystal grains are refined. The hardness and toughness are both achieved and the fracture toughness is achieved by simultaneously forming hardness and toughness by repeating rapid heating and quenching that reciprocate between the austenitizing temperature range and martensitic transformation temperature range multiple times on the surface of the steel. It is also known that rapid heating can be realized by high-frequency induction heating and rapid cooling by water cooling.

  In addition, for a finite-length steel sheet (see, for example, Patent Document 1), a steel sheet heat treatment apparatus suitable for carrying out a grain refinement process that increases fracture toughness while maintaining high hardness has been developed. A support member that engages both ends of the steel sheet in the longitudinal direction and holds the steel sheet in a state in which the longitudinal direction is oriented in the vertical direction and in an allowable bending state, and a lifting mechanism that moves the steel sheet in the longitudinal direction via the support member And a heat treatment unit that combines an inductor for moving heating of the steel plate and a water discharge part for rapid cooling of the steel plate, and a horizontal plane adjustment mechanism for adjusting the position and in-plane orientation by moving the heat treatment unit in the horizontal plane And. And this steel plate heat treatment apparatus is capable of continuing the heat treatment even if it is bent by the heat treatment, even if it is bent by the heat treatment even if the heat treatment is repeated by holding the steel plate of a finite length from both ends in a state where it is allowed to bend. It has become.

JP 2006-348339 A

  However, in such a vertically held and vertically moved steel plate heat treatment apparatus, it is difficult to reduce the cost of the apparatus and equipment, and it is difficult to reduce the work load because the setting work of the steel plate to be processed must be performed carefully. For this reason, practical heat treatment for grain refinement of steel sheet is put to practical use by horizontal movement that has a proven track record, that is, a moving heating method in which the object to be processed is horizontally placed and the inductor and the water discharger are moved relative to each other. It is desirable. In order to achieve this, it is conceivable that both ends of the finite-length steel plate are restrained by tension and subjected to rapid heating and quenching while applying a tensile force in the longitudinal direction to the steel plate, but warping while suppressing the residual stress within an allowable range. It is required to sufficiently suppress undesired deformation caused by heat treatment such as twisting and swell. Therefore, a specific problem is how to put the finite-length steel plate in a specific manner, in particular, how to embody the tensile restraining means.

  FIG. 4 is a view for further explaining the problem of the present invention, in which (a) is a plan view where the thick steel plate 10 is horizontally placed and heated and moved, (b) is a front view thereof, (C) is a plan view where a thin steel plate 20 is placed horizontally and heated by heating, (d) is a front view thereof, and (e) is an enlarged vertical cross-sectional view of the thick steel plate 10 as viewed in the direction of arrow AA. (F) is the longitudinal cross-sectional enlarged view of the BB arrow which concerns on the steel plate 20 of a thin plate.

The material of the steel plates 10 and 20 is one in which crystal grains become finer by repeated rapid heating and rapid cooling, and examples thereof include JIS G3128 (SHY) and JIS G4103 (SNCM) (see Patent Document 1).
The size of the steel plate 10 to be a thick plate is typically about 16 mm thick x 1200 mm wide x about 6000 mm long, but other sizes may be used. As a guide, the thickness is 10 to 25 mm and the width is 900 to 900 mm. The length is 1200 mm and the length is 2000 to 6000 mm.
The size of the thin steel plate 20 is typically about 5 mm thick x 700 mm wide x about 1200 mm long, but other sizes may be used. As a guide, the thickness is 3 to 12 mm and the width is 300 to 800 mm. The length is 500 to 2000 mm.

  When the finite-length workpiece is a thick steel plate 10 (see FIGS. 4A and 4B), for example, a small hole is formed near the center of both ends of the steel plate 10 and a wire-like tension is formed there. The restraint tool 11 is connected, and a tensile force in the longitudinal direction is applied to the steel plate 10 via the tension restraint tool 11 (see the short-wave line arrow). Further, the lower surface of the steel plate 10 is supported by several supporters 12 with rollers arranged at an appropriate pitch of, for example, 500 to 100 mm, with the steel plate 10 being horizontal, i.e., the longitudinal direction and the width direction are horizontal and the thickness direction is vertical. . Then, the necessary heat treatment is performed on the steel sheet 10 by moving the heat treatment unit including the preceding inductor 13 and the subsequent water discharge section 14 from one end of the steel sheet 10 to the other end. In this case, the steel plate 10 can be dispersedly supported at multiple points while avoiding undesired interference between the heat treatment unit and the support tool 12 by moving the support tool 12 up and down in order during the movement of the heat treatment unit, resulting in its own weight and transformation. The deformation of the steel plate 10 generated is suppressed and falls within the allowable range.

  On the other hand, when the finite-length workpiece is a thin steel plate 20 (see FIGS. 4C and 4D), a holding method such as the above-described thick plate is not suitable. When the steel plate 20 is placed horizontally, since the plate thickness is thin, the support on the lower surface can be omitted. However, since the tensile restraint at both ends cannot be completed locally, a tensile force can be applied uniformly to the entire area of the steel plate 20. Because it is required. Therefore, both ends of the steel plate 20 are constrained by the clamping tool 21 extending over the entire width, and a tensile force in the longitudinal direction is applied by pulling through the clamping tool 21 (see the short wave line arrow). Then, the heat treatment unit including the preceding inductor 22 adapted to the cross-sectional shape of the steel plate 20 and the subsequent water discharge portion 23 is relatively moved several times from one end to the other end of the steel plate 20, thereby crystallizing the steel plate 20. Heat treatment necessary for grain refinement is performed.

  By the way, in the finite-length steel plate heat treatment with lateral placement and lateral movement, the cooling effect that occurs on the upper surface of the steel plate where the cooling water tends to stay and the lower surface of the steel plate where the cooling water is likely to fall off so that the quenching performance is the same on both sides of the steel plate. In order to reduce or eliminate the difference, the amount of water on the lower surface is increased than the amount of water on the upper surface. Thus, since the cooling water on the upper surface is relatively small, in the case of the thick steel plate 10 (see FIG. 4 (e)), when the cooling water 15 is blown from the water discharge portion 14 to the steel plate 10, the injection direction η is backward. It only needs to be inclined (left in the figure). The cooling water 15 spreads in the upper surface of the steel plate 10 where the water discharge unit 14 has passed and flows down from the edge of the steel plate 10, and the cooling water 15 does not flow unnecessarily below the water discharge unit 14 or the inductor 13. Therefore, as the instantaneous width of the moving heating with respect to the steel plate 10, the induction heating width C of the portion of the steel plate 10 facing the inductor 13 and the high temperature maintenance width D from there to the water discharge position of the water discharge unit 14 are stable. Secured.

  However, in the case of the thin steel plate 20 (see FIG. 4F), it is difficult to secure the high temperature maintenance width D directly under the water discharge portion 23, and even the induction heating width C directly under the inductor 22 may not be stable. When the steel plate 20 is thinned, the heat capacity is reduced and the amount of heat in the high temperature maintaining width D portion is reduced. Therefore, the coolant 24 that is undesirably shunted or scattered forward is contrary to the amount that flows backward. Although it is small, it does not evaporate and enters directly under the water discharge part 23 and cools the steel plate 20 sooner than planned. Therefore, the high temperature maintenance width D often changes or disappears. Further, when the heat treatment is performed up to the end of the steel plate 20, the holding tool 21 extends over the entire width of the end of the steel plate 20 (see the portion indicated by the two-dot chain line in the figure). Even if the water drainage is improved, the cooling water 24 that has bounced off from the holding tool 21 or the cooling water 24 that has risen without escape is likely to overflow toward the water discharge section 23 or the inductor 22. The fluctuation of the instantaneous width (C + D) of moving heating is further increased.

Therefore, it is technical to improve the steel plate heat treatment apparatus so that the induction heating width C and the high temperature maintenance width D are stably secured even when the steel plate is thin when the both ends of the steel plate 20 are pulled by the moving method. It becomes a difficult task.
Moreover, even if the both-ends holding in that case is performed with the clamping tool 21 over the entire width, it is further improved to improve the steel plate heat treatment apparatus so that the induction heating width C and the high-temperature maintenance width D are stably secured to the ends. It becomes a technical issue.

  The steel plate heat treatment apparatus of the present invention (Solution means 1) was devised in order to solve such a problem, and crystal grains are obtained by repeatedly applying heat treatment to a steel plate to apply rapid heating and subsequent rapid cooling. In a steel plate heat treatment apparatus for sequentially applying induction heating and subsequent water cooling to the steel plate while moving the steel plate in the longitudinal direction for the refinement treatment, both ends in the longitudinal direction of the steel plate are sandwiched over the entire width. A holding mechanism that pulls the steel plate in the longitudinal direction thereof, and the holding mechanism is mounted in such a manner that the steel plate takes a posture that is horizontal in the width direction and inclined in the longitudinal direction, and the holding mechanism is moved linearly. And an inclined table for moving the steel plate in the longitudinal direction thereof, and the steel plate mounted on the inclined table and held by the holding mechanism is confronted with a partial section in the longitudinal direction over the entire region in the width direction. Yo And an inductor for rapid heating arranged on the tilting table adjacent to or near the inductor and facing the steel sheet across the entire area in the width direction and in a partial section in the longitudinal direction. And a water discharge section for rapid cooling arranged as described above.

  The steel plate heat treatment apparatus according to the present invention is (the solution means 2), the steel plate heat treatment apparatus of the solution means 1, wherein a water supply circuit for supplying cooling water to the water discharge section varies the amount of water supply, whereby the water discharge section. However, when water discharge is started near the holding device, the water discharge amount of the water discharge portion is suppressed to be small, the water discharge amount of the water discharge portion increases as the water discharge portion moves away from the clamp device, and the water discharge portion is The water discharge amount of the water discharge unit is maintained constant after leaving the holding tool.

  Further, the steel plate heat treatment apparatus according to the present invention (Solution means 3) is the steel plate heat treatment apparatus of the above solution means 1 and 2, wherein the water discharge portions are provided on both sides of the inductor, and the tilt table swings. It is characterized in that the height of both ends can be changed alternately.

  In such a steel plate heat treatment apparatus of the present invention (Solution 1), the heat treatment of the finite length steel plate is performed not by vertical holding but vertical movement, and by horizontal tilting, not by vertical tilting. As a result, the inclination of the upper surface of the steel sheet is added to the angle of water discharge with respect to the upper surface of the steel sheet, and the angle of water discharge with respect to the horizontal is expanded. As a result, the amount of cooling water that enters the water discharge part and the inductor undesirably decreases. Therefore, even if induction heating is performed by a moving method while pulling both ends of a thin steel plate, not only the induction heating width but also the high temperature maintenance width is stably secured. The appropriate lower limit of the inclination angle is where the amount of cooling water entering the lower part of the water discharge part is sufficiently small from the viewpoint of quality, and the upper limit is that the both ends in the longitudinal direction of the steel sheet can be pulled from the viewpoint of workability. The tilt setting work to be performed can be performed without much difference from the horizontal setting work, and the standard range is 7 ° to 15 °.

  Moreover, in the steel plate heat treatment apparatus of the present invention (solution 2), the water discharge amount is reduced as the holding tool is closer at the start or immediately after the heat treatment affected by the holding tool. Even if holding the both ends of the steel plate with a clamping device over the entire width, the amount of water that bounces back with the clamping device and returns to the water discharge section is small, and the cooling water does not rise or overflow near the clamping device. As a result, the induction heating width and the high temperature maintenance width can be stably secured up to the end portion.

  Furthermore, in the steel plate heat treatment apparatus of the present invention (solution means 3), every time moving heating is completed, the inclined state of the tilting table is alternately switched, and the selected state of the water discharge unit used for rapid cooling is selected. Are also switched alternately, and water is discharged only from one of the water discharge portions on both sides of the inductor that can be cooled after heating. As a result, when the finite-length steel plate is reciprocated in order to repeat the moving heating required for crystal grain refinement, the tilting and tilting heat treatment can be performed in either reciprocation. For this reason, the time required for crystal grain refinement by repeated heat treatment of tilting tilting is shortened.

About the steel plate heat processing apparatus of this invention, the specific form for implementing this is demonstrated by the following Examples 1-2.
The embodiment 1 shown in FIGS. 1 and 2 embodies the above-described solving means 1 and 2 (claims 1 and 2 as originally filed), and the embodiment 2 shown in FIG. Means 3 (claim 3 as originally filed) is embodied.
In these drawings, for the sake of simplicity, fasteners such as bolts, coupling tools such as hinges, drive sources such as electric motors, transmission members such as timing belts, electric circuits such as motor drivers, controllers, etc. The electronic circuit and the like are not shown in the figure, and are illustrated in a simplified manner with a focus on what is necessary and related to the explanation of the invention. Further, in the illustration thereof, the same components as those described in FIG. 4 are denoted by the same reference numerals.

  About the Example 1 of the steel plate heat processing apparatus of this invention, the specific structure is demonstrated referring drawings. 1A is a plan view of the steel plate holding mechanism 31 + 21 + 32, FIG. 1B is a front view of the steel plate heat treatment apparatus 30 with the water receiver 37 removed, and FIGS. It is a front view. FIG. 2A is a symbol diagram of a water supply circuit having a variable amount of cooling water.

  This steel plate heat treatment apparatus 30 (see FIG. 1) is a method of repeatedly performing a heat treatment that applies rapid heating and subsequent quenching as crystal grain refining treatment to the thin steel plate 20 described above. While moving in the longitudinal direction, rapid heating is applied to the steel sheet 20 by induction heating, and rapid cooling is applied to the steel sheet 20 by subsequent water discharge cooling. In order to carry out, the inductor 22 and the water discharge part 23, the steel plate holding mechanism 31 + 21 + 32 shown in the figure, the inclined base 34, the legs 35 and 36, the water receiver 37, the high-frequency power supply device and the water cooling device (not shown) are controlled. With equipment.

  The steel plate holding mechanism 31 + 21 + 32 includes a movable frame 31 that is mounted on the inclined base 34 so as to be linearly movable so as to hold the both ends of the steel plate 20 in the longitudinal direction and pull the steel plate 20 in the longitudinal direction. A holding tool 21 fixed to the frame 31, another holding tool 21 that is disposed opposite to the holding tool 21 and is not fixed to the movable frame 31, and a pair of holding tools 21 that act on the non-fixed holding tool 21, A tensile force applying member 32 that applies a tensile force to the steel plate 20 between the pair of sandwiching devices 21 and 21 by pulling 21 apart is provided. It is sufficient that the clamping device 21 extends over the entire width of the steel plate 20, but it is easy to use the clamping device 21 that is fixed at the lower side and swings on the upper side so that the cross-sectional shape becomes a U shape when sandwiched and becomes an L shape when released. The tension applying member 32 is embodied by a hydraulic cylinder or the like, and a proportional electromagnetic relief valve or the like is used for the hydraulic pressure supply unit in order to always generate a constant tensile force, and a pressure sensor and an amplifier are used for pressure control. Thus, automatic control is performed while applying pressure feedback, and the tensile force controlled with high accuracy is stably applied over the entire length of the steel plate 20.

  The tilting table 34 is mainly composed of a linear / parallel line frame having a length approximately twice as long as the movable frame 31 longer than the steel plate 20, and the movable frame 31 is mounted on the inclined table 34 so that a constant speed is achieved in the longitudinal direction. As an additional mechanism necessary for linear movement and reciprocation at high speed, for example, a linear guide member such as an LM guide, a transmission member such as a ball screw, and a drive source such as a servo motor are provided. One end (left end in the figure) of the inclined base 34 is supported by a short leg 35, and the other end (right end in the figure) of the inclined base 34 is supported by a tall leg 36. Is inclined from the horizontal by an angle θ. The inclination angle θ may be fixed at, for example, 10 °. In the steel plate heat treatment apparatus 30, the leg portion 36 is, for example, a cylinder mechanism or a lock mechanism so that the inclination angle θ can be variably set within a range of, for example, 5 ° to 20 °. It is embodied in and can be stretched.

When the movable frame 31 is mounted on the tilting table 34, the mounting frame, the guide, and the like are provided so that the longitudinal directions of the two frames are aligned and the width direction is kept horizontal. 34 is equipped with a steel plate holding mechanism 31 + 21 + 32 in such a manner that the steel plate 20 takes a posture that is horizontal in the width direction and inclined in the longitudinal direction. It is to be moved.
The water receiver 37 is externally mounted on the inclined base 34 so as to surround from the bottom to the side of the inclined base 34 in order to prevent the cooling water from flowing down and dissipating, and the water receiver 37 of the water receiver 37 is used to collect the cooling water. A drain outlet is formed at the end, and a drain hose is connected thereto.

  The inductor 22 is made of a good electrical conductor such as a water-coolable copper tube, is wound in a coil shape, and is mounted at a substantially central position of the inclined base 34. Since the position surrounds the linear moving path of the steel plate 20 held by the steel plate holding mechanism 31 + 21 + 32, the inductor 22 is supplied with a high-frequency current from a high-frequency power supply device (not shown) through a cable or a transformer (not shown). And the opposite part of the steel plate 20 is induction-heated. Moreover, since the inductor 22 is for moving heating, with respect to the facing state with respect to the steel plate 20, the steel plate 20 faces the steel plate 20 over the entire area in the width direction of the steel plate 20, and the steel plate 20 in a partial section in the longitudinal direction of the steel plate 20. It comes to confront with.

  The water discharger 23 is mounted on the tilting base 34 and is located on the immediate side of the inductor 22 in order to perform rapid cooling after the rapid heating of the moving steel plate 20, and is also held by the steel plate holding mechanism 31 + 21 + 32. The steel plate 20 and the steel plate 20 are opposed to each other in the width direction and in a part of the longitudinal direction. Since the heat treatment is performed while moving the steel plate 20 obliquely along the inclination of the inclined table 34, the water discharger 23 is located obliquely below the inductor 22 (lower left in the figure), and the movement path of the steel plate 20. Is attached to the tilting table 34 so as to surround. A large number of injection holes are formed in the water discharge portion 23 in a row in the width direction of the steel plate 20, and at the time of water discharge, cooling water adjusted to an appropriate amount from the water cooling device via the water supply circuit is supplied from each injection port to the steel plate 20. It is designed to be jetted towards.

Although the upper part and the lower part of the water discharge part 23 are communicated with each other and the lower injection port is formed wider than the upper injection port, it is possible to easily embody water discharge with different water amounts in the upper and lower sides. The water discharge section 23 is divided into an upper water flow portion and a lower water flow portion so that the upper and lower water supply amounts can be adjusted and set independently, and a water supply line is connected to each.
The water supply circuit (see FIG. 2 (a)) is provided as a part of the cooling device or provided in a water supply line connecting the cooling device and the water discharger 23, and supplies the cooling water to the water discharger 23. However, the amount of water supplied to the water discharger 23 can be varied separately up and down.

  Specifically, a variable throttle valve 51 and an electromagnetic switching valve 41 connected in series, a variable throttle valve 52 and an electromagnetic switching valve 42 connected in series, a variable throttle valve 53 and an electromagnetic switching valve 43 are provided. What is connected in series is connected in parallel, and is inserted into a water supply line from the water supply source to the lower part of the water discharger 23, thereby adjusting the water supply amount below the water discharger 23 and high-speed multistage switching. Is possible. The variable throttle valve 54 and the electromagnetic switching valve 44 are connected in series, the variable throttle valve 55 and the electromagnetic switching valve 45 are connected in series, and the variable throttle valve 56 and the electromagnetic switching valve 46 are connected in series. By connecting them in parallel and inserting them into the water supply line from the water supply source to the upper part of the water discharger 23, it is possible to adjust the water supply amount on the upper side of the water discharger 23 and to perform high-speed multistage switching. .

  The control device (not shown) is embodied by a programmable sequencer or computer, and performs control related to energization of the inductor 22, water discharge of the water discharge unit 23, and movement of the movable frame 31. To describe the control in detail, by controlling the electromagnetic switching valves 41 to 46, for example, only the electromagnetic switching valves 41 and 44 are turned on (open, water flow) when the water discharger 23 starts water discharge near the holding tool 21. In this case, the water discharge amount of the water discharge unit 23 is suppressed to be small, and when the water discharge unit 23 is slightly separated from the holding tool 21, for example, in addition to the electromagnetic switch valves 41 and 44, the electromagnetic switch valves 42 and 45 are also turned on (open, water flow). By increasing the water discharge amount of the water discharge portion 23, and when the water discharge portion 23 is sufficiently separated from the holding tool 21, for example, all the electromagnetic switching valves 41 to 46 are turned on (open, water flow) to discharge the water discharge amount of the water discharge portion 23. After further increasing Is as it is adapted to be maintained at a constant after.

  About the steel plate heat processing apparatus 30 of this Example 1, the use aspect and operation | movement are demonstrated referring drawings. FIGS. 1C to 1E are all front views of the steel plate heat treatment apparatus 30, and FIGS. 2B to 2C are all enlarged longitudinal sectional views of the heat treatment portion.

  In the preparatory stage, the inductor 22 and the water discharger 23 suitable for the size of the steel plate 20 are mounted on the inclined base 34 to adjust the position and posture, and the throttle condition of the variable throttle valves 51 to 56 is adjusted to adjust the water discharger 23. Is set for each stage of multistage switching. In addition, for the energizing current of the inductor 22, the frequency thereof, the timing of changing the water discharge amount of the water discharge section 23, etc., values suitable for the steel plate 20 are selected and set in the control device as parameters.

  To give one typical numerical example, the steel plate 20 is made of SHY, and the size is 5 mm thick × 700 mm wide × 1200 mm long. The feed rate of the steel plate 20 is 2.5 mm / s during heat treatment and 100 mm / s for return. The electrical conditions are a current of 250 A, a voltage of 390 V, and a frequency of 30 kHz. The amount of water discharged from the water discharge section 23 is 10 L / min on the upper side for the first 5 seconds, 20 L / min on the lower side, 15 L / min on the upper side for the next 5 seconds, and 30 L / min on the lower side. After that, the upper side is 30 L / min and the lower side is 60 L / min.

After the initial setting and adjustment of the steel plate heat treatment apparatus 10, the pair of clamps 21 and 21 provided at both ends of the movable frame 31 on the tilting table 34 are opened, and an available crane or steel plate adsorption machine can be used. The steel plate 20 to be treated is held by a handling device equipped with the above and the like, the steel plate 20 is inserted into the inductor 22 and the water discharger 23, and both ends of the steel plate 20 are held between the holding tools 21 and 21. At this time, the steel plate holding mechanism 31 + 21 + 32 is inclined in the same manner as the tilt table 34, but the tilt angle θ is not so large. Therefore, the setting work of the steel plate 20 including the loose insertion into the inductor 22 is performed in this tilt position. Even with tilting, it can be done easily, just as in horizontal movement.
Then, the steel plate holding mechanism 31 + 21 + 32 holding the steel plate 20 is moved to the high position side of the tilting table 34 (see FIG. 1C), and preparation for heat treatment is completed.

  When automatic control of the heat treatment process is started by the control device, high-frequency energization from the high-frequency power supply device to the inductor 22 is performed, the facing portion of the steel plate 20 is rapidly induction-heated, and the movable frame 31 is inclined. The steel plate 20 is moved at a constant speed obliquely downward along the table 34 so that the rapid heating portion of the steel plate 20 moves from one end to the other end, and further, water is supplied from the water cooling device to the water discharge unit 23 and the steel plate 20 is discharged from the water discharge unit 23. Cooling water is sprayed onto the steel plate 20, and the rapid heating portion of the steel plate 20 is rapidly cooled by the water discharge cooling. At that time (see FIG. 2B), the angle θ of the upper surface of the steel plate 20 is added to the water discharge angle η from the water discharge portion 23 to the upper surface of the steel plate 20, and the water discharge angle (η + θ) with respect to the horizontal is the angle η during horizontal installation. Furthermore, since the position directly under the water discharge part (D) and the position directly under the inductor (C) are higher than the water landing position on the upper surface of the steel plate 20, the water discharge part of the cooling water 24 and The amount of unwanted entry into the inductor is very small.

  Moreover, since the water discharge by this water discharge part 23 starts near the clamping tool 21, it switches to high speed and multistage by control of the electromagnetic switching valves 41-46, and at the beginning, the amount of water discharge is restrained small and it increases rapidly. The Therefore, even if the holding tool 21 is near the water discharge destination, the amount of water stored therein is very small at first, and when the amount of stored water increases, the holding tool 21 moves away by the movement of the movable frame 31 and the steel plate 20. There is also an effect that the holding tool 21 is positioned relatively lower than the water discharger 23 according to the inclination of the steel plate 20 based on the inclination of the inclined table 34 and the amount of movement, and the water storage by the holding tool 21 is the water discharger. Therefore, the induction heating width C and the high temperature maintenance width D related to the heat treatment part of the steel plate 20 are stably secured.

  As the movement of the movable frame 31 proceeds (see FIG. 1 (d)), one end of the steel plate 20 is separated from the water discharge portion 23, so that there is an effect of the inclination of the inclined base 34 and the inclination of the steel plate 20, and Therefore, the water discharge amount of the water discharge part 23 is kept constant. Also at this time (see FIG. 2 (c)), the water discharge angle from the water discharge portion 23 to the horizontal surface of the steel plate 20 is added to the angle θ of water discharge from the water discharge portion 23 to the upper surface of the steel plate 20, thereby increasing the water discharge angle (η + θ) with respect to the horizontal. In addition, since the position directly below the water discharge part and the position directly below the inductor are higher than the water landing position on the upper surface of the steel plate 20, the cooling water 24 is undesirably moved toward the water discharge part and the inductor. Since the advantage that the amount of entering is small is maintained, the induction heating width C and the high temperature maintenance width D are stably secured even if the steel plate 20 is a thin plate.

When the movement of the movable frame 31 further proceeds (see FIG. 1 (e)) and the other end of the steel plate 20 is closest to the inductor 22, energization to the inductor 22 is stopped, and then the water discharge of the water discharge section 23 is stopped. As a result, the first heat treatment is completed.
Then, the movement of the movable frame 31 also stops, and further, the movable frame 31 is reversed and the steel plate 20 returns to the initial position together with the movable frame 31. Since the heat treatment is not performed in this return, the return movement is performed at a high speed in order to shorten the return time.

Although the detailed description which is repeated is omitted, the above-described processing is repeated according to the parameter setting, so that rapid heating by induction heating and rapid cooling by water discharge are necessary for crystal grain refinement while moving the steel plate 20 in the longitudinal direction. Only, the crystal grains of the steel sheet 20 are refined.
In this way, when the desired heat treatment is completed and the temperature of the steel plate 20 is lowered, the treated steel plate 20 is removed from the steel plate heat treatment apparatus 30, but the work is also inclined tilting because the inclination angle θ is not so large. However, it can be done easily just as in horizontal movement.

  About Example 2 of the steel plate heat processing apparatus of this invention, the specific structure is demonstrated referring drawings. 3A and 3C are front views of the steel plate heat treatment apparatus 60.

This steel plate heat treatment apparatus 60 is different from the steel plate heat treatment apparatus 30 of the first embodiment described above in that the inclined base 34 swings and the heights of both ends can be alternately changed, and the water discharge section 23 is The point is that one is added and distributed on both sides of the inductor 22.
One of the programs of the control device is such that the water discharge from the two water discharge sections 23 is not performed from the diagonally upper part of the inductor 22 but only from the diagonally lower part of the inductor 22. Department has been changed.

  In order to swing the tilting table 34, instead of the above-described fixed leg 35, a longer but fixed-length leg 61 is adopted, and a bearing or the like at the top of the leg 61 is used as the tilting table 34. Is supported so as to be bi-directionally rotatable in the center in the longitudinal direction. Further, instead of the above-described extendable / contractible leg portion 36, a variable length leg portion 62 having an expanded expansion / contraction range is adopted, and the leg portion 62 extends and contracts while supporting the end portion of the inclined base 34. The tilt table 34 swings so that the heights at both ends thereof are alternately switched. Furthermore, the tilt angle θ of the tilt base 34 can be set to take any two positions within a range of −20 ° to + 20 °, for example, by a lock mechanism (not shown) attached to the leg portion 62.

In this steel plate heat treatment apparatus 60, setting of the steel plate 20 and the like are easily performed in the same manner as in the above-described steel plate heat treatment apparatus 30, and the first heat treatment is performed with the legs 62 extended, for example (see FIG. 3A). The movement of the movable frame 31, the energization of the inductor 22, and the water discharge of the water discharge portion 23 obliquely below (to the left) are performed stably in the same manner as in the steel plate heat treatment apparatus 30 described above.
However (see FIG. 3B), after the first heat treatment, the movable frame 31 does not return, but the leg portion 62 contracts, for example, and the tilting table 34 swings. Are replaced, and the water discharge portion 23 obliquely below the inductor 22 is changed from the left side to the right side.

Then (see FIG. 3 (c)), except for left-right reversal, the second heat treatment is the same as the first heat treatment, and the movable frame 31 is moved, the inductor 22 is energized, and the water is discharged obliquely below (but to the right). It is also performed stably by the water discharge of the part 23.
In this way, the heat treatment for two times is completed, but the temporary suspension time of the heat treatment in the meantime is shortened from the return time of the movable frame 31 to the swing time of the tilting table 34, and thus the total time required for the heat treatment is shortened accordingly. Will be.
Similarly, the heat treatment is repeated as many times as necessary to complete the grain refinement of the steel sheet 20, but the set-up operation is performed only once, whereas the above-mentioned time reduction is made every time the heat treatment is repeated. Therefore, the shorter the heat treatment, the more pronounced the shortening effect.

[Others]
In the above embodiment, the water receiver 37 is attached to the inclined base 34 supported by the legs 35 + 36 and 61 + 62. However, if the water receiver 37 has sufficient strength and rigidity, the water receiver 37 is attached to the leg. 35 + 36 and 61 + 62 may be supported, and the tilt base 34 may be mounted on the water receiver 37.
In the said Example, although the multistage switching which concerns on the water discharge of the water discharge part 23 was 3 steps | paragraphs, the water discharge of the water discharge part 23 may be switched by what steps, and may be made to be continuously variable.
In the second embodiment, the extendable leg portion 62 is provided only at one end of the tilt base 34. However, the extendable leg portion 62 is provided at both ends of the tilt base 34 so as to be alternately extended and contracted. In this case, the fixed-length legs 61 may be omitted.

  The steel plate heat treatment apparatus of the present invention is not limited to the application to thin finite-length steel plates, and it is close to a thick plate or thick as long as it is held by clamping at both ends and an appropriate tensile force is applied. It is applicable also to the finite length steel plate which belongs to a board.

About Example 1 of this invention, the structure of a steel plate heat processing apparatus is shown, (a) is a top view of a steel plate holding | maintenance mechanism, (b) is a front view of the apparatus which removed the water receiver, (c)-(e). Both are front views of the apparatus. (A) is a symbol figure which shows the structure of the water supply circuit with variable cooling water quantity, (b)-(c) are all the longitudinal cross-sectional enlarged views of the heat processing part. About Example 2 of this invention, the structure of a steel plate heat processing apparatus is shown, (a)-(c) are all front views. The subject of this invention is illustrated, (a) is a top view in which the thick plate is placed and moved by heating, (b) is the front view, and (c) is moved and heated by placing the thin plate horizontally. (D) is the front view, (e) is the longitudinal cross-sectional enlarged view of AA arrow which concerns on a thick board, (f) is the longitudinal cross-sectional enlarged view of BB arrow which concerns on a thin board.

Explanation of symbols

10 ... steel plate (thick plate), 11 ... tension restraint, 12 ... bearing
13 ... Inductor, 14 ... Water discharge part, 15 ... Cooling water,
20 ... steel plate (thin plate), 21 ... clamping device,
22 ... Inductor, 23 ... Water discharge part, 24 ... Cooling water,
30 ... Steel plate heat treatment apparatus, 31 ... Movable frame, 32 ... Tensile force imparting member,
34 ... tilting table, 35, 36 ... legs, 37 ... water receiver,
41-46 ... electromagnetic switching valve, 51-56 ... variable throttle valve,
60 ... Steel plate heat treatment device, 61, 62 ... Legs

Claims (3)

  In order to carry out the grain refinement treatment by repeatedly applying a heat treatment that applies rapid heating and subsequent quenching to the steel sheet, the steel sheet is moved in the longitudinal direction while the steel sheet is sequentially subjected to induction heating and subsequent water cooling. In the steel plate heat treatment apparatus to be applied, a holding mechanism that holds both ends in the longitudinal direction of the steel plate over the entire width and pulls the steel plate in the longitudinal direction, and a posture that is horizontal in the width direction and inclined in the longitudinal direction. The holding mechanism is mounted in such a manner that the steel plate is moved in a longitudinal direction by linearly moving the holding mechanism, and the tilting table is mounted on the tilting table and held by the holding mechanism. An inductor for rapid heating arranged so as to face the entire section in the width direction and partly in the longitudinal direction with respect to the steel sheet, and is mounted on the tilting table next to or near the inductor. Said steel plate Steel heat treatment apparatus in the width direction against, characterized in that a water discharge portion for quenching arranged so as to face a portion in the longitudinal direction over the entire section.   The water supply circuit for supplying cooling water to the water discharge unit varies the amount of water supply, so that when the water discharge unit starts water discharge near the holding tool, the water discharge amount of the water discharge unit is reduced, and the water discharge unit However, the water discharge amount of the water discharge portion increases as the distance from the holding tool increases, and the water discharge amount of the water discharge portion is maintained constant after the water discharge portion leaves the holding tool. The steel plate heat treatment apparatus according to claim 1.   The said water discharge part is provided in the both sides of the said inductor, The said inclination stand rock | fluctuates, and the height of both ends can be changed alternately, The Claim 1 or Claim 2 characterized by the above-mentioned. Steel plate heat treatment equipment.

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