JPH03274221A - Method and apparatus for high-frequency shifting quenching and tempering - Google Patents

Abstract

PURPOSE:To execute quenching and tempering to a long-sized steel product with simple apparatus at a low cost by executing high-frequency induction heating while shifting the long-sized steel product, the quenching with cooling liquid injection and the tempering with the high-frequency induction heating and further, executing after-cooling with the cooling liquid. CONSTITUTION:The long steel product 1 of ball screw, etc., is shifted to the arrow mark A direction while rotating around the center axis. At first, after heating the steel product 1 to the quenching temp. with the induction heating coil 10 of a truncated-form semi-opening type high-frequency quenching with length L1, by spraying rapid cooling liquid (l1) from a rapid cooling liquid injection jacket 20, the rapid cooled quenching is executed. Successively, after removing the cooling liquid (l1) for quenching by injecting compressed air K from an air nozzle 50, the electric current is conducted to a high-frequency tempering coil 30 having length L2 longer than 1.5XL1, and heating for tempering are executed with this induction current, and at last, the steel product is cooled to room temp. by injecting the cooling liquid (l2) through jackets 40a-40c from three ways.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an induction hardening and tempering method and apparatus capable of performing induction hardening and induction tempering subsequent to induction hardening.

<Conventional technology> Conventionally, when a workpiece is hardened by induction hardening, tempering after quenching is carried out by transporting the workpiece into an electric furnace separate from the equipment that performed induction hardening. ing.

<Problems to be Solved by the Invention> Therefore, not only is it time consuming to store 10 tons of workpieces and then move them to the electric furnace for tempering, but also the tempering process is intermittent with continuous hardening work. For connection with
This resulted in unnecessary loss of time and space, and required a large cost to install an electric furnace.

The present invention was devised in view of the above circumstances, and when hardening and tempering a long workpiece, it does not require an electric furnace for tempering, and the hardening and tempering can be performed simultaneously. It is an object of the present invention to provide a method and apparatus for high-frequency transfer quenching and tempering, which can perform tempering at low cost as a continuous operation.

Means for Solving the Problems> In order to solve the above problems, the high-frequency moving quenching and tempering method of the present invention provides a method for high-frequency moving quenching and tempering of a long workpiece after high-frequency heating while moving the long workpiece in the longitudinal direction of the workpiece. The workpiece is hardened by injecting a quenching liquid into the workpiece, and then the workpiece is tempered by high-frequency heating.

In addition, in order to solve the above problem, the high-frequency moving quenching and tempering apparatus of the present invention provides a high-frequency moving quenching and tempering device that performs induction hardening and induction tempering on a long workpiece while moving the workpiece in the longitudinal direction of the workpiece. A quenching and tempering device, and
A saddle-shaped semi-open type induction hardening heating coil that heats the workpiece for induction hardening, and an induction hardening heating coil that cools and hardens the heated workpiece on the side in the direction of movement of the workpiece. A quenching liquid injection jacket provided, an induction tempering coil placed on the same axis for heating and tempering the hardened workpiece, and a cooling for aftercooling the workpiece placed on the same axis. Equipped with a liquid jet jacket.

It is effective to make the length of the induction tempering coil in the longitudinal direction of the workpiece longer than the length of the induction hardening heating coil in the longitudinal direction of the workpiece.

Further, it is preferable that the length of the induction tempering coil in the longitudinal direction of the workpiece is 1.5 times or more the length of the induction hardening heating coil in the longitudinal direction of the workpiece.

Preferably, the aftercooling cooling liquid injection jacket is composed of one jacket provided above the workpiece and a pair of jackets provided oppositely on both sides below the workpiece.

<Function> While moving a long workpiece in the longitudinal direction of the workpiece, the workpiece is heated with high frequency, then a quenching liquid is injected onto the workpiece to harden it, and then the workpiece is heated with high frequency to temper it. After-cooling the workpiece by injecting cooling liquid onto the workpiece.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 5 are drawings for explaining an embodiment of the high frequency moving quenching and tempering method of the present invention and an embodiment of the high frequency moving quenching and tempering apparatus for realizing this embodiment. Figure 1 is a schematic configuration diagram of the high frequency moving quenching and tempering equipment, and Figure 2 is a schematic diagram of the high frequency moving quenching and tempering equipment.
The figure is a graph showing the relationship between the temperature of the ball screw that is hardened and tempered by this high-frequency moving quenching and tempering device and the distance traveled by the ball screw. Figure 3 shows the temporal change in temperature after the ball screw has been tempered. FIG. 4 is an explanatory diagram of a coolant injection jacket for aftercooling, and FIG. 5 is an enlarged partial sectional view of a ball screw.

As shown in FIG. 1, the high frequency moving quenching and tempering apparatus of this embodiment uses a long ball screw 1 as a workpiece. The ball screw 1 is provided with a spiral groove 2 through which balls (not shown) are transferred. This high-frequency moving hardening and tempering device performs high-frequency hardening after high-frequency hardening while moving the ball screw 1 in its longitudinal direction (in the direction of arrow A) and rotating the ball screw 1 about its longitudinal axis. This is an induction hardening and tempering device that performs resetting, and includes a saddle-shaped semi-open induction hardening heating coil 10 that heats the ball screw 1 for induction hardening, and a quenching liquid that cools the heated ball screw 1. A quenching liquid injection jacket 20 is provided on the moving direction side of the ball screw 1 of the induction hardening heating coil 10 in order to inject the ball screw 1, and a quenching liquid injection jacket 20 is provided on the side of the ball screw 1 in the moving direction of the ball screw 1 in order to inject the ball screw 1.
A saddle-shaped semi-open high-frequency tempering coil 30 provided on the moving direction side and a cooling liquid 1 that cools the tempered ball screw 1 to room temperature! A cooling liquid injection jacket 40 for aftercooling is provided on the side of the induction tempering coil 30 in the direction of movement of the ball screw 1 in order to inject it. Reference numerals 100 and 101 are high-frequency power sources that feed power to the induction hardening heating coil 10 and the induction tempering coil 30, respectively. In this embodiment, high frequency power supplies 100 and 101
Although it is a separate power source from the
The induction tempering coil 30 may be powered through a suitable impedance.

In FIG. 1, the lengths of the heating portions of the induction hardening heating coil 10 and the induction tempering coil are shown.

And between L2, L! L and L2 are chosen to be >1.5 XLI. Note that 50 is an air nozzle that blows out compressed air k to blow away the quenching liquid 11 adhering to the surface of the ball screw 1. Further, the aftercooling coolant injection jacket 40 includes three jackets 40a, 40b, and 4, as shown in FIG.
The jacket 40a is arranged above the ball screw 1, and the jackets 40b and 40C are arranged slightly below both sides of the ball screw 1 toward the ball screw 1. In this way, three jackets 40a, 40
When jackets b and 40c are arranged, the amount of cooling liquid 422m injected by jacket 40a is equal to the amount of cooling liquid j2zb injected by jackets 40b and 40c, respectively.
, j22c, the entire surface of the ball screw 1 is uniformly cooled. Furthermore, the number of jackets that can uniformly cool the surface of the ball screw 1 can be minimized.

During hardening and tempering of the ball screw 1, as shown in FIG.
Three points were selected: and point C.

Point A is a point near the intersection of groove 2 and the outermost surface of ball screw 1, point B is a point directly below the center bottom of groove 2, and point C is near the surface midway between grooves 2 of ball screw 1. It is a point.

Next, the operation of the high frequency moving quenching and tempering apparatus of this embodiment will be explained. The ball screw 1 is rotated about a longitudinal axis by a work rotating device (not shown). Heating coil 1o for induction hardening and induction tempering coil 30
A high frequency current is applied from a high frequency power source (not shown), and the quenching liquid 11 is injected from the quenching liquid injection jacket 20 and the cooling liquid 12 is injected from the cooling liquid injection jacket 40.

The ball screw 1 is moved in the direction of arrow A by a moving device (not shown). The surface of the ball screw 1 is heated by the induction hardening heating coil 1o. When the heated surface moves in the direction of arrow A, it is cooled and hardened by the quenching liquid 1° injected from the quenching liquid injection jacket 20, and the desired depth and hardness are maintained on the surface of the ball screw 1. A hardened layer is formed. The coolant 11 adhering to the surface of the ball screw 1 is blown away by the compressed air k blown out from the air nozzle 50. When the hardened surface further moves in the direction of arrow A, it is heated and tempered by the induction tempering coil 30. When the tempered surface continues to move in the direction of arrow A, it is uniformly cooled to approximately room temperature by the coolant 12 injected from the aftercooling coolant injection jacket 40.

Figure 2 is a graph showing how the temperature at point C of the ball screw 1 changes due to the above operation.
The diagram will be explained. P, -P.

is a point provided on the graph for the convenience of explaining the change in temperature state at point C.

The point C of the ball screw 1 is at about room temperature (for example, 20°C
) is heated by the induction hardening heating coil 10 and the temperature is raised to 850-900°C (pz
point). At this time, the magnitude of the electric power applied to the heating coil 10 for induction hardening is 2 to 4 kW/cm2 (however, kW/cm2 is covered by the heating coil 10 for induction hardening, depending on the size of the ball screw 1). power per 1 cm of surface area over the entire circumference of the ball screw 1), and the frequency is 60 to 400 kHz.
It is. Then, the temperature increases at a rate of 100 to 200°C/sec. Next, the quenching liquid is injected from the quenching liquid injection jacket 20 onto the heated surface of the ball screw 1.
The surface is cooled and hardening is completed (43 points). Then,
The hardened surface is heated and tempered by the induction tempering coil 30. That is, the hardened surface is heated to approximately 150-200°C (14 points).

And this surface is still high frequency tempered coil 30
(between point P and point 43), but in this embodiment, the shape of the induction tempering coil 30 is appropriately selected, and the temperature is maintained by the induction tempering coil 30 during this passage. It is like that.

At this time, the magnitude and frequency of the electric power applied to the induction tempering coil 30 are 0.01 to 0.1 kW/cm2 and 60 to 400 kHz, respectively, depending on the size of the ball screw 1. And 7-20'C
The temperature rises in /second. That is, the induction tempering coil 3
The length of the ball screw 1 in the longitudinal direction is 1 as described above compared to the length of the induction hardening heating coil 10 in this direction.
．． The length is more than 5 times longer, and the electric power applied to the induction tempering coil 30 is smaller than the electric power applied to the induction hardening heating coil 10, so that the temperature rise of the ball screw 1 during tempering is reduced. The degree of temperature rise is small compared to the degree of temperature rise during quenching. That is, the hardened ball screw 1
By slowly heating the ball screw 1, the ball screw 1 can be effectively tempered. In addition, the fact that the electric power for tempering is smaller than the electric power for quenching as mentioned above means that the penetration depth of the induced current is shallow (about 1/10 of that during quenching).
Therefore, by slowly heating the ball screw 1 as described above, effective tempering can be performed using conductive heat.

When the vicinity of the surface to be tempered finishes passing under the high-frequency tempering coil 30 (PS point), it enters a state of natural cooling (
After that, the coolant 12 is injected from the aftercooling coolant injection jacket 40, and the tempered surface of the ball screw 1 is brought to approximately room temperature (for example, 40"C) (P, point).

FIG. 2 is a graph regarding the temperature at point C of the ball screw 1, while FIG. 3 is a graph showing temperature changes at points A, B, and C of the ball screw 1 after passing through the induction hardening heating coil 10. As shown in the graph of Fig. 3, the induction hardening heating coil lO is turned on at the moment (tl) when the ball screw 1 comes out.
Then, the temperatures at points A, B, and C are at point PX3, point PX11, and point PZC, respectively, and from then on, the temperatures of quenching liquid l,
Heat soaking is promoted until time t2 when is injected, resulting in the p'za point, the P'211 point, and the p'zc point, respectively, at which point the quenching liquid 11 is injected to reach the 28 point.

At point 14 during tempering, the heating power was low and the heating time was long (L2/L1 times), so it can be said that there is almost no change. Thereafter, the coolant 12 is injected from the aftercooling coolant injection jacket 40 to reach point 27, which is approximately room temperature.

<Effects of the Invention> As explained above, the induction hardening and tempering method and apparatus of the present invention rapidly cools the long workpiece after being heated for induction hardening while moving the long workpiece in the longitudinal direction of the workpiece. Hardening is performed by injecting a liquid, and then the workpiece is tempered by high-frequency heating.

After tempering, after-cooling is performed by spraying a cooling liquid onto the workpiece to bring it to room temperature.

Therefore, according to the high frequency moving quenching and tempering method and apparatus of the present invention, an electric furnace for tempering is not required when quenching and tempering a long workpiece, and therefore,
There is no need to move the workpiece to an electric furnace after quenching, so there is no cost to install an electric furnace, and tempering can be performed on the same line as quenching, making tempering inexpensive. It has the advantage of being able to

[Brief explanation of drawings]

1 to 5 are drawings for explaining an embodiment of the high frequency moving quenching and tempering method of the present invention and an embodiment of the high frequency moving quenching and tempering apparatus for realizing this embodiment. , Figure 1 is a schematic diagram of the high-frequency moving quenching and tempering equipment.
Figure 2 is a graph showing the relationship between the temperature of the ball screw that is quenched and tempered by this high-frequency moving quenching and tempering device and the distance traveled by the ball screw, and Figure 3 is a graph showing the relationship between each part of the ball screw after it has been heated for quenching. FIG. 4 is an explanatory diagram of a coolant injection jacket for aftercooling, and FIG. 5 is an enlarged partial sectional view of a ball screw. 1... Workpiece, 10... Heating coil for induction hardening,
20... Quenching liquid injection jacket, 30... Induction tempering coil, 40... Cooling liquid injection jacket, 40
a, 40b140c...jacket, 11...quenching liquid, 1 g, Las 12Zbs j2Zc"
'Cooling liquid.

Claims (5)

[Claims] (1) While moving a long workpiece in the longitudinal direction of the workpiece, the workpiece is heated at high frequency, then a quenching liquid is injected onto the workpiece to harden it, and then the workpiece is heated at high frequency to temper it. High frequency transfer quenching and tempering method. (2) A high-frequency moving quenching and tempering device that performs induction hardening and induction tempering on a long workpiece while moving the workpiece in the longitudinal direction of the workpiece; a saddle-shaped semi-open induction hardening heating coil for heating; a quenching liquid injection jacket provided on the side of the induction hardening heating coil in the direction of movement of the workpiece for cooling and hardening the heated workpiece; Equipped with an induction tempering coil that is continuously provided on the same axis for heating and tempering the hardened workpiece, and a cooling liquid injection jacket that is further provided on the same axis for after-cooling the workpiece. A high frequency moving quenching and tempering device featuring: (3) The induction hardening and tempering apparatus according to claim 2, wherein the length of the induction tempering coil in the longitudinal direction of the workpiece is longer than the length of the induction hardening heating coil in the longitudinal direction of the workpiece. (4) The induction tempering device according to claim 2, wherein the length of the induction tempering coil in the longitudinal direction of the workpiece is 1.5 times or more the length of the induction hardening heating coil in the longitudinal direction of the workpiece. . (5) Coolant injection jacket for aftercooling:
3. The induction quenching and tempering apparatus according to claim 2, comprising one jacket provided above the workpiece and a pair of jackets provided oppositely on both sides below the workpiece.