JPS59232217A - Method for subjecting work of ununiform thickness to high frequency induction heating simultaneously - Google Patents

Abstract

PURPOSE:To heat-treat efficiently the thin and thick parts of a work simultaneously and to improve the productivity by subjecting the thin and thick parts to induction heating under conditions during the induction heating of the thick part while cooling the thin part with a cooling medium. CONSTITUTION:A work W is placed so that the thin part 2 is positioned under the thick part 1. A work coil 11 for the thick part and a work coil 21 for the thin part are connected to a high frequency output transformer T, and the coils 11, 21 are set opposite to the parts 1, 2, respectively. Electricity required to carry out the surface hardening of the thick part 1 is supplied to the coils 11, 12, and a cooling medium 3 is continuously fed to the thin part 2 to prevent excessive hardening. Thus, the parts 2, 1 are efficiently heat-treated simultaneously and the productivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for simultaneously high-frequency induction heating workpieces having different thicknesses by means of a connected body of workpiece coils corresponding to each workpiece.

When surface hardening thick and thin parts of a workpiece using high-frequency induction heating, the mass effect of heating in each part is different, so in the past, separate induction heating was performed economically. (So-called two-stage quenching: quenching over two steps), resulting in poor productivity, and it has been desired to implement simultaneous surface quenching. In response to this, attempts have been made to heat a thick-walled work coil and a thin-walled work coil by connecting them to one high-frequency output transformer, but in this case, since the output source is the same, heating is possible. The time is also the same, so the only way to achieve a unique heating effect for thick or thin parts is to adjust the distance between each work coil and the workpiece, and this decision is left to advanced empirical rules. For non-mass production purposes, for example, if the distance adjustment on the thin-walled part side is incorrect, the thin-walled part may burn out (unnecessary deep penetration may occur... etc.

The present invention eliminates the above-mentioned problems, and although the coil for thin-walled portions and the coil for thick-walled portions are connected and induction heated at the same time using appropriate power for the same heating time, the coils for thin-walled portions and thick-walled portions are heated at the same time. Continuously apply cooling water, liquid, etc. to the surface opposite to the surface hardening surface of the thin wall part in parallel with induction heating to receive excess heating due to thermal energy and mass effect. The main idea is to prevent this by recognizing what to do. According to the present invention, there is no need to make delicate distance adjustments between the thin-walled workpiece and the coil, and only a rough distance setting is required. It is noteworthy that the damage does not spread to the thick walled parts. The present invention will be explained in detail below using detailed practical examples. The drawings are sectional explanatory views of essential parts of an apparatus for carrying out the present invention. According to the present invention, J, IF of the workpiece W
, Regarding internal part 1 and thin part 2 and 2 madder frequency induction heating,
Holding the thin part 2 below the thick part 1, the work coil 11 for the thick part and the work coil 21' for the thin part in one high frequency quadrance T! The work coil 11 for the thick part is placed opposite to the thick part 1 and the work coil 21 for the thin part is placed opposite to the thin part 2, and the desired depth of the thick part 1 is set. Apply heating power and heating time commensurate with surface hardening 12 to both coils 11 and 21, respectively, and continuously apply cooling mode 3 to the surface hardened 22 surface and the opposite surface of t to the thin wall portion 2. Excessive N in the thin wall portion 2
This is a method of simultaneous high-frequency induction heating of workpieces with different wall thicknesses. In the case of the figure, thick part 1
and the thin wall portion 2 correspond one to one, and the surface hardening 22 of the thin wall portion 2 is performed.
An example is shown in which is the inner peripheral surface of the workpiece W. Reference numeral 31 indicates a jacket for the cooling type 3 (water in this case), and 32 indicates an outlet thereof.

The distance d1 between the thick section work coil 11 and the thick section 1 is small, and the distance d2 between the thin section work coil 21 and the thin section 2 is a dog, and the heating power supplied to both coils 11 and 21 is small. The heating time is to heat the thick part 110 surface hardening 12 to the above distance d.
The outer periphery of the thin-walled portion 2 of the cooling mode 3 is set to a thin value as appropriate so that it can be performed with a distance of i. Whether the coils 11 and 21 are connected in series or in parallel to the high-frequency quadrangle T is determined as appropriate based on the heating power and the coil shape.

The coil shape is appropriately selected depending on the shape of the workpiece W, such as a loop type or a semi-loose type. Examples of the present invention are listed below.

(Example) (a) Workpiece: A hollow spindle made of 8450 with a step on the inner periphery, the outer diameter of the thick part is 100φ, and the wall thickness is 8MM.

The outer diameter of the thin wall part is 92φ, and the wall thickness is 4 gates.

(b) Work coil: Loop-type coils for both thick and thin parts were connected in series to the transformer.

The distance d1 is 1.5 mm, d2 is l, 5 mm.

(0 heating tea...Heating power 2-3 K-W/ly!,
Heating time is 4-5 times.

(d) External cooling condition -0.5~1.0 (1/min
The cooling time started at the same time as the initiation of induction heating and continued for about 10 SeC at a liquid volume of /1 yre.

(e) Cooling conditions for quenching...quenching liquid at 1.0~20eΔ
It was applied immediately after the induction heating was stopped in an amount of 1/2.

(f″) Surface hardening depth: 2 thick parts, 2 thin parts (
Incidentally, the charring did not penetrate into other parts of the thin-walled part. ) As described above, the present invention can prevent conduction in thick portions α! Even if the thin-walled part is simultaneously induction-heated according to the thin-walled part, by continuously applying cooling to the surface opposite to the surface-hardened surface of the thin-walled part and cooling the thin-walled part, unnecessary range of hardening can be caused in the thin-walled part. without giving any input,
Both parts can be efficiently heated at the same time, the thin part is kept below the thick part and cooling is applied, so the cooling does not interfere with the heating of the thick part, and the cooling medium is By appropriately selecting application conditions, strict consideration cannot be given to setting the distance between the thin-walled work coil and the thin-walled portion.

In addition, instead of what is shown in the example, the surface hardening of the thin-walled part and the thick-walled part can be applied to the outer periphery of the workpiece, and the coolant can be applied to the inner periphery of the thin-walled part, and two or more thick-walled parts.

Induction heating over the thin wall portion, connection of the coil and transformer in parallel, etc. may also be freely adopted in accordance with the idea of the present invention.

[Brief explanation of drawings]

The drawing is an explanatory cross-sectional view of a main part of an apparatus embodying the present invention. (Explanation of symbols) 21... Work coil for thin-walled part, 22... Layout for thin-walled part, 3... Cooling medium, 31... Jacket for cooling medium, 32... Outlet. One or more -

Claims (1)

[Scope of Claims] 1. Holding the thin and thick portions below the thick and thin portions of the workpiece during high-frequency induction heating;
A work coil for a thick wall portion and a work coil for a thin wall portion are connected to one high frequency output transformer, and the work coil for a thick wall portion is connected to the thick wall portion, and the work coil for a thin wall portion is connected to the thin wall portion. The heating power and heating time corresponding to the surface hardening of the desired depth of the thick wall part are applied to both coils respectively, and the cooling medium is continuously applied to the opposite side of the surface hardening surface for the thin wall part. A method of simultaneously applying high-frequency induction heating to workpieces having different wall thicknesses by applying heat to suppress excessive surface hardening of the thin-walled portion. 2. The method according to claim 1, wherein the surface-hardened surface of the thin-walled portion is the outer circumferential surface of the workpiece, and the coolant application surface is the four circumferential surfaces of the workpiece. 3. The method according to claim 1, wherein the surface-hardened surface of the thin-walled portion is the inner circumferential surface of the workpiece, and the coolant application surface is the outer circumferential surface of the workpiece.