JPH0488119A - Remelting hardening method and device thereof - Google Patents

Abstract

PURPOSE:To finish all works to a uniform hardness by measuring the carbon content of the works before irradiating the surfaces to be treated of the works with energy beams and controlling the irradiation output of energy beams so as to form necessary hardened layers on the surfaces to be hardened of the works according to the measured contents. CONSTITUTION:Cam surfaces 22' to 24' of respective cams 21 to 24 of a cam shaft 2 are remelted and hardened by the energy beams X projected from respective beam torches 4, 4. The carbon content of the cam shaft 2 is measured by a measuring instrument 3 before the respective cam surfaces 22' to 24' are irradiated with the energy beams X. The irradiation output of the energy beams X are then so controlled that the necessary hardened layers are formed on the respective cam surfaces 22' to 24' according to this content. The respective cam surfaces 22' to 24' are respectively uniformly chilled and the necessary hardened layers are formed thereon in this way even if the carbon content varies with each of the cam shafts 2. All the cam shafts 2 are thus finished to the uniform hardness.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a method of hardening a chain by irradiating an energy beam onto the surface of a workpiece to be hardened, for example, the surface of a cam in a camshaft that constitutes a valve mechanism of an engine. The present invention relates to a method and apparatus for remelting and hardening.

(Prior art) For example, for metal parts that require particularly wear resistance, such as the camshaft that constitutes the valve mechanism of an engine,
The surface may be hardened.

As a surface hardening method for metal parts such as the camshaft, for example, as disclosed in Japanese Patent Application Laid-open No. 60-258421, an energy beam (plasma arc) is irradiated onto the surface of the metal workpiece to be hardened. A so-called remelting hardening method is known in which the surface layer of the chain is locally remelted to chill the structure and increase the hardness of the chain.

(Problems to be Solved by the Invention) By the way, the molten state of the surface to be hardened in the metal workpiece that is remelted by the remelting hardening method as described above is as follows.
Of the chemical components contained in the workpiece, it is particularly influenced by the carbon content, and the state of formation of the chill layer formed by solidification of this licked and remelted structure is greatly affected by the difference in the carbon content of each workpiece. It was supposed to change.

On the other hand, camshafts, which are an example of a workpiece to be hardened by the above-mentioned remelting hardening method, are generally manufactured by casting, and each camshaft usually has a slightly different carbon content. For this reason, when attempting to remelt and harden the cam surface of a camshaft and irradiating the surface with an energy beam at a uniform irradiation output, the melting state of each camshaft will vary due to the difference in carbon content. Therefore, variations occur in the state of formation of the chill layer, and the hardness of the cam surface differs for each camshaft, making it difficult to make the quality constant for all camshafts.

Therefore, the present invention aims to remelt and harden the face portion of a metal workpiece such as the camshaft by irradiating an energy beam onto the surface to be hardened, without being affected by the difference in the carbon content of each workpiece. It is an object of the present invention to provide a remelting hardening method capable of uniformly forming a required chill layer on all workpieces, and an apparatus for carrying out the method.

(Means for Solving the Problems) In order to solve the above problems, the present invention is characterized by the following configuration.

First, the invention according to the first claim of the present application (hereinafter referred to as the first invention) provides a method for remelting and hardening the surface to be hardened by irradiating the surface to be hardened of a work with an energy beam. At least the carbon content in the workpiece is measured before irradiation with the beam, and the irradiation output of the energy beam is controlled according to the carbon content so that a required hardened layer is formed on the surface of the workpiece to be hardened. It is characterized by what it did.

Further, the invention according to the second claim of the present application (hereinafter referred to as the second invention) is an apparatus for carrying out the method of the first invention, which is an energy beam irradiation device for irradiating an energy beam onto a surface to be hardened of a workpiece. a detection means for detecting at least the carbon content in the work before irradiation with the energy beam by the irradiation means; and a detection means for detecting at least the carbon content in the workpiece before irradiation with the energy beam by the irradiation means; The present invention is characterized by further comprising a control means for controlling the irradiation output of the energy beam so that a layer is formed.

(Function) According to the first and second inventions, at least the carbon content in the workpiece is measured before the energy beam is irradiated onto the surface of the workpiece to be hardened, and the carbon content of the workpiece is determined according to the content. The irradiation output of the energy beam is controlled so that the required hardened layer is formed on the hardened surface. Even if the hardening process surface of each workpiece is uniformly chilled and the required hardened layer is formed on the face part, all the workpieces can be finished with uniform hardness.

Example) Examples of the present invention will be described below.

First, the remelting hardening method according to the first invention will be explained. In this method, when remelting and hardening the face by irradiating the surface of the metal workpiece to be hardened with an energy beam, Measure at least the carbon content in the workpiece before irradiating the hardening surface, and control the irradiation output of the energy beam according to the measured value so that the required hardening layer is formed on the hardening surface of the workpiece. It was designed to do so. An example of a work that is hardened by the remelting hardening method is a camshaft that constitutes a valve mechanism of an engine in an automobile.In this example, the surface of the cam of the camshaft is hardened. Let's explain the case.

Next, referring to FIG. 1, a description will be given of an apparatus for hardening the cam surface of a camshaft by the above remelting hardening method. a measuring device 3 for measuring the carbon content of the camshaft 2, and each cam 2 of the camshaft 2], 22.2
3.24, an energy source 5.5 for supplying energy to each of these beam torches 4, 4 to generate an energy beam; The controller 6 has a controller 6 that controls the amount of energy supplied from the beam torches 5 and the output of the energy beam irradiated from each beam torch 4, and a main controller 7 that controls the controller 6.

A signal a indicating the carbon content of the camshaft 2 from the measuring device 3 is inputted to the main controller 7, and based on this, the main controller 7 sends the signal a to the controller 6.
A signal is output. And in the controller 6,
A program for varying the irradiation output of the energy beam according to the carbon content of the camshaft 2 is preset, and a control signal C is applied from the controller 6 to each energy source 5 based on the signal S. As a result, the energy source 5 supplies each beam torch 4 with energy d for generating an energy beam with an irradiation output corresponding to the carbon content of the camshaft 2.

As shown in the figure, one torch 4 irradiates the surface of the cam 21.22 on the camshaft 2 with an energy beam, and then the other torch 4 irradiates the surface of the cam 2324 on the camshaft 2 with an energy beam. It is now possible to do so. Furthermore, when the surface of the cam 23.24 is irradiated with an energy beam by the other torch 4, the surface of the cam 21.22 of the new camshaft 2 is irradiated with an energy beam by one torch 4, and thereby , the cams 21 to 24 on the camshaft 2 can be sequentially and continuously remelted and hardened.

The measuring device 3 for measuring the carbon content of the camshaft 2 is an application of a device used for non-destructive testing of metal products. By disposing a coil and energizing the coil, a magnetic field is generated around the camshaft 2,
Detecting the magnetic permeability of the camshaft 2 within the magnetic field,
Based on this, the carbon content of the camshaft 2 can be measured.

Now, to explain the energy beam irradiation method using the beam torch 4, as shown in an enlarged view in FIG. As shown by arrows (b), by reciprocating within a predetermined range, the energy beam X irradiated from the beam torch 4 creates a trajectory X on the cam surfaces 21' to 24' of each cam 21 to 24.
' is formed so that each cam surface 21'-24' is remelted. Alternatively, the beam torch 4 may be fixed, the camshaft 2 may be rotated, and the camshaft 2 may be moved back and forth in the direction of the arrow (b) within a predetermined range.

Next, to explain the operation of this embodiment, as shown in FIG. 1.2, each cam 21 to 2 on the camshaft 2 is
The cam surfaces 21' to 24 of the camshaft 2 are remelted and hardened, and the molten state of the camshaft 2 depends on the carbon content. That is, as is clear from the phase diagram of carbon steel shown in Fig. 3, the semi-molten state containing gamma iron in the molten structure (region indicated by L + γ in the figure), or the semi-molten state containing gamma iron in the molten structure WAL, or Fe50 or graphite in the molten structure WAL The temperature at which the entire structure transitions from a semi-molten state (area indicated by −L, +Feg○ or graphite in the figure) to a molten state (area indicated by ) contained in the cast iron constituting the camshaft 2 Therefore, the state of formation of the chill layer formed by solidifying the molten structure changes depending on the carbon content. In this embodiment, each cam 21
24 cam surfaces 21 to 24' are irradiated with the energy beam X, the carbon content of the camshaft 2 is measured by the measuring device 3, and each cam surface 21 to
The irradiation output of the energy beam X is controlled so that a required hardened layer is formed on the wafer 24. As a result, even if the carbon content, which affects the melting state of the camshaft 2, is different for each camshaft 2, the cam surfaces 2,' to 24 of each camshaft 2 are uniformly chilled. Since a necessary hardened layer is generated in the chain portion, all the camshafts 2 can be finished with uniform hardness.

In this embodiment, the carbon content of the camshaft 2 is measured by the measuring device 3, and the irradiation output of the energy beam is controlled according to the carbon content, but the silicon content of the camshaft 2 is It is known that the quantity also has a considerable effect on the formation of a hardened layer. Therefore, the measuring device 3 is configured to be able to measure the carbon content and silicon content of the camshaft 2, and the As shown in FIG. 1, the carbon content and silicon content of the camshaft 2 are measured by the measurement mode switching signal e from the main controller 7, and the irradiation output of the energy beam is controlled based on this. You may do so. Moreover, as the energy beam, an electron beam, a laser beam, etc. can be considered.

(Effects of the Invention) As described above, according to the first and second inventions, at least the carbon content in the workpiece is measured before the energy beam is irradiated onto the surface of the workpiece to be hardened, and the carbon content in the workpiece is measured. Accordingly, the irradiation output of the energy beam is controlled so that the required hardened layer is formed on the surface of the workpiece to be hardened. However, the surface of each workpiece to be hardened is uniformly chilled and the required hardened layer is formed, so that all the workpieces can be finished with uniform hardness.

[Brief explanation of the drawing]

Fig. 1.2 shows an embodiment of the present invention, Fig. 1 is an overall system diagram showing a schematic configuration of a remelting hardening device according to this embodiment, and Fig. 2 shows an energy beam irradiation method using the device. It is an explanatory view showing an example. Moreover, FIG. 3 is a state diagram of carbon steel shown in connection with this example. DESCRIPTION OF SYMBOLS 1... Re-melting hardening device, 2... Work (camshaft), 21-24... Surface to be hardened (cam surface), 3...
... detection means (measuring device), 4 ... energy beam irradiation means (beam torch), 6.7 ... control means (6
... controller, 7... main controller),
X...Energy beam. Applicant: Mazda Motor Corporation - Agent: Masaaki Fukuoka -

Claims (2)

[Claims] (1) In a method of remelting and hardening the surface to be hardened by irradiating the surface of the workpiece with an energy beam,
Before irradiating the energy beam, at least the carbon content in the workpiece is measured, and the irradiation output of the energy beam is controlled according to the carbon content so that a required hardened layer is formed on the surface of the workpiece to be hardened. A remelting and hardening method characterized by: (2) In an apparatus for remelting and hardening the surface to be hardened by irradiating the surface of the workpiece with an energy beam,
an energy beam irradiation means for irradiating the energy beam; a detection means for detecting at least the carbon content in the workpiece before irradiation with the energy beam by the irradiation means; 1. A remelting and curing apparatus comprising: a control means for controlling the irradiation output of the energy beam so that a desired hardened layer is formed on the surface to be hardened.