JPH03177582A - Production of member having amorphous layer - Google Patents

Abstract

PURPOSE:To prevent a crack from being caused in a surface build up welding layer by forming nonmagnetic alloy as a first build up welding layer and forming alloy which is made amorphous by rapid cooling coagulation thereon as a second build up welding layer and impressing high-intensity energy on this layer to perform rapid redissolution and rapid coagulation and forming an amorphous pattern. CONSTITUTION:Nonmagnetic alloy free from martensitic transformation is formed as a first build up welding layer 5 on an iron-based alloy base body 1 which causes martensitic transformation. An alloy layer 6 is formed between both. Alloy which is made amorphous by rapid cooling coagulation is formed as a second build up layer 10 thereon. An alloy layer 11 is formed between both. High-intensity energy (laser) 13 is impressed on the second build up layer 10 to perform rapid dissolution and rapid recoagulation and an amorphous pattern 14 is formed. Thereby the strength difference of an output signal is made large in detection of the magnetic characteristics in the amorphous part or the crystalline part on the surface build up welding layers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a member having an amorphous layer pattern on its surface, which is used for a non-contact type sensor for detecting position or velocity.

[Conventional technology]

Torque sensors are known that measure the torque of the rotating shaft by fixing an amorphous magnetic alloy thin film with induced magnetic anisotropy and a large inverse magnetostrictive effect to the rotating shaft of a metal base (for example,
Japanese Patent Publication No. 63-20031, "Nikkei New Materials 4, February 16, 1987 issue, pages 10 to 11). Also, as a method for obtaining a member having an amorphous alloy layer on the surface of a Cu or Ni metal substrate. , “Nikkei Mechanical J
In the January 26, 1987 issue, pages 28 to 29, an alloy thin film that easily becomes amorphous is bonded to the substrate surface by the HIP method (800°C), and then a pulsed laser is irradiated onto the alloy thin film surface to rapidly bond it. A method is disclosed in which the surface layer of the alloy thin film is made amorphous by melting and rapidly solidifying it.

The inventors of the present invention have also published Japanese Patent Application No. 63-297344 (
(filing date: November 25, 1988), an overlay weld layer of an alloy that easily becomes amorphous is formed in a crystalline state on a metal substrate, and high-density energy such as a laser is applied to this overlay weld layer. A method to form an amorphous surface layer was proposed. As described in the claims, the manufacturing method in this proposed patent application is to "place an alloy that becomes amorphous by rapid solidification on a base material, and use high-density energy to transform the alloy into a matrix. After overlay welding, the surface of the overlay is finished by mechanical processing, and then high-density energy is applied to the surface of the overlay to rapidly melt and rapidly resolidify the surface of the overlay. A method for manufacturing a member having an amorphous layer, which method comprises making the layer amorphous. This manufacturing method is as follows: (1)
I material (345C) An alloy powder that is easily amorphous is placed on a base, melted by laser (high-density energy) irradiation, and overlay welded to the steel base, (2) forming a crystalline overlay weld layer. (3) scan and irradiate the overlay welding layer with a laser (high density energy) to rapidly remelt and resolidify the irradiated area to form an amorphous surface layer. In other words, it forms. This amorphous surface layer is formed into a predetermined pattern to make the overlay welding layer into a pattern consisting of an amorphous part and a crystalline part, and this change pattern of magnetic properties is detected by a detector (magnetic) having an excitation coil and a detection coil. position, speed, etc. can be detected by reading it with a sensor).

[Problem that the invention attempts to solve]

However, the proposed manufacturing method has the following problems. In other words, when overlaying an alloy that easily becomes amorphous, if the base material is a metal such as carbon steel that undergoes martensitic transformation and volumetric expansion during quenching, the heat-affected area due to overlaying welding will expand in volume. This causes tensile internal stress to occur in the overlay weld layer, which may cause cracks to occur in the overlay layer. In addition, materials that undergo martensitic transformation when heated and cooled, such as carbon steel, are ferromagnetic, and the magnetic properties of the amorphous and crystalline parts in the overlay weld layer formed on this base material When detecting a change pattern, the difference in detection signal strength becomes small due to the influence of the ferromagnetic substrate.

The present invention is an improvement of the manufacturing method previously proposed by the inventors, and includes an amorphous layer that prevents cracks from occurring in the overlay weld layer and prevents the difference in detection signal intensity from becoming small. An object of the present invention is to provide a method for manufacturing a member having the following.

[Means to solve the problem]

The above-mentioned purpose is to form a non-magnetic alloy that does not undergo martensitic transformation as a first overlay welding layer on an iron-based alloy substrate that causes martensitic transformation, and then to form an amorphous alloy by rapid solidification on top of the first overlay welding layer. is formed as a second overlay welding layer,
Achieved by a method for manufacturing a member having an amorphous layer, characterized in that high-density energy is applied to the second overlay welding layer to cause rapid remelting and rapid resolidification to form an amorphous layer pattern. Ru.

[For production]

What is an alloy that does not undergo martensitic transformation and is non-magnetic?
For example, there are austenitic stainless steels, copper alloys, aluminum alloys, magnesium alloys, titanium alloys, etc.
It is preferable to melt this using high-density energy such as a laser, TIG arc, brass arc, or electron beam and overlay weld it onto the base. Note that in this case, plasma spraying is also included. This alloy is prepared as a powder or a wire, and an appropriate one is used depending on the overlay welding method.

The addition of this first build-up weld layer of non-magnetic alloy is the main difference from the previously proposed manufacturing method, and the presence of this build-up weld layer allows the formation of an alloy that easily becomes amorphous on top of it. Even if an iron-based alloy substrate such as carbon steel undergoes martensitic transformation and expansion during overlay welding, the first overlay weld layer will not undergo transformation expansion and will allow the base to expand without causing any cracks in its white. Because of the relaxation, cracks do not occur in the second overlay weld layer of the alloy that is easily made amorphous. Furthermore, since the first overlay weld layer is non-magnetic, it does not affect the detection signal when a magnetic field is applied to detect the pattern of change in magnetic properties between the amorphous part and the crystalline part. This prevents the influence of the base material, which is a ferromagnetic alloy.

Therefore, the difference in detection signal strength based on the difference in magnetic properties becomes clear (larger than before).

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail by way of embodiments with reference to the accompanying drawings.

1A to 1G are schematic cross-sectional views of a member having an amorphous layer for explaining the manufacturing process according to the manufacturing method according to the present invention, and FIG. 2 is a longitudinal cross-sectional view of the manufactured member. It is a drawing showing the relationship with a detection sensor.

A component with an amorphous layer is manufactured according to the invention as follows.

As shown in FIG. 1A, an iron-based alloy substrate 1 that undergoes martensitic transformation and is ferromagnetic, such as carbon steel, is prepared, and an alloy material that does not undergo martensitic transformation and is non-magnetic, such as austenitic stainless steel, is placed thereon. (Powder) 2 is placed. As other materials, alloy powders such as copper alloy, aluminum alloy, magnesium alloy, titanium alloy, etc. may be used.

Next, by irradiating and scanning a laser 3 with high-density energy, the arranged powder is sequentially and continuously melted to form a molten metal boule 4, and the molten metal boule 4 is cooled and solidified to form a first overlay weld layer 5. do. At this time, an alloy layer 6 is formed at the interface between the base body 1 and the overlay weld layer 4.

In the case of FIGS. 1A and 1B, an alloy powder overlay material and a laser are used, but the first overlay weld layer is formed using a wire-like alloy overlay material using a known TIG arc welding method. 5 can be formed. Furthermore, the first build-up layer can also be formed by a known plasma spraying method.

The first overlay weld layer is a metal material that does not undergo martensitic transformation, and even if the heat-affected zone of the base undergoes martensitic transformation and expands, the internal stress of the first overlay weld layer due to its deformation is within the allowable range and cracking will occur. do not.

As shown in FIG. 1C, the surface of the first overlay weld layer 5 is machined (cutting or grinding) to make it smooth and have a predetermined thickness. Note that this machining can be omitted if it is not necessary.

Next, as shown in FIG. 1D, an alloy that easily becomes amorphous is placed on the first overlay welding layer 5 as an overlay material (powder) 7. Examples of alloys that can be easily made amorphous include Fe-B
system, Fe-P system, Fe-P-C system, Pd-3i system, Fe
There are alloys such as -3i-B series and Co-3i-B series, but the important thing is to select the optimum one according to the use of the member, and the alloy composition is not particularly limited.

After that, as shown in FIG. 1E, the laser 8 is irradiated,
The powder placed by scanning is sequentially and continuously melted to form a molten metal pool 9, which is cooled and solidified to form a second overlay welding layer 10. At this time, an alloy layer 1 is formed at the interface between the first overlay weld layer 5 and the second overlay weld layer 10.

Unlike the case of FIGS. 1D and 1E described above, the second overlay weld layer 10 can be formed using a wire-like overlay material instead of powder using the known TIG arc welding method. . Furthermore, the first build-up layer can also be formed by a known plasma spraying method.

In either case, the cooling after melting of the overlay material is mainly due to self-cooling due to heat conduction to the base l through the first overlay welding layer 5, and the overlay material solidifies relatively quickly, but the second overlay welding Because the overall thickness of the layer is relatively thick, it is not ultra-quenched, resulting in a crystalline layer with a fine structure.

After that, as shown in FIG. 1F, the second overlay weld layer IO
is machined to a predetermined thickness (for example, 0.01 mm or more). Since the thickness of the second overlay weld layer is thin, grinding is desirable.

Next, as shown in FIGS. 1G and 2, high-density energy (laser, electron beam, T-G arc, plasma arc, etc.) 13 is applied to the second overlay weld layer lO in a crystalline state to cause rapid regeneration. The amorphous layer 14 is formed by melting and rapid resolidification by self-cooling. Here, it is necessary to appropriately set conditions for applying high-density energy (eg, laser output, laser scanning speed, laser irradiation beam diameter, etc.) so as to make the crystal layer amorphous. The amorphous layer 14 has a predetermined gap D in a linear shape (stripe shape) extending in a direction perpendicular to the longitudinal direction of the product.
(Fig. 2). In this way, the pattern is such that amorphous partial stripes 14 and crystalline partial stripes appear alternately in the longitudinal direction of the product. Even with this heating and cooling during rapid remelting and resolidification, the first build-up layer 5 does not undergo martensitic transformation, so the cracks caused by transformation expansion that conventionally occur do not occur in the second build-up layer IO. Finally, the second
The surface of the overlay weld layer 10 is finished by grinding or polishing before use.

A member 15 having an amorphous layer manufactured in this way (
In FIG. 2), the second build-up layer 10 has an alternating pattern surface of amorphous portions 14 and crystalline portions, and as shown in FIG. It is possible to detect the difference in detection signal strength due to the difference in magnetic properties between the magnetic field and the magnetic field. This can be used to measure position and velocity. The magnetic sensor 6 consists of an excitation coil and a detection coil, and a high-frequency excitation current is supplied to the excitation coil from an oscillation/amplification circuit 17, and the detection signal obtained from the detection coil is divided into an amorphous portion and a crystalline portion. The output potential corresponds to the magnetic properties of the

Example As shown in FIG. 1A, Si4.6wt%-B2.2wt% was used as a material for overlaying 2 that is easily amorphous, as shown in FIG.
- Alloy powder with the remainder being Fe in a width of 10 mm and a thickness of 2 m.
Placed in a straight line with □. The powder is irradiated with a CO□ laser 3 as shown in FIG. 1B, and the laser is scanned in the longitudinal direction while oscillating at right angles to the longitudinal direction of the disposed powder 2, thereby depositing the powder onto the base 1. The first overlay layer 5 was formed by welding. The laser irradiation conditions at this time are as follows.

Laser beam: A beam condensed to a size of φ2 mrn by a condenser lens is oscillated with an amplitude width of 8III1.

Oscillation rate: 180Hz Laser output 2.5 kills Laser scanning speed: 200mm/m1n (moving speed of the base 1) Next, as shown in FIG. 1C, the surface of the first overlay layer 5 is ground to Processing was performed so that the thickness of the layer 5 was 1.0 mm.

As shown in FIG. 1D, the alloy powder 7, which becomes amorphous through ultra-rapid solidification, is spread over the first build-up layer 5 to a width of 510 [11° and a thickness of 2.
They were arranged in a straight line at u. The composition of this alloy powder is Si4.
9%-B4゜0%-balance Fe (A alloy) or Si4.7
%-B3.8%-balance Co (B alloy). The powder 7 is irradiated with a C02 laser 8 as shown in FIG. 1E,
The powder 7 was oscillated perpendicularly to the longitudinal direction of the powder 7 and scanned in the longitudinal direction to weld the alloy to form a crystalline second build-up layer 10. The laser irradiation conditions at this time are as follows.

Laser beam: A beam focused to a diameter of 2 mm by a condenser lens is oscillated with an amplitude width of 4 mm.

Oscillation number = 180 laser output 2.5kW Laser scanning speed: 100mm/min or 200m
m/m1n (moving speed of the substrate) After the formation of the second build-up layer 10, it was investigated whether or not cracks had occurred on the surface of the second build-up layer by penetrant testing, and the results are shown in Table 1. show. No cracking occurred in any case.

As a comparative example, the first build-up layer 5 was omitted and the second build-up layer was formed directly on the steel base 1 under the same conditions as described above, and no cracks were generated on the surface. The presence or absence of the cracks was investigated using penetrant testing, and the results are shown in Table 1. Cracks occurred in both cases.

Table 1 Presence of cracks on the surface of the build-up layer Next, as shown in Fig. 1F, the second build-up layer 10 was ground to a thickness of 0.2 mm.

Finally, as shown in Fig. 1G, YA is applied to the second overlay layer IO.
The amorphous layer 14 was formed by irradiating the G laser 13 in a stripe (line) shape perpendicular to the longitudinal direction to cause rapid remelting and rapid resolidification. This laser irradiation is performed at a predetermined gap D (0,3
mm) to form a pattern in which stripes of the amorphous layer 14 are repeated as shown in FIG. No cracks were observed in the second overlay layer including the amorphous layer 14. The laser irradiation conditions at this time are as follows.

Laser beam: Condensed into a size of φ0.2 + nm using a condensing lens.

Pulse energy: 48 mJ Pulse width: 0.5 msec Pulse repetition frequency: 50 Hz The member 15 having an amorphous layer manufactured in this manner has a structure in which the formed amorphous portion (layer 14) and the crystalline portion (the portion where the second build-up layer 10 remains) are arranged in alternating stripes, and the magnetic sensor 16
By sliding the amorphous layer 14 on the member 15 (or moving the member 15), the amorphous layer 14 can be detected, and the relative position or relative velocity can be calculated by counting the number of amorphous layers 14.

An excitation current of 2 MHz is supplied from the oscillation/amplification circuit 17 to the excitation coil of the magnetic sensor 16, and an output signal (potential) corresponding to the magnetic characteristics of the amorphous or crystalline material is obtained from the detection coil of the sensor. Since the obtained output signal reflects the magnetic properties of the material, the larger the difference in output signal intensity, the better for measurement.The difference in output signal intensity of the member 15 according to the present invention is shown in FIG. In contrast, in the conventional case, the voltage was 1.8 V, and the present invention is clearly superior. Note that this conventional case is a member in which the second build-up layer is omitted and the second build-up layer is directly formed on the base.

〔Effect of the invention〕

As described above, according to the present invention, when overlaying an alloy that is easily amorphous on an iron-based alloy substrate such as carbon steel that undergoes martensitic transformation expansion, martensitic transformation expansion can be performed according to the present invention. By forming a non-magnetic (intermediate) overlay weld layer between the base and the (surface) overlay weld layer of an alloy that easily becomes amorphous, cracks in the surface weld overlay are prevented. Moreover, it is possible to increase the difference in output signal intensity in detecting the magnetic characteristics of an amorphous portion or a crystalline portion formed in the surface welding layer. In the embodiment, a plate-like member was used, but the present invention can also be applied to a cylindrical (round bar) member, and can be used to measure the rotation angle and rotation speed.

[Brief explanation of drawings]

1A to 1G are schematic cross-sectional views taken in a direction perpendicular to the longitudinal direction of a member having an amorphous layer, illustrating the manufacturing process in the manufacturing method according to the present invention, and FIG. FIG. 3 is a diagram showing the relationship between a member (longitudinal cross section) manufactured by the manufacturing method of the invention and a detection sensor; FIG. It is a graph. 1... Base body, 5... First overlay welding layer,
3.8.13...Laser, ■0...Second overlay welding layer, 14...Amorphous layer, 16...Detection sensor. Figure 1A Figure 1B Figure 1C Figure 1D Figure 1E Figure 1F Side

Claims (1)

[Claims] 1. A non-magnetic alloy that does not undergo martensitic transformation is formed as a first overlay welding layer on an iron-based alloy substrate that undergoes martensitic transformation, and a second overlay welding layer is made of an alloy that becomes amorphous by rapid solidification. A member having an amorphous layer, which is formed as a weld layer, and is formed by applying high-density energy to the second overlay weld layer to cause rapid remelting and rapid resolidification to form an amorphous layer pattern. manufacturing method.