JP2000326077A - Method of producing of corrosion resistant and wear resistant part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve corrosion resistance, wear resistance, strength and productivity by joining a Ni-B-Si-Mo-WC alloy and a steel material with diffusion under a specified joining bearing pressure and a joining temp. SOLUTION: A Ni-B-Si-Mo-WC alloy (hereafter referred to as a 203 alloy, which contains by weight, 1.0-3.0% B, 2-5% Si, 10-20% Mo, 25.0-35.0% WC and the balance Ni, and a steel material are joined with diffusion under the conditions of a joining bearing pressure of 2.5-22.5 kPa and a joining temp. of 1,060-1,110 deg.C. For example, in order to produce a check valve 5 for a plastic injection forming machine, having a base material 10 made of a cylindrical steel material (SKD61) and a corrosion-resistant and wear resistant material 11 extended from the steel material to a coaxial cylinder shape, a green compact of 203 alloy is compacted/sintered in a vacuum furnace, the corrosion and wear resistant material 11, in which a section to be a jointing face is plane ground, is stuck on the base material 10, by applying a bearing pressure and setting in a vacuum furnace, the assembly is heated and then quickly chilled to be tempered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a component requiring corrosion resistance and abrasion resistance, and more particularly to improvement of corrosion resistance and abrasion resistance, improvement of strength and improvement of productivity. And a method for manufacturing a corrosion-resistant and wear-resistant part.

[0002]

2. Description of the Related Art In general, components such as a check valve and a screw head in a plastic injection molding machine are always in contact with a resin fed under high temperature and high pressure, so that corrosion and abrasion tend to occur. In particular, in recent years, with the expansion of use of engineering plastics and the like, corrosion and wear of the above components due to flame retardants and inorganic fillers added to resins for the purpose of improving the performance of engineering plastics have become a serious problem. In addition, in order to reduce the thickness of the engineering plastic product in order to reduce its weight, the molding pressure is high and the strength of the component parts is further required.

FIG. 5 is a view showing the structure of the tip of a screw of an injection molding machine.
Screw 2 having helical ridges 2a formed on the outer periphery
Are rotatable and movable in the axial direction. A screw head 3 is fixed to the tip of the screw 2 by a screw, and a spacer 4 is interposed and fixed between the screw 2 and the screw head 3.

A small-diameter shaft portion 3a having a smaller diameter than the distal end portion is formed at an intermediate portion of the screw head 3, and a ring-shaped check valve 5 is fitted to the small-diameter shaft portion 3a. A radial gap is formed between the inner surface of the check ring 5 and the small-diameter shaft portion 3a, and moves along the small-diameter shaft portion 3a between the large-diameter portion of the screw head 3 and the spacer 4. It is possible. An axial groove 3b is formed in the large diameter portion of the screw head 3.

As described above, when the screw 2 rotates backward in the direction of arrow A and retreats in the direction of arrow B, the screw 2
The resin in the gap between the screw head 3 and the cylinder 1 is moved forward, passes through the gap between the small-diameter shaft portion 3a of the screw head 3 and the inner surface of the check valve 5 and the axial groove 3b of the screw head 3, and the tip of the screw head 3 Between the cylinder and the tip of the cylinder. In this way, when the required amount of resin corresponding to the volume of the injection-molded article is filled at the tip of the cylinder, both the rotation and the backward movement of the screw 2 are stopped.

Then, when the screw 2 is advanced next,
The resin filled at the tip of the cylinder becomes the nozzle 1a.
Extruded from. On the other hand, at this time, the check ring 5 contacts the end face of the spacer 4 and the check ring 5
The resin is prevented from leaking to the outer peripheral surface side of the screw 2.

As described above, since screw components such as screws and check valves are always in contact with high-temperature and high-pressure resin, their contact surfaces are required to have wear resistance and corrosion resistance.
When the resin is metered and accumulated, the screw retreats while rotating, but during this time, the check ring is pressed against the rear end face of the large diameter portion of the screw head, so friction occurs between the check ring and the screw head, Wear occurs on both.

[0008]

SUMMARY OF THE INVENTION From such a viewpoint,
JP-A-64-24718 discloses a high-performance screw part for an injection molding machine in which a screw head, a check valve, or a spacer is made of ceramic having excellent corrosion resistance and wear resistance. From the same viewpoint, Japanese Patent Application Laid-Open No. Sho 62-130818 discloses an injection molding machine in which abrasion resistance and strength are improved by using ceramics for parts requiring abrasion resistance. . However, these technologies use ceramics in the parts that require wear resistance, so they are excellent in wear resistance, but they are inferior in toughness due to the inherent characteristics of ceramics, and are used under high pressure. Not very suitable for

To solve such a problem, Japanese Patent Application Laid-Open No. 9-155
No. 938 discloses a backflow prevention device for an injection molding machine in which the strength of parts is increased by using high-strength stainless steel as a base material. However, not only the parts requiring abrasion resistance but also the base material need to be processed from the adjustment of the raw material powder to the molding and sintering steps, so that the productivity is reduced and the cost is increased. There is.

Therefore, it is conceivable that a commercially available steel material is used as a base material, and a high-strength material commercially available as a wear-resistant material is joined to only a portion requiring wear resistance. However, general wear-resistant materials are manufactured by powder metallurgy, and the sintering temperature of the member is 1200.
Higher than ℃. For this reason, the sinter joining in which the steel material is joined simultaneously with the sintering of the wear-resistant material is difficult because the steel material may be deteriorated.

There is also a problem that a large difference in the coefficient of thermal expansion between the wear-resistant material and the steel material may cause a crack at the joint interface. On the other hand, it is also conceivable to use a wear-resistant material by joining a wear-resistant material and a steel material by using a brazing material or other insert materials to prevent the steel material from deteriorating or cracking. Here, when the purpose is high strength bonding, it is generally known to use a Ni brazing material as an insert material because it is easily available and the bonding strength is relatively high at about 1.3 GPa. ing. However, the manufacturing cost is increased in that the insert material cost and the processing cost are required. In addition, it cannot be said that recent plastic molding machine parts are sufficiently satisfactory in terms of strength.

The present invention has been made in view of the above circumstances, and provides a method for manufacturing a corrosion-resistant and abrasion-resistant part capable of realizing an improvement in corrosion-resistant and abrasion resistance, an improvement in strength, and an improvement in productivity. The purpose is to do so.

[0013]

That is, the present invention provides:
1.0 to 3.0 wt% B, 2 to 5 wt% Si, 10
A Ni-B-Si-Mo-WC alloy (hereinafter referred to as M203 alloy) containing -20% by weight of Mo and 25.0-35.0% by weight of WC, with the balance being Ni and unavoidable impurities; And the bonding surface pressure of 2.5 to 22.5
An object of the present invention is to provide a method for producing a corrosion-resistant and abrasion-resistant component which is joined by diffusion under the conditions of kPa and a joining temperature of 1060 to 1110 ° C.

Here, it is preferable that the joining of the M203 alloy and the steel material is a joining of flat portions.
Preferably, the steel material is SKD61, and quenching is performed simultaneously with the joining. Further, it is preferable to perform a nitriding treatment after the joining.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a corrosion-resistant and abrasion-resistant part according to the present invention will be described in detail.

[0016] The production method of the present invention comprises: a corrosion-resistant and abrasion-resistant material mainly used for a portion where corrosion-resistance and abrasion resistance are required;
The steel material used for the other base material is bonded by diffusion under predetermined conditions to produce a corrosion-resistant and wear-resistant part such as a part for a plastic molding machine.

As the corrosion-resistant and abrasion-resistant material according to the present invention, M
203 alloy, which is 1.0-3.0 wt% B, 2-5 wt% Si, 10-20 wt% M
o and 25.0 to 35.0% by weight of WC, and the balance is required to be composed of Ni and inevitable impurities.

In such a corrosion and wear resistant material, Ni
Is based on a binder phase of hard particles. Further, B forms a boride with Mo and Ni, and is added in order to increase the strength and wear resistance. However, if it is less than 1.0% by weight, the amount of boride formed is small. 0
If the content exceeds% by weight, the amount of boride formed increases, and the strength tends to decrease. Si is the bonded phase N
i is added to form a solid solution in i to strengthen the alloy. If the content is less than 2% by weight, the amount of solid solution in the binder phase is small, and the strength is low. -Si compounds tend to be formed and the strength tends to decrease, which is not preferred. Mo is added in order to enhance corrosion resistance, further form borides with Ni and B, and to increase strength and wear resistance. If less than 10% by weight, there is no corrosion resistance effect, and the amount of boride formed If the content exceeds 20% by weight, the strength is lowered and the sintering temperature is increased, which is not preferable. WC is added to increase the wear resistance and strength of the alloy. However, if it is less than 25.0% by weight, the effect of wear resistance and strength is small, and if it exceeds 35.0% by weight, the binder phase is added. This is not preferred because the amount tends to decrease and the strength tends to decrease.

It is considered that, when the alloy has the composition in the above range, double borides that increase the strength and hardness of the alloy are formed and Si is solid-solution strengthened in the Ni bonding phase. Thereby, it is excellent in corrosion resistance, wear resistance and strength. In addition, under the predetermined conditions of the present invention, it is possible to join with a steel material with high strength without requiring an insert material. For details of the corrosion-resistant and abrasion-resistant material, reference can be made to JP-A-8-67937.

As the steel material according to the present invention, various steel materials can be used as long as the effects of the present invention are not impaired, but the coefficient of thermal expansion is 9 to 13 × 10, which is close to that of M203 alloy.
^-6 is preferably used. Above all, SKD61
It is particularly preferred to use (see JIS G 4404). This is because, among the commercially available steel materials, i) excellent hardenability and high toughness value, and ii) quenching can be performed at the joining temperature with the corrosion and wear resistant material, so that the corrosion and wear resistant material is This is because deterioration can be prevented, and iii) since the thermal expansion coefficient of the material is close to that of the corrosion-resistant and abrasion-resistant material, cracking of the bonding interface can be prevented.

Here, in the method of the present invention, in order to join such a corrosion-resistant and abrasion-resistant material and a steel material by diffusion, a surface pressure is applied to a joining surface of the two materials to enhance the adhesion between the two materials. The bonding surface pressure at this time is 2.5 kPa to 22.
5 kPa, preferably 10 kPa to 2 kPa.
0 kPa. If the bonding surface pressure is too high, the adhesion of the bonding surface is improved, but the corrosion-resistant and abrasion-resistant material is undesirably deformed during the heat treatment. On the other hand, if the joining surface pressure is too low,
Voids remain at the bonding interface, and the adhesion is undesirably reduced.

Further, a plane portion is formed on each of the materials to be joined in advance, and the plane portions are joined to each other so that the joining portions are joined with uniform pressure without unevenness. This is preferable because higher adhesion can be ensured. Note that the shape of the joining portion may be a curved surface as long as the joining can be performed while ensuring sufficient adhesion.

The bonding temperature at this time is 1060 ° C.
It is required to be 1110 ° C., preferably 1070 ° C.
１1100 ° C. If the joining temperature is too high, the steel material serving as the base material is deteriorated, and the strength of the M203 alloy is also reduced. On the other hand, if the joining temperature is too low, the bending strength becomes insufficient, which is not preferable.

Further, in the manufacturing method of the present invention, it is preferable to perform a nitriding treatment after joining the two materials. Such a nitriding treatment is not particularly limited, and can be performed according to a known method. As a result, the surface hardness of the base material can be further increased, and the formation of compounds on the surface of the corrosion-resistant and abrasion-resistant material can be prevented. Further, the deformation amount of the base material (steel material) and the corrosion and wear resistant material can be extremely reduced.

Hereinafter, the present invention will be described more specifically based on a check valve for a plastic injection molding machine, which is an example to which the present invention is applied, but the present invention is not limited to this. Instead, it can be applied to various parts requiring corrosion resistance and abrasion resistance, such as screw heads and spacers for plastic injection molding machines.

FIG. 1 shows an example of a check valve 5 for a plastic injection molding machine manufactured according to the present invention. FIG. 3A is a longitudinal sectional side view of the check ring 5, and FIG.
FIG. 5 is an arrow view in a cross section taken along line bb of FIG.

The check valve 5 is for preventing the resin from flowing back in the plastic injection molding machine. The check valve 5 has a base material 10 made of a cylindrical steel material and a cylindrical shape having the same axis from one end of the steel material. Corrosion and wear resistant material 1 extending
And 1. As described in detail with reference to FIG. 5, the check valve 5 is located between the screw head 3 located at the tip of the screw 2 and the screw 2 and is movably arranged in the screw axial direction. When the resin is metered, the screw head 3 is pushed forward and comes into contact with the rotating screw head 3, so that the contact surface between the screw head 3 and the check valve 5 is required to have wear resistance. Further, the check ring 5 receives a high resin pressure during injection, and is required to have high strength and high toughness. From such a viewpoint, as shown in FIG. 1, the parts of the check valve 5 where the wear resistance is required include:
The above-mentioned M203 alloy is used as the corrosion and wear resistant material 11.

An example of a method for manufacturing such a check valve 5 will be described below. Here, M203 alloy, that is, Ni- (1.0 to 3.0)% B- (2 to 5)% S is used as a corrosion-resistant and wear-resistant material to be used in a part requiring wear resistance.
i- (10-20)% Mo- (25.0-35.0)%
A WC alloy was used. Table 1 shows the characteristics of the corrosion-resistant and abrasion-resistant material.

[0029]

[Table 1]

First, the raw material powder (specifically, Ni-2.2% B-3.2% Si-30% WC) is made to have the above composition.
-15% Mo) and mixed and pulverized by a rotary ball mill. Then, it dried and produced the alloy powder.

Next, the above alloy powder was molded by a uniaxial pressure molding method (press molding method) using a mold. The dimensions of the mold were determined in consideration of shrinkage generated during sintering of the compact and grinding allowance during finishing.

First, as shown in FIG. 2, a mold 12 is filled with the corrosion-resistant and abrasion-resistant material powder 11a, and a pressing punch 13 is inserted into an upper portion of the mold. Then, the compact 11 a was taken out of the mold 12. The formed body 11a was set in a vacuum furnace, and sintered at a sintering temperature of 1070 ° C. and a pressure of 4 to 7 Pa to obtain a corrosion-resistant and abrasion-resistant material 11. After sintering, the surface to be joined was subjected to surface grinding. On the other hand, as the substrate 10, S
Using KD61, it was processed into a cylindrical check valve.

The joining and quenching were performed in a vacuum furnace. As shown in FIG. 3, the corrosion-resistant and abrasion-resistant material 11 and the substrate 10 were overlapped, a 2.2 kg weight 15 was placed thereon, a surface pressure (17.4 kPa) was applied to the joint surface, and the furnace was set in a furnace. At this time, BN (boron nitride) was applied to the surface where the weight 15 and the corrosion-resistant and abrasion-resistant material 11 were in contact with each other for the purpose of mold release. After being kept at 1090 ° C. for 30 minutes, it is rapidly cooled to room temperature, and 600 ° C.
Tempering treatment was performed twice for 180 minutes. After the treatment, the hardness of each part is HRA85 for the hard layer and HR for the base material.
C48. As shown in FIG. 1, the outer diameter, the inner diameter, and both end faces are set to predetermined dimensions (outer diameter 60 mm, length 40 m).
m) was ground and ion-nitrided to perform a nitriding treatment to produce a check valve. The surface hardness of the substrate after the nitriding treatment was HV1050.

When the check valve thus manufactured was incorporated into a plastic injection molding machine and operated, it was found to be about 5 times as large as that of a conventional check valve made of SKD61 (only quenching treatment). Life has expired. The amount of wear on the outer peripheral surface in contact with the barrel was also reduced. Also, no damage such as cracks occurred from the joint.

[0035]

EXAMPLES (Examples 1 to 5) The bending strength of each test piece obtained by bonding at various bonding temperatures was measured.
FIG. 4 shows the shape of the test piece 16. 35 × 20 × 8mm
M203 alloy (Ni- (1.0-3.0)% B- (2
-5)% Si- (10-20)% Mo- (25.0-3
5.0)% WC alloy) and SK having the same shape
D61 was measured under the conditions shown in Table 2 (joining surface pressure 12 kP
Under a), bonding is performed on a 35 × 8 mm surface, and 8 × 4 × 26
mm bending test pieces were prepared. With respect to the obtained test piece, the bending strength was measured by a three-point bending bending test in accordance with JIS B4053. Table 2 shows the flexural strength obtained under each bonding condition.

(Comparative Examples 1 to 5) A bending test piece was prepared in the same manner as in the example except that the insert materials shown in Table 2 were used for joining, and the bending strength was measured. Table 2 shows the bending strength of each test piece obtained by bonding at each bonding temperature.

[0037]

[Table 2]

From the results, the following can be understood. i)
If the joining temperature is too high, the steel material serving as the base material is deteriorated.
ii) When insert material BAg-8A is used, bonding at a low temperature is possible, but the bending temperature is as low as 0.7 GPa. iii) When the insert material BNi-2 is used, at a joining temperature of 1070 to 1090 ° C., a bending strength of 1.7 GPa
Is obtained. iv) When the insert material was not used, the bending strength was 0.5 GPa or less at a joining temperature of 1050 ° C. or less (not shown in the table). 5) When the insert material is not used, at a joining temperature of 1060 to 1110 ° C,
Bending strength higher than that using the insert material BNi-2 was obtained. 6) Without using insert material,
The M203 alloy and the steel material were joined, but no defects such as cracks due to the difference in the coefficient of thermal expansion occurred. Therefore, the effect of the present invention is clear. When the insert material was not used, the bending strength was 1.6 GPa at a joining temperature of 1120 ° C. or higher.

[0039]

As described above, according to the method for manufacturing a corrosion-resistant and abrasion-resistant part according to the present invention, since joining can be performed without the need for an insert material, low cost and high productivity can be achieved.
Corrosion and wear resistant parts can be manufactured. In addition, it is possible to manufacture a corrosion-resistant and abrasion-resistant part having no defect and having extremely excellent corrosion-resistance and abrasion resistance and strength.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional side view of a check valve manufactured according to the present invention, and FIG. 1B is a sectional view taken along line bb of FIG. 1A.

FIG. 2 is a view showing a mold forming of a corrosion-resistant and abrasion-resistant material in the present invention.

FIG. 3 is a diagram showing a state when the corrosion-resistant and abrasion-resistant material and the base material are joined in the present invention.

FIG. 4A is a side view of a bending test piece, and FIG. 4B is a cross-sectional view of FIG.

FIG. 5 is a sectional view showing a screw head of a general plastic injection molding machine.

[Explanation of symbols]

 2 Screw 3 Screw Head 3a Small Diameter Shaft 5 Check Valve 10 Base 11 Corrosion-Resistant and Wear-Resistant Material 11a Corrosion-Resistant and Abrasion-Resistant Material Powder 12 Mold (Die) 13 Punch 14 Core Rod 15 Weight 16 Test Piece

Claims (4)

[Claims] (1) 1.0 to 3.0% by weight of B, 2 to 5% by weight
Si, 10-20 wt% Mo and 25.0-3
A Ni-B-Si-Mo-WC alloy containing 5.0% by weight of WC, the balance being Ni and unavoidable impurities, and a steel material were bonded at a bonding surface pressure of 2.5 to 22.5 kPa and a bonding temperature. Under the conditions of 1060 to 1110 ° C,
A method for producing a corrosion-resistant and abrasion-resistant part, characterized by joining by diffusion. 2. The bonding between the Ni-B-Si-Mo-WC alloy and the steel material is to join flat portions together.
A method for manufacturing a corrosion-resistant and wear-resistant part according to claim 1. 3. The method according to claim 1, wherein the steel material is SKD61, and quenching is performed simultaneously with the joining. 4. A nitriding treatment is performed after the joining.
The method for producing a corrosion-resistant and abrasion-resistant part according to any one of claims 3 to 4.