JPH04185414A - Composite cylinder with lining layer composed of corrosion-resistant and wear-resistant sintered alloy - Google Patents

Abstract

PURPOSE:To upgrade resistance to wear and resistance to corrosion without the possibility of infiltrating of Fe into a lining layer by making the composition of an alloy material forming the lining layer optimum and pressure sintering its alloy material on the inner face of a cylindrical material by means of the HIP process. CONSTITUTION:A lining layer is composed of 5.0-20.0wt.% of Cr, 2.5-4.0wt.% of B, 2.5-10.0wt.% of Si, 5.0-40.0wt.% of Co, 5.0wt.% or less of Fe and atomized powder of alloy composed of Ni and unavoidable impurities for the remaining portion substantially to be pressure sintered on an inner face of a cylinder matrix by means of the HIP process. In order to enhance the uniformity of composition, the grain diameter of atomized powder should preferably be in the range of approximately 5-100mum. Further, resistance to wear can be further upgraded by dispersing uniformly fine particles composed of a carbide element which belongs to the IVa family, Va family or VIa family of the periodic table in the alloy powder. In that case, it is preferable that the content is 5-60 pts.wt. per 100 pts.wt. of an Ni alloy material forming the lining layer and its grain diameter is preferably in the range of 5-100mum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composite cylinder used in a plastic molding machine, etc., and more particularly to a composite cylinder with excellent wear resistance and corrosion resistance.

[Prior art and problems to be solved by the invention] Cylinders for molding machines used for injection molding or extrusion molding of plastics, etc. are prone to corrosion or wear caused by the resin or additives added to the resin during hot molding. In order to prevent
A structure is used in which the inner surface of a hollow cylindrical base cylinder made of steel is lined with an alloy material having wear resistance and corrosion resistance by centrifugal casting.

However, when a composite cylinder for a molding machine as described above is manufactured by centrifugal casting, Fe from the steel material forming the cylinder base material invades the alloy material forming the lining layer during the welding reaction. This penetration of Fe is necessary to achieve welding between the lining layer and the cylinder base material, but
There is a problem that Fe reduces the hardness of the lining layer and also deteriorates the corrosion resistance.

In addition, in recent years, the uses of plastics have become more diverse, and various special resins and additives have come to be used. , the demand for further improvement is increasing.

For this purpose, is it necessary to mix large amounts of alloy components or add large amounts of wear-resistant components? Centrifugal casting methods do not necessarily satisfy these requirements due to problems such as segregation and dispersibility. I can't do anything.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a composite cylinder which is coated with a lining layer without Fe penetrating from the cylinder base material and whose composition can be made to have excellent wear and corrosion resistance. That's true.

[Means to solve the problem]

As a result of intensive research in view of the above problems, the present inventors optimized the composition of the alloy material forming the lining layer, and
They discovered that by pressure-sintering the alloy material on the inner surface of the cylinder base material using the HIP process, Fe would not enter the lining layer and the lining layer would have excellent wear and corrosion resistance. I came up with an invention.

That is, in the composite cylinder of the present invention comprising a lining layer and a cylinder base material layer, the lining layer is made of Cr 5
．． 0-20.0% by weight, 82.5-4.0% by weight, Si
An atomized powder of an alloy consisting of 2.5 to 10.0 wt%, Co 5.0 to 40.0 wt%, Fe 5.0 wt% or less, and the remainder substantially Ni and unavoidable impurities is HI
It is characterized in that it is formed by pressure sintering on the inner surface of the cylinder base material using the P process.

[Examples and effects]

First, the alloy components constituting the lining layer having wear resistance and corrosion resistance used in this example will be explained.

The content of Cr is 5.0 to 20.0% by weight.

Cr forms a boride with B in the matrix and is dispersed in the alloy, improving corrosion resistance and wear resistance.

However, if Cr is less than 5.0% by weight, the effect is not sufficient, and if it exceeds 20.0% by weight, the toughness of the alloy will be reduced.

The content of B is 2.5 to 4.0% by weight.

B has the effect of precipitating high hardness borides in the structure and improving the hardness of the alloy. However, if it is less than 2.5% by weight, the effect is not sufficient, and if it exceeds 4.0% by weight, the hypereutectic structure becomes coarse and brittle.

The content of Si is 2.5 to 10% by weight.

Si forms a metal compound with N1 and has the effect of improving wear resistance. However, if the Si content is less than 2.5% by weight, the effect will not be sufficient, and if it exceeds 1000% by weight, the toughness of the alloy will be reduced.

The Co content is 5.0 to 40.0% by weight.

Co combines with Cr and B to improve the hardness and corrosion resistance of the alloy. However, Co is 5.
If it is less than 0% by weight, the effect will not be sufficient, and 4
If it exceeds 0.0% by weight, its effect will be saturated and the economic effect will be lost.

The content of Fe is 5.0% by weight or less.

Ideally, it is preferable that Fe is not included. When the amount of Fe contained increases to 5% by weight or more, the hardness decreases and the corrosion resistance against acids decreases.

Further, in this example, the raw materials having the above-mentioned composition are melted and powdered by a gas atomization method. The melting point of the raw materials mentioned above is not very high, and the viscosity of the molten metal is low, so they are suitable for powdering by gas atomization. The gas atomization method can be performed by a normal method using Ar gas or the like. The particle size of the atomized powder is not particularly limited as long as HIP is possible, but it is preferably about 5 to 100 uXl in order to improve the uniformity of the composition.

Furthermore, in this example, by uniformly dispersing fine particles made of carbides of elements belonging to Group IVa, Group Va, or Group VIa of the periodic table in the above-mentioned alloy powder,
Abrasion resistance can be further improved.

When containing fine particles made of the above carbide, the content rate is:
The amount is preferably 5 to 60 parts by weight per 100 parts by weight of the N1-based alloy material forming the lining layer.

If it is less than 5 parts by weight, there will be little improvement in wear resistance;
If the amount exceeds 1 part by weight, the mechanical strength will decrease significantly, which is not preferable.

Further, in this case, the particle size of the fine particles made of carbide is 5.
~100 ETI is preferred. If it is less than 5 μm, it will not be uniformly dispersed, and if it exceeds 100 μm, the strength of the lining layer will decrease, which is not preferable.

Next, an example of a manufacturing method for the composite cylinder of the present invention will be explained.

FIG. 1 is a schematic sectional view showing a state in which a core metal for forming a lining layer is inserted into a cylinder base material, and shows the state before alloy powder is filled.

As shown in FIG. 1, by growing the hopper opening 41 and inserting the core metal 2 for forming the cylinder part of the composite cylinder inside the cylinder base material 1 made of high-strength steel, etc. An annular hollow part 3 is formed between a cylinder base material 1 and a core metal 2. Both ends of the core metal 2 and both ends of the cylinder base material 1 are sealed by joining a lid 4.5 by welding or the like.

In this case, the alloy powder for lining may be introduced through the opening 41, or, depending on the case, one of the lids 4.5 may be sealed after being filled with the alloy powder. It is preferable that the filling of the alloy powder is carried out by appropriately applying vibration to the cylinder base material. Finally, the hopper opening 41,
It is sealed with a lid 8.

Note that the core metal 2 and the lid 4.5 can be made of mild steel or the like. Further, the core metal 2 does not need to be hollow as shown in the figure, and may be solid.

FIG. 2 is a schematic sectional view showing a cylinder filled with alloy powder 3a in this manner.

The cylinder filled with the alloy powder is loaded into a HIP device 7 having a structure as shown in FIG.
The temperature is 1,050° C., the pressure is 1.000 to 1.500 a, tm, and the process is carried out for 1 to 5 hours in an inert gas atmosphere such as argon. Note that the white arrow in FIG. 3 schematically indicates the direction of pressure applied to the joined body 6.

After performing the HIP process, the lids 4 and 5 of the joined body 6 are removed by cutting or the like. Next, the core metal 2 is removed and the inner surface of the cylinder is finished.

The composite cylinder manufactured as described above has a structure in which the lining layer is formed by the HIP process, so that Fe does not invade from the cylinder base material and has excellent hardness and corrosion resistance. Moreover, since the lining layer is formed of the above-mentioned corrosion-resistant and wear-resistant alloy material, it has a structure that has even better wear resistance and corrosion resistance.

Note that by subjecting the composite cylinder of this example described above to appropriate heat treatment to give the cylinder base material a desired structure,
It is also possible to improve the strength of the cylinder base material and improve the crack resistance of the lining layer.

The cylinder base material that is most suitable for performing such heat treatment will be explained.

It is preferable to use hypoeutectoid or eutectoid alloy steel as the cylinder base material. .

When using Cr-Mo steel as the alloy steel, the content of chemical components is C0.3 to 0.5% by weight and Si 0.15 to 0.5% by weight.
35% by weight, Mn 0.3-1.5% by weight, P 0.0
3% by weight or less, S 0.03% by weight or less, Cr 0.7
From the viewpoint of strength, it is preferable that Mo content be 1.5% by weight and Mo 0.1% to 0.5% by weight. Japanese Industrial Standards (JIS G 4105
) Cr equivalent to SCM440 and SCM445 specified in
-Mo steel is particularly preferred in terms of strength.

When using Ni-Cr-Mo steel as alloy steel,
The content of chemical components is C0.3-0.5% by weight, Sin,
15-0.35% by weight, Mn 0.3-1.5% by weight
, P 0.03% by weight or less, 30.03% by weight or less, N
i 3.0% by weight or less, C 0.7 to 1.5% by weight, M
o0.1 to 0.5% by weight is preferable from the viewpoint of strength. SN specified in Japanese Industrial Standards (JIS G 4103)
Ni-Cr-Mo steel equivalent to CM439 is particularly preferred in terms of strength.

In addition, in this example, by applying appropriate heat treatment to the cylinder base material as described above, the structure is made to have an advantageous structure in terms of strength. In this case, 20% or more of the structure is formed of bainite, and the remainder is preferably formed from sorbite. If the bainite content in the structure is less than 20%, sufficient strength cannot be obtained, which is not preferable.

In order to obtain the structure shown above, in this embodiment, the above-mentioned composite cylinder is subjected to heat treatment.The heat treatment method will be explained below using the heat treatment pattern shown in FIG.

Here, the horizontal axis in Fig. 4 shows time, and the vertical axis shows temperature, and on the heat treatment pattern, A is the quenching heating process, B is the cooling process, C is the holding process, D is the heating process, and E is the heating process. In the annealing step, F indicates a cooling step to room temperature.

In this example, a composite cylinder is formed by the quenching heating step shown in A, and in the cooling step shown later, it is cooled to a temperature range where bainite transformation occurs, but the cooling rate at this time is 40-100" If the cooling rate is less than 40°C/min, troostite will occur, and if it exceeds 100°C/min, cracks will easily occur on the inner surface of the lining layer.

Next, as shown in C, in the holding step, the region where bainite transformation occurs is 300 to 550°C.

If the temperature is less than 300°C in which bainite transformation occurs, cracks are likely to occur on the inner surface of the lining layer due to transformation expansion of the cylinder base material at low temperatures, and if it exceeds 550°C, pearlite is formed.

Further, the holding time in the holding step is 10 minutes or more. If the holding time is less than 10 minutes, the amount of bainite in the cylinder base material will be less than 20%, and sufficient strength will not be obtained.

Next, heating is performed to the annealing temperature as shown in D.
At this time, the heating rate is 1~10''C/min.

If the heating rate is less than 1°C/min, the amount of bainite in the cylinder base material will be excessive, and cracks will easily occur on the inner surface of the lining layer. On the other hand, if the heating rate exceeds 10° C./min, the amount of bainite becomes insufficient and strength cannot be obtained.

Then, annealing is performed as shown in E, at an annealing temperature of 550 to 650°C. Annealing temperature is 5
If the temperature is less than 50°C, the purpose of annealing to remove residual stress will not be achieved, and if it exceeds 650°C, the metal structure will be affected.

Further, the annealing time is 1 to 5 hours. If the annealing time is less than 1 hour, the residual stress cannot be removed sufficiently, and even if the annealing time exceeds 5 hours, there is no significant change in the effect.

Finally, as shown in F, it is cooled to room temperature.

The composite cylinder of this example formed as described above has a structure in which the lining layer has excellent fatigue strength, particularly crack resistance, since the strength of the cylinder base material is significantly improved.

The present invention will be explained in detail with reference to the following specific examples.

Example 1 A joined body having the structure shown in FIG. 2 was produced by the method described above, but Cr7.
0% by weight, 82.5% by weight, Si2.7% by weight, Co1
An atomized powder of an alloy consisting of 0.0% by weight of Fe, 0.5% by weight of Fe, and the remainder substantially Ni and unavoidable impurities was used, and SCM440 was used as the cylinder base material.

In addition, the above bonded body was subjected to HIP treatment in a HIP apparatus having a structure as shown in FIG.
The processing conditions were: Ar gas atmosphere, temperature 950°C, pressure 1. OOOatm for 4 hours to obtain a composite cylinder.

Example 2 In the same manner as in Example 1, a bonded body was produced, or as an alloy material forming a lining layer, 7.0% by weight of Cr and B 2 were used.
．． 5% by weight, Si2.7% by weight, Co10.0% by weight,
An atomized powder of an alloy consisting of 0.5% by weight of Fe, the balance substantially Ni and unavoidable impurities, and further 100% of atomized powder with a particle size of 5 to 30i JXl fine particles made of WC.
20 parts by weight per part by weight were uniformly dispersed. Furthermore, SNCM439 was used as the cylinder base material.

Next, the atomized powder and the sealed bonded body are transferred to a third
Load it into the HIP device with the structure shown in the figure, and HIP it.
Processed. The HIP processing conditions at this time are a temperature of 950
A composite cylinder was obtained by carrying out the process for 4 hours at a pressure of 11,000 at.degree. C. and an Ar inert gas atmosphere.

Example 3 A composite cylinder similar to Example 1 was further subjected to heat treatment.

The heat treatment conditions at this time were: heating temperature 900°C (A shown in Figure 4), cooling rate 80°C/min (B shown in Figure 4),
Temperature that causes bainite transformation: 500°C 1 Holding time: 20
minutes (C shown in Figure 4), heating rate 5°C/min (D shown in Figure 4), annealing temperature 630°C, holding time 5 hours (C shown in Figure 4).
E) shown in the figure.

The structure of the cylinder base material of the composite cylinder thus formed consisted of about 50% bainite and about 50% sorbite.

Example 4 A composite cylinder similar to Example 2 was further subjected to heat treatment.

The heat treatment conditions at this time were: initial temperature (A shown in Figure 4);
Cooling rate 50°C/min (B shown in Figure 4), temperature at which bainite transformation occurs 50°C, holding time 20 minutes (C shown in Figure 4), heating rate 5°C/min (D shown in Figure 4) ), the annealing temperature was 630° C., and the holding time was 5 hours (E shown in FIG. 4).

The structure of the cylinder base material of the composite cylinder thus formed consisted of about 20% bainite and about 80% sorbite.

Regarding the composite cylinder of this example described above, the wear resistance and corrosion resistance of the lining layer and the strength of the cylinder base material were measured.

Regarding wear resistance, 10mm from the molding machine cylinder
Create a sample with a size of 15mm x 10mm, and
400 abrasive paper with a load of 2.0 kg, 480 m
The amount of wear on the lining material was examined after it had been slid over a distance of .

This result was expressed as a relative value when the result of a comparative example described later was set as 1.0, and the wear resistance was evaluated.

Regarding corrosion resistance, a sample was prepared from a cylinder for a molding machine, and after being immersed in a 10% HCI aqueous solution at 50°C for 24 hours, the amount ratio of corrosive raw material in the lining material was examined.

This result was expressed as a relative value when the result of the comparative example described later was set as 10, and the corrosiveness was evaluated.

Regarding the strength of the cylinder base material, a tensile test sample was prepared from the base material, a tensile test was conducted, and the 0.2% yield strength, which is the most important strength of the base material, was measured.

These results are shown in Table 1.

As is clear from Table 1, in the composite cylinder of Example 1.2, the lining layer had excellent wear resistance and corrosion resistance.

Furthermore, it can be seen that in the composite cylinders of Examples 3 and 4, the strength of the cylinder base material was significantly improved due to the appropriate heat treatment. Therefore, it is thought that the strain applied to the lining layer is reduced, and fatigue strength and crack resistance are improved.

Although the present embodiment has been described using a composite cylinder of an axle as an example, it is also possible to use a composite cylinder of a plurality of axles, and it goes without saying that good effects can be achieved in this case as well.

Further, in this embodiment, an example has been described in which the core metal of the composite cylinder has a hollow structure, but it goes without saying that a good effect can be obtained even if a core metal of a solid structure is used.

〔Effect of the invention〕

As detailed above, in the composite cylinder of the present invention, the lining layer is formed of an alloy material having an optimal composition for adding the above-mentioned corrosion resistance and wear resistance, and the alloy material is formed by a HIP process. It has a structure that is pressure sintered to the cylinder base material. Therefore, the lining layer is coated without Fe entering from the cylinder base material, resulting in a structure having excellent wear resistance and corrosion resistance.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view showing the state in which the core metal is inserted into the cylinder base material, Fig. 2 is a schematic cross-sectional view showing the state in which the cylinder is filled with alloy powder for lining, and Fig. 3 is a schematic cross-sectional view showing the state in which the core metal is inserted into the cylinder base material. FIG. 4 is a schematic sectional view showing a HIP apparatus for manufacturing a composite cylinder of the present invention, and FIG. 4 is a diagram of a heat treatment pattern of a composite cylinder according to an embodiment of the present invention. ■・・・・・・Cylinder base material 2・・・・・・Core metal 3・・・・・・Hollow part 3a・・・Alloy powder 4.5.8・・・Lid 7...HIP device 3L 32... End 41... Hopper opening

Claims (1)

Scope of Claims: (1) A composite cylinder having a lining layer and a cylinder base material layer, wherein the lining layer has Cr5.0 to 2.
0.0% by weight, B2.5~4.0% by weight, Si2.5~
10.0% by weight, Co5.0-40.0% by weight, Fe5
．． 1. A composite cylinder, characterized in that an atomized powder of an alloy containing 0% by weight or less, the balance substantially consisting of Ni and unavoidable impurities, is pressure sintered on the inner surface of the cylinder base material by a HIP process. (2) In the composite cylinder according to claim 1, the lining layer comprises, per 100 parts by weight of the atomized powder,
1. A composite cylinder comprising 5 to 60 parts by weight of fine particles of a carbide of an element belonging to Group IVa, Group Va, or Group VIa uniformly dispersed therein. (3) The composite cylinder according to claim 2, wherein the fine particles made of the carbide have a particle size of 5 to 100 μm. (4) In the composite cylinder according to any one of claims 1 to 3, the structure of the cylinder base material is bainite 20,
% or more, the balance being sorbite. (5) In the composite cylinder according to claim 4, the cylinder base material contains 0.3 to 0.5% by weight of C, S
i0.15 to 0.35 wt%, Mn0.3 to 1.5 wt%, P0.03 wt% or less, S0.03 wt% or less, C
r0.7-1.5% by weight, Mo0.1-0.5% by weight,
The remainder essentially consists of Fe and unavoidable impurities Cr-M
A composite cylinder characterized by being made of steel. (6) In the composite cylinder according to claim 4, the cylinder base material includes C0.3 to 0.5% by weight, Si0.15
~0.35% by weight, Mn0.3-1.5% by weight, P0.
03% by weight or less, S 0.03% by weight or less, Ni 3.0% by weight or less, Cr 0.7-1.5% by weight, Mo 0.1-0
．． 1. A composite cylinder comprising Ni-Cr-Mo steel consisting of 5% by weight and the remainder substantially Fe and unavoidable impurities.