JPH07332032A - Internal combustion engine tappet member provided with tip material having high bonding strength - Google Patents

Abstract

PURPOSE:To provide an internal combustion engine tappet member in which a tip material is provided with high bonding strength. CONSTITUTION:A tappet member contains 0.13-0.5% by weight of C, 0.15-0.35% by weight of Si, 0.3-1.2% by weight of Mn, and 0.4-3.5% by weight of Cr, and as required, one or two kinds of substances among 0.4-4.5% by weight of Ni and 0.15-0.7% by weight of Mo is contained. On a top face 1a on a cam contact face side of a low alloy steel tappet main body 1 provided with the composition in which the rest consists of Fe and unavoidable impurities, a green compact whose compound composition is comprised of 25-35% of Co, 0.1-1% of P, 0.1-7% of one kind or two or more kinds of substance/substances among NbC, VC, TiC, Mo2C, and TaC, 0.1-3% of Fe as required, and the rest of WC is connected as a tip material 2 in a way of liquid phase sintering bonding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a chip material made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide, which is solid-phased on a low alloy steel tappet body simultaneously with liquid phase sintering of the chip material. The present invention relates to an internal combustion engine tappet member that is joined with a joining strength.

[0002]

2. Description of the Related Art Conventionally, as a tappet member for an internal combustion engine such as a diesel engine or a gasoline engine,
For example, as described in Japanese Patent Application Laid-Open No. 62-182406, and as illustrated in a schematic longitudinal sectional view in FIG. 1, a tappet body normally formed by cold forging and made of carbon steel or alloy steel. On the top surface 1a on the cam contact surface side of No. 1, one or more of metal carbide, nitride and boride and N
A tappet member is known in which a chip material 2 composed of an i or Ni alloy is joined at the same time as liquid phase sintering.

[0003]

On the other hand, in recent years, high output and high performance of internal combustion engines have been remarkable, and along with this, tappet members, which are structural members thereof, are required to be used under even more severe conditions. Although there is a tendency to be forced, because the conventional tappet member described above does not have sufficient bonding strength between the tappet body and the chip material, under severe conditions of use, peeling easily occurs between them, and reliability is high. There is a problem with.

[0004]

Therefore, the present inventors have
From the viewpoint as described above, focusing on the conventional tappet member, as a result of research to improve the bonding strength of the tip material forming the tappet body to the tappet body, the tappet body in% by weight (hereinafter, % Indicates% by weight), C: 0.
13-0.5%, Si: 0.15-0.35%,
Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, And if necessary, Ni: 0.4-
4.5%, Mo: 0.15 to 0.7%, one or two kinds, and the rest is specified as a low alloy steel having a composition of Fe and inevitable impurities. The compounding composition of the green compact before sintering of the chip material to be joined at the same time as sintering on the top surface of the cam contact surface side is Co: 25-30
%, P: 0.1 to 1%, Nb, V, Ti,
Carbides of Mo and Ta (hereinafter NbC, V, respectively)
C, TiC, Mo ₂ C, and TaC, which are collectively referred to as metal carbides), or two or more kinds: 0.1 to 7%, and optionally Fe: 0.1 to 3 %,
WC: When the tip material is specified, when the tip material is sintered, the wettability of the tip material to the tappet body is significantly improved due to the interaction between Si of the tappet body and P constituting the tip material. , The adhesion of the tip material to the tappet body is significantly improved by the action of the metal carbide dissolved in Co that constitutes the binder phase of the tip material, and as a result, the sintered tip material is extremely strong in the tappet body. The research results indicate that the alloy has excellent wear resistance because it comes to be joined and is substantially composed of a WC-based cemented carbide.

The present invention was made based on the above research results, and C: 0.13 to 0.5%,
Si: 0.15 to 0.35%, Mn: 0.3 to 1.2
%, Cr: 0.4 to 3.5%, and, if necessary, Ni: 0.4 to 4.5%, Mo:
0.15 to 0.7%, one or two of 0.1 to 0.7%, and the balance being a composition consisting of Fe and unavoidable impurities, the top surface of the low alloy steel tappet body on the cam contact surface side, As a chip material, Co: 25 to 35%, P: 0.1
~ 1%, one or more of metal carbides: 0.
1 to 7%, optionally Fe: 0.1 to 3%, WC: balance, which is obtained by liquid-phase sintering joining a green compact having a compounding composition, and a chip material having a high joining strength It is characterized by a tappet member.

Next, the reason why the composition of the tappet body and the composition of the chip material in the tappet member of the present invention are limited as described above will be explained. A. Component composition of the tappet body (a) CC component has a function of forming a solid solution in the matrix to improve strength, but if the content thereof is less than 0.13%, the desired strength improving effect cannot be obtained. If the content exceeds 0.5%, the toughness is reduced, so the content is set to 0.
It was set to 13 to 0.5%. In addition, desirably 0.2
0.4% content is good.

(B) Si The Si component improves the wettability with the chip material due to the coexisting action with P in the chip material during the sintering of the chip material, thereby improving the adhesion of the chip material to the tappet body. Although there is an effect of improving the strength, if the content is less than 0.15%, the desired effect cannot be obtained, and if the content exceeds 0.35%, the strength decreases. The content was set to 0.15 to 0.35%. Desirably 0.2-
0.3% content is good.

(C) Mn The Mn component has the action of forming a solid solution in the matrix to improve the toughness, but if its content is less than 0.3%, the desired toughness improving effect cannot be obtained. When the amount exceeds 1.2%, the strength rapidly decreases, so the content was set to 0.3 to 1.2%. Desirably 0.7-1%
Is included.

(D) Cr The Cr component has the function of forming a solid solution in the matrix to improve the heat resistance, but if the content of Cr is less than 0.4%, the desired heat resistance improving effect cannot be obtained. When the content exceeds 3.5%, the toughness decreases, so the content was set to 0.4 to 3.5%. In addition, desirably 1-3%
Is included.

(E) Ni and Mo These components have the action of forming a solid solution in the base material to further improve the strength, so that they are contained as necessary, but their contents are Ni: 0. Less than 4% and Mo:
If it is less than 0.15%, the desired strength-improving effect cannot be obtained. On the other hand, if the content exceeds Ni: 4.5% and Mo: 0.7%, the toughness tends to decrease. Ni: 0.4-4.5%, Mo: 0.15-0.7
Defined as%. Desirably, Ni: 2-3%, Mo:
The content of 0.3 to 0.5% is preferable.

B. Compounding composition of chip material (a) Co The Co component has an action of forming a binder phase to improve strength and toughness, but if the proportion is less than 25%, the desired effect cannot be obtained in the above action. On the other hand, when the ratio exceeds 35%, the hardness sharply decreases and the wear resistance is unavoidably deteriorated. Therefore, the ratio is set to 25 to 30%. In addition,
Desirably, the ratio is 28 to 32%.

(B) The P P component improves the sinterability and enables liquid phase sintering, and also improves the wettability of the tip material to the tappet body by the coexisting action with Si of the tappet body. There is an effect, but if the ratio is less than 0.1%, the desired effect cannot be obtained, and if the ratio exceeds 1%, an embrittlement phenomenon appears. 1-1%
I decided. In addition, the ratio of 0.3 to 0.7% is desirable.

(C) Metal Carbide The metal carbide is solid-solved in the binder phase and forms Si in the tappet body.
In addition to the wettability improving effect of P of the chip material,
Although it has the effect of significantly improving the adhesion of the chip material to the tappet body, if the ratio is less than 0.1% the desired effect is not obtained, while if the ratio exceeds 7% the strength decreases. Therefore, the ratio is 0.1
It was set at ~ 7%. It should be noted that the proportion of 0.5 to 3% is desirable.

(E) Fe The Fe component has the function of forming a solid solution in the binder phase and improving the hardness thereof, so it is contained if necessary, but if the proportion is less than 0.1%. The desired hardness improving effect is not obtained, and the strength exceeds 3%, and the strength decreases. Therefore, the ratio is set to 0.1 to 3%. Desirably, the ratio is 0.3 to 1%.

[0015]

EXAMPLES Next, the tappet member of the present invention will be specifically described by way of examples. First of all, the shape and outer diameter shown in FIG. 1 and the outer diameter: 31 mm × length: 5 are all obtained by cold forging
To prepare tappet bodies A to P each having a size of 1 mm and composed of low alloy steel having the composition shown in Table 1, as raw material powder for forming a chip material,
All of them have a grain size of 100 mesh or less, WC powder, metal carbide powder, Co-P alloy (P: 35% content) powder, Fe.
-P alloy (P: 25% content) powder, Fe powder, Co powder, and graphite powder were used, and these raw material powders were blended to the blending composition shown in Table 2 and mixed, and then at a pressure of 5 ton / cm ² . Diameter: 31 mm ^φ × thickness: 3 mm of green compacts a to q are press-molded, and these green compacts a to q are combined in the respective combinations shown in Table 3 and the cams of the tappet bodies A to P are combined. Place it on the top surface of the contact surface side as shown, and in this state,
The tappet member 1 of the present invention is obtained by sintering the green compact into a chip material under the condition of holding at a predetermined temperature within a range of 1200 to 1300 ° C. in vacuum for 60 minutes, and joining the chip material to a tappet body. ~ 15 and comparative tappet member 1
~ 5 were produced respectively.

In the comparative tappet members 1 to 5, the components that affect the bonding strength between the tappet body and the tip material, that is, the content ratio of any of Si of the tappet body, P of the tip material and metal carbide, This is outside the scope of the present invention.

Next, with respect to various tappet members obtained as a result, the Vickers hardness of the tip material was measured, and the Vickers hardness was incorporated into a 6-cylinder 12-valve, 8200 cc, 210-hp diesel engine at a rotational speed of 3000 r.
pm, operating time: 200 hours of high-speed rotation, the actual machine test is performed to measure the maximum wear depth on the cam sliding surface of the tip material and to evaluate the bonding strength of the tip material to the tappet body. The joint surfaces of both were observed along the outer circumference, and the number of cracks caused by peeling was measured. Further, for the purpose of evaluating the joint strength, the shear strength of the joint surface was also measured. The results of these measurements are shown in Table 3.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

From the results shown in Tables 1 to 3, the tappet members 1 to 15 of the present invention have excellent wear resistance without causing the chipping phenomenon of the chip material from the tappet body, despite the high speed operation. On the other hand, as shown in Comparative tappet members 1 to 5, any one of Si of the tappet body and P of the tip material and metal carbide which has a great influence on the joining of the tappet body and the tip material is exhibited. It is clear that if the content ratio deviates from the range of the present invention to the lower side, a strong bonding strength cannot be secured to them. As described above, the tappet member of the present invention,
Since the tip material that constitutes this is remarkably strongly bonded to the top surface of the tappet body on the side of the cam contact surface, it can sufficiently satisfy the high speed and high performance of the internal combustion engine and is excellent for a long time. It exerts its performance.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view illustrating a tappet member of an internal combustion engine.

[Explanation of symbols]

 1 Tappet body, 1a Top surface of the tappet body on the side of the cam contact surface, 2 Tip materials.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C22C 38/44

Claims (4)

[Claims] 1. C: 0.13 to 0.5% by weight, Si: 0.15 to 0.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, With the balance being Fe and unavoidable impurities and having a composition of Fe and unavoidable impurities, on the top surface of the cam contact surface side of the low alloy steel tappet body, as a chip material, Co: 25 to 35%, P: 0.1 ~ 1%, one of Nb, V, Ti, Mo, and Ta carbides
1 or 2 or more kinds: 0.1 to 7%, tungsten carbide: the remainder, an internal combustion engine tappet member having a high bonding strength of a chip material, which is formed by liquid phase sintering bonding of a powder compact having a compounding composition. 2. C: 0.13 to 0.5%, Si: 0.15 to 0.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, Ni: 0.4-4.5%, Mo: 0.15-0.
7%, one or two of them, and the balance Fe
On the top surface of the low alloy steel tappet body having a composition of unavoidable impurities and the cam contact surface side, as a chip material, Co: 25 to 35%, P: 0.1 to 1%,
One of Nb, V, Ti, Mo, and Ta carbides
1 or 2 or more kinds: 0.1 to 7%, tungsten carbide: the remainder, an internal combustion engine tappet member having a high bonding strength of a chip material, which is formed by liquid phase sintering bonding of a powder compact having a compounding composition. 3. By weight%, C: 0.13 to 0.5%, Si: 0.15 to 0.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, With the balance being Fe and unavoidable impurities and having a composition of Fe and unavoidable impurities, on the top surface of the cam contact surface side of the low alloy steel tappet body, as a chip material, Co: 25 to 35%, P: 0.1 ~ 1%, one of Nb, V, Ti, Mo, and Ta carbides
Type or two or more types: 0.1 to 7%, Fe: 0.1 to 3%, tungsten carbide: the remainder, which is formed by liquid phase sintering joining of a powder compact having a compounding composition, and has a high chip material. A strong internal combustion engine tappet member. 4. By weight%, C: 0.13 to 0.5%, Si: 0.15 to 0.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, Ni: 0.4-4.5%, Mo: 0.15-0.
7%, one or two of them, and the balance Fe
On the top surface of the cam contact surface side of the low alloy steel tappet body having a composition consisting of and unavoidable impurities, as a chip material, Co: 25 to 35%, P: 0.1 to 1%, Nb, V, Ti One of the carbides of Mo, Mo, and Ta
Type or two or more types: 0.1 to 7%, Fe: 0.1 to 3%, tungsten carbide: the remainder, which is formed by liquid phase sintering joining of a powder compact having a compounding composition, and has a high chip material. A strong internal combustion engine tappet member.