JP3254909B2 - Internal-combustion engine tappet member having high joining strength with chip material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, tappet members of internal combustion engines such as diesel engines and gasoline engines have been generally used.
For example, as described in Japanese Patent Application Laid-Open No. Sho 62-182406 and illustrated in a schematic longitudinal sectional view in FIG. 1, a tappet body usually formed by cold forging and made of carbon steel, alloy steel, or the like. And at least one of metal carbides, nitrides, and borides and N
There is known a tappet member formed by joining a chip material 2 made of an i or Ni alloy simultaneously with liquid phase sintering thereof.

[0003]

On the other hand, in recent years, the output and performance of an internal combustion engine have been remarkably increased, and accordingly, the tappet member, which is a structural member of the internal combustion engine, has been used under more severe conditions. In the conventional tappet member described above, the bonding strength between the tappet body and the tip material is not sufficient in the above-described conventional tappet member, so that under severe operating conditions, peeling is apt to occur between the two, and the reliability is low. There is a problem in the point.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, the above-mentioned conventional tappet member was focused on, and as a result of researching to improve the joining strength of the tip material constituting the tappet member to the tappet body, the tappet body was weight% (hereinafter, referred to as “weight”). % Indicates% by weight), C: 0.
13-0.5%, Si: 0.15-0.35%,
Mn: 0.3-1.2%, Cr: 0.4-3.5
%, And optionally, Ni: 0.4 to
4.5%, Mo: 0.15 to 0.7%, one or two of which are specified, and the remainder is specified as a low alloy steel having a composition consisting of Fe and unavoidable impurities, and On the top surface on the cam contact surface side, the compounding composition of the green compact before sintering of the chip material to be joined simultaneously with sintering is represented by Co: 20 to 30.
%, Ni: 3 to 15% (however, Co + N
i: 25~35%), P: 0.1~1%, chromium carbide (hereinafter, indicated by _{Cr 3 C 2): 0.1~10%} , optionally Fe: 0.1 to 3%, WC: When the tip material is sintered, the S
The interaction between i and P constituting the tip material significantly improves the wettability of the tip material to the tappet body, and the effect of Cr ₃ C ₂ dissolved in Co + Ni constituting the bonding phase of the tip material. As a result, the adhesiveness of the tip material to the tappet body is remarkably improved, and as a result, the tip material after sintering becomes extremely firmly bonded to the tappet body, and is substantially composed of a WC-based cemented carbide. As a result, the research result of having excellent wear resistance was obtained.

[0005] The present invention has been made based on the above research results, wherein C: 0.13 to 0.5%,
Si: 0.15 to 0.35%, Mn: 0.3 to 1.2
%, Cr: 0.4-3.5%, and if necessary, Ni: 0.4-4.5%, Mo:
0.15 to 0.7% of the low-alloy steel tappet body containing one or two of the following components and having a balance of Fe and inevitable impurities, As a chip material, Co: 20 to 30%, Ni: 3 to
15% (however, Co + Ni: 25 to 35%) P:
Liquid phase sinter bonding of a green compact having a composition of 0.1 to 1%, Cr ₃ C ₂ : 0.1 to 10%, Fe: 0.1 to 3% as needed, WC: remaining The tapping member is characterized in that the tip material has a high joining strength.

Next, in the tappet member of the present invention, the reason why the component composition of the tappet body and the compounding composition of the tipping material are limited as described above will be described. A. Ingredient Composition of Tappet Body (a) C The C component has a function of improving the strength by forming a solid solution in a base material. However, if the content is less than 0.13%, a desired strength improving effect cannot be obtained. If the content exceeds 0.5%, the toughness will decrease.
It was determined to be 13 to 0.5%. Preferably, 0.2 to
The content of 0.3% is good.

(B) Si The Si component improves the wettability with the tip material by the coexistence of P in the tip material during sintering of the tip material, thereby improving the adhesion of the tip material to the tappet body. When the content is less than 0.15%, the desired effect cannot be obtained in the above-mentioned effect, while when the content exceeds 0.35%, the strength is reduced. The content was determined to be 0.15 to 0.35%. Desirably 0.2 ~
The content of 0.3% is good.

(C) Mn The Mn component has a function of improving the toughness by forming a solid solution in the base material, but if its content is less than 0.3%, the desired effect of improving the toughness cannot be obtained. If the amount exceeds 1.2%, the strength rapidly decreases, so the content was determined to be 0.3 to 1.2%. Desirably 0.7-1%
Is good.

(D) Cr The Cr component has a function of improving the heat resistance by forming a solid solution in the base material, but if its content is less than 0.4%, the desired effect of improving the heat resistance cannot be obtained. If the content exceeds 3.5%, the toughness will decrease, so the content was determined to be 0.4 to 3.5%. Preferably, 1-3%
Is good.

(E) Ni and Mo Since these components have a function of further improving the strength by forming a solid solution in the base material, they are contained as necessary. Less than 4% and Mo:
If it is less than 0.15%, the desired effect of improving the strength cannot be obtained, while if its content exceeds 4.5% Ni and 0.7% Mo, the toughness is reduced. Ni: 0.4 to 4.5%, Mo: 0.15 to 0.7
%. Preferably, Ni: 2-3%, Mo:
The content is preferably 0.3 to 0.5%.

B. Composition of chip material (a) Co The Co component is an essential component for enabling sintering and ensuring toughness, but if its ratio is less than 20%, the desired effect can be obtained in the above-mentioned operation. On the other hand, if the ratio exceeds 30%, the hardness decreases, so the ratio is set to 20 to 30%. The ratio is preferably 23 to 25%.

(B) Ni The Ni component has an effect of improving the strength in the coexistence with the Co component. However, if the proportion is less than 3%, the desired effect of improving the strength cannot be obtained. Is 2
If it is less than 5%, the desired effects of the above-mentioned effects of Co and Ni cannot be obtained. On the other hand, if the proportion of Ni exceeds 15%, the toughness decreases, and in this case, the total amount of Ni and Co is 35%. Is exceeded, the abrasion resistance is reduced, so that the Ni content is 3 to 15%, preferably 5 to 7%.
%, The total amount of Ni and Co is 25 to 35%, preferably 28
３２32%.

(C) For the PP component, the sinterability is improved to enable liquid phase sintering, and the wettability of the tip material to the tappet body is improved by the coexistence of Si with the tappet body. If the ratio is less than 0.1%, the desired effect cannot be obtained, whereas if the ratio exceeds 1%, an embrittlement phenomenon appears. 1-1%
It was decided. The ratio is preferably 0.3 to 0.7%.

(D) The Cr ₃ C ₂ Cr ₃ C ₂ component forms a solid solution with the binder phase and, together with the effect of improving the wettability by Si of the tappet body and P of the tip material, makes the tip material adhere to the tappet body. However, if the ratio is less than 0.1%, the desired effect cannot be obtained, and if the ratio exceeds 10%, the strength is reduced. The ratio was defined as 0.5-10%. Desirably, the ratio is 4 to 8%.

(E) Fe The Fe component forms a solid solution in the binder phase and has the effect of improving its hardness. Therefore, the Fe component is contained as necessary. Since the desired effect of improving the hardness cannot be obtained, and if the ratio exceeds 3%, the strength decreases, the ratio is set to 0.1 to 3%. Desirably, the ratio is 0.3 to 1%.

[0016]

Next, the tappet member of the present invention will be specifically described with reference to examples. First of all, the shape and outer diameter shown in FIG. 1 by cold forging were: 31 mm × length: 5
To prepare tappet bodies A to P having a dimension of 1 mm and made of low alloy steel having the component compositions shown in Table 1, respectively, and as a raw material powder for forming a chip material,
WC powder with a particle size of 100 mesh or less, Cr ₃
C ₂ powder, Co-P alloy (containing 35% P) powder, Fe
-Using a P alloy (containing 25% P) powder, Fe powder, Co powder, Ni powder and graphite powder, blending these raw material powders in the blending composition shown in Table 2 and mixing,
The compacts a to q having dimensions of diameter: 31 mm ^φ × thickness: 3 mm are press-formed at a pressure of / cm ² , and these compacts a to q are compacted.
q is a combination of tappet bodies A in the combinations shown in Table 3, respectively.
ＰP is placed on the top surface on the cam contact surface side as shown in the figure, and in this state, the green compact is held under vacuum at a predetermined temperature in the range of 1200 to 1300 ° C. for 60 minutes. By sintering to a chip material and joining it to the tappet body, tappet members 1 to 15 of the present invention and comparative tappet members 1 to 5 were manufactured, respectively.

The comparative tappet members 1 to 5 are components that affect the bonding strength between the tappet body and the tip material, that is, Si of the tappet body and P and Cr of the tip material.
The content ratio of any one of ₃ C ₂ is out of the range of the present invention.

Next, the Vickers hardness of the tip material was measured for the various tappet members obtained as a result, and this was incorporated into a 6-cylinder, 12-valve, 8200 cc, 210 hp diesel engine.
pm, operation time: 200 hours of high-speed rotation conditions, actual machine tests were performed to measure the maximum wear depth of the tip material on the cam sliding surface and to evaluate the joining strength of the tip material to the tappet body. The joint surface between the two was observed along the outer periphery, and the number of cracks caused by peeling was measured. Further, for the purpose of evaluating the bonding strength, the shear strength of the bonding surface was also measured. Table 3 shows the results of these measurements.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

As can be seen from the results shown in Tables 1 to 3, the tappet members 1 to 15 of the present invention have excellent abrasion resistance without causing a peeling phenomenon of the tip material from the tappet body despite high-speed operation. As shown in the comparative tappet members 1 to 5, any one of Si of the tappet body and P and Cr ₃ C ₂ of the tip material, which greatly affect the joining between the tappet body and the tip material, as shown in the comparative tappet members 1 to 5. 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 constituting this is remarkably firmly joined to the top surface of the tappet body on the side of the cam abutting surface, it can sufficiently cope with high speed and high performance of the internal combustion engine, and is excellent for a long time. It demonstrates its performance.

[Brief description of the drawings]

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

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C22C 38/18 C22C 38/18 F01L 1/14 F01L 1/14 B // B23K 103: 18 B23K 103: 18 (56) References JP-A-60-39149 (JP, A) JP-A-4-132806 (JP, A) JP-A-3-294452 (JP, A) JP-A-50-9148 (JP, A) JP-A-53-80319 (JP, A) JP-A-60-63349 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22F ⁷ /00-7/08 B23K 20/00-20/227 F01L 1 /14

Claims (4)

(57) [Claims] C .: 0.13 to 0.5%, Si: 0.15 to 0.5% by weight.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, And the remainder is composed of a low-alloy steel tappet body having a composition consisting of Fe and unavoidable impurities.
As a chip material, Co: 20 to 30%, Ni: 3 to 15%, (however, Co + Ni: 25 to 35%), P: 0.1 to 1%, chromium carbide: 0.5 to
10%, tungsten carbide: a tappet member for an internal combustion engine having a high joining strength, formed by liquid phase sintering a compact having a composition of: 2. C .: 0.13-0.5% by weight, Si: 0.15-0.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, Ni: 0.4-4.5%, Mo: 0.15-0.4%.
7%, one or two of the following, and the remainder is composed of a low-alloy steel tappet body having a composition consisting of Fe and unavoidable impurities.
As a chip material, Co: 20 to 30%, Ni: 3 to 15%, (however, Co + Ni: 25 to 35%) P: 0.1 to 1%, chromium carbide: 0.1 to
10%, tungsten carbide: a tappet member for an internal combustion engine having a high joining strength, formed by liquid phase sintering a compact having a composition of: C .: 0.13 to 0.5%, Si: 0.15 to 0.5% by weight.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, And the remainder is composed of a low-alloy steel tappet body having a composition consisting of Fe and unavoidable impurities.
As a chip material, Co: 20 to 30%, Ni: 3 to 15%, (however, Co + Ni: 25 to 35%), P: 0.1 to 1%, chromium carbide: 0.1 to
An internal combustion engine tappet member having a high joining strength with a chip material formed by liquid phase sintering of a compact having a composition of 10%, Fe: 0.1 to 3%, tungsten carbide: remaining. 4. C .: 0.13 to 0.5% by weight, Si: 0.15 to 0.5% by weight.
35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5
%, Ni: 0.4 to 4.5%, Mo: 0.15 to 0.5%.
7%, one or two of the following, and the remainder is composed of a low-alloy steel tappet body having a composition consisting of Fe and unavoidable impurities.
As a chip material, Co: 20 to 30%, Ni: 3 to 15%, (however, Co + Ni: 25 to 35%) P: 0.1 to 1%, chromium carbide: 0.1 to
An internal combustion engine tappet member having a high joining strength with a chip material formed by liquid phase sintering of a compact having a composition of 10%, Fe: 0.1 to 3%, tungsten carbide: remaining.