JP3230127B2 - 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 at the same time as a 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-mentioned 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 reduced by weight% (hereinafter, referred to as % 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 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 +
Ni: 25 to 35%), P: 0.1 to 1%, Nb, V,
Carbides of Ti, Mo, and Ta (hereinafter referred to as Nb, respectively)
C, VC, TiC, Mo ₂ C, and TaC, which are collectively referred to as metal carbides):
0.1-7%, if necessary Fe: 0.1-3%, W
C: When the tip material is specified, the wettability of the tip material to the tappet body is significantly improved by the interaction between Si of the tappet body and P constituting the tip material when the tip material is sintered. The adhesion of the tip material to the tappet body is remarkably improved by the action of the metal carbide dissolved in Co + Ni constituting the bonding phase of the tip material. As a result, the tip material after sintering is extremely firmly attached to the tappet body. Since they came to be joined and consisted substantially of a WC-based cemented carbide, they obtained a research result that they also had excellent wear resistance.

[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 to 3.5%, and if necessary, Ni: 0.4 to 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:
0.1 to 1%, one or more of metal carbides: 0.1 to 7%, if necessary, Fe: 0.1 to 3%,
WC: The tip material is characterized by being a tappet member of an internal combustion engine having a high bonding strength, formed by liquid phase sintering of a green compact having a compounding composition consisting of the remainder.

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 to
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 dissolving in the base material to further improve the strength, they are contained as necessary. Less than 4% and Mo:
If the content 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 is reduced. Ni: 0.4 to 4.5%, Mo: 0.15 to 0.7
%. Preferably, Ni: 2-3%, Mo:
The content of 0.3 to 0.5% is good.

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%. Preferably, the ratio is 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 to 35%.
It was determined to be 32%.

(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) Metal Carbide Metal carbide contains solid solution in the binder phase and contains Si
And the effect of improving the wettability by the P of the chip material,
It has the effect of significantly improving the adhesion of the tip material to the tappet body. However, if the proportion is less than 0.1%, the desired effect cannot be obtained, whereas if the proportion exceeds 10%, the strength decreases. The ratio is set to 0.
5-10% was determined. 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 the strength whose ratio exceeds 3% 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 and outer diameter: 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, various metal carbide powders, Co-P alloy (P: 35% content) powder,
Fe-P alloy (P: 25% content) powder, Fe powder, Co
Using powder, Ni powder, and graphite powder, these raw material powders were blended into the blending composition shown in Table 2, mixed, and then mixed.
The green compacts a to q having the dimensions of diameter: 31 mm ^φ × thickness: 3 mm are press-molded at a pressure of ton / cm ² , and these green compacts a to q are combined in the combinations shown in Table 3 respectively. Placed on the top surface of the tappet bodies A to P on the cam contact surface side as shown,
In this state, the green compact is sintered into a chip material under a condition of holding at a predetermined temperature in a range of 1200 to 1300 ° C. for 60 minutes in a vacuum, and this is bonded to a tappet body to form a chip. Inventive tappet members 1 to 15 and comparative tappet members 1 to 5 were manufactured, respectively.

The comparative tappet members 1 to 5 have components which affect the bonding strength between the tappet body and the tip material, that is, the content ratio of Si of the tappet body and any one of P and metal carbide in the tip material. It falls outside the scope 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 assembled in a 6-cylinder, 12-valve, 8200 cc, 210 horsepower diesel engine, and the number of revolutions was 3000 rpm.
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. In contrast, as shown in the comparative tappet members 1 to 5, any one of Si in the tappet body, P in the tip material, and metal carbide, which greatly affect the joining between the tappet body and the tip material, as seen in the comparative tappet members 1 to 5 If the content is out of the range of the present invention, it is apparent that a strong bonding strength cannot be secured to them. As described above, according to the tappet member of the present invention, the tip member constituting the tappet member is extremely strongly bonded to the top surface of the tappet body on the cam contact surface side, so that the speed and performance of the internal combustion engine can be improved. They can respond satisfactorily and exhibit excellent performance over the long term.

[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 38/44 C22C 38/44 F01L 1/14 F01L 1/14 B // B23K 103: 18 B23K 103: 18 (56) References JP-A-4-132806 (JP, A) JP-A-3-294452 (JP, A) JP-A-60-63349 (JP, A) JP-A-59-9148 (JP, A) JP-A-53-80319 (JP, A) JP-A-60-39149 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 20/00-20/227 B22F ⁷ /00-7/08 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
%, The balance being Fe and unavoidable impurities, the tip surface of the low alloy steel tappet body on the cam contact surface side as a tip material, Co: 20 to 30%, Ni: 3 to 15 % (However, Co + Ni: 25 to 35%), P: 0.1 to 1%, and one of carbides of Nb, V, Ti, Mo, and Ta
One or more kinds: 0.1 to 7%, tungsten carbide: An internal combustion engine tappet member having a high joining strength, formed by liquid phase sintering a green compact having a composition consisting of the remainder. 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 which are Fe,
On the top surface on the cam contact surface side of the low alloy steel tappet body having a composition of unavoidable impurities, Co: 20 to 30%, Ni: 3 to 15%, (Co + Ni: 25 to 35%), P: 0.1-1%, one of carbides of Nb, V, Ti, Mo, and Ta
One or more kinds: 0.1 to 7%, tungsten carbide: An internal combustion engine tappet member having a high joining strength, formed by liquid phase sintering a green compact having a composition consisting of the remainder. 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
%, The balance being Fe and unavoidable impurities, the tip surface of the low alloy steel tappet body on the cam contact surface side as a tip material, Co: 20 to 30%, Ni: 3 to 15 % (However, Co + Ni: 25 to 35%), P: 0.1 to 1%, and one of carbides of Nb, V, Ti, Mo, and Ta
Species or two or more: 0.1 to 7%, Fe: 0.1 to 3%, Tungsten carbide: Remaining, compact powder compact is formed by liquid phase sintering, high bonding of chip material An internal combustion engine tappet member having strength. 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: 0.4-4.5%, Mo: 0.15-0.4%.
7%, one or two of which are Fe,
On the top surface on the cam contact surface side of the low alloy steel tappet body having a composition of unavoidable impurities, Co: 20 to 30%, Ni: 3 to 15%, (Co + Ni: 25 to 35%), P: 0.1-1%, one of carbides of Nb, V, Ti, Mo, and Ta
Species or two or more: 0.1 to 7%, Fe: 0.1 to 3%, Tungsten carbide: Remaining, compact powder compact is formed by liquid phase sintering, high bonding of chip material An internal combustion engine tappet member having strength.