JPS60200950A - Floating seal - Google Patents

Abstract

PURPOSE:To provide a floating seal which is improved in the wear resistance of the sealing surface and the strength, machineability and castability of the base metal by incorporating a specific amt. of C, Si, Mn, Cu, Ni, etc. into Fe and forming the sealing surface into the remelted chill structure. CONSTITUTION:A floating seal is cast of an alloy consisting of 2.5-3.8wt% C, 2.0-4.0% Si, 0.4-2.0% Mn, 0.5-4.0% Cu, <=4.0% Ni, 0.3-1.3% >=1 kinds among Cr, Ti, W and V and, if necessary, 0.3-1.5% Mo, <=0.5% P, <=0.2% S and the balance Fe and unavoidable impurities. The sealing surface is remelted and cooled by using a heat source of high-energy density heat source to form a chill structure. The base metal of such floating seal has substantial machineability in as-case state and the sealing surface has excellent wear resistance. Since low- alloy cast iron is used, the cost is low.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a floating seal used as a shaft cover for construction machinery and construction vehicles, and particularly to a cast iron floating seal.

The floating seal is arranged at the end of the rotating shaft 1 as shown in Fig. 1, and is connected to the casing 2 and rotating cover 3 through O-rings 5. The seals 4.4 are connected to the casing 2 and the rotating cover 3, respectively, and rotate and slide on the sealing surfaces 6.6.
Sediment, dust, and sewage that enter between the gaps are sealed by the O-ring 5.5 and the sealing surface 6.6 of the floating seal, and the sealing surface 6.6 has special sealing properties depending on the sliding conditions. That is, wear resistance and corrosion resistance are required.

In addition, the floating seal forms a contact surface with the O-ring on the outer circumferential side, and in order to maintain the sealing properties of the O-ring, surface precision of this surface is also required.

Such a 70-ring seal mainly has a sealing surface with an I resistance of
With an emphasis on wear resistance, we use wear-resistant cast iron, such as white cast iron,
r-M(+alloy cast iron is used.These alloy cast υ,
Mainly contains a large amount of high-hardness Cr carbide to obtain a wear-resistant effect, and furthermore, it has excellent base strength and hardness because it is converted to martenzai 1 or more in the as-cast state.

However, although such wear-resistant base metal cast iron has excellent wear-resistant effects by being quenched, it is extremely IZI.
However, there are problems such as poor machinability due to poor OI, poor VJ machinability due to the addition of elements between the rows, and high cost due to the inclusion of many heat treatment steps.

To solve this problem, it is possible to chill only the sealing surface of the floating seal with a cold metal and form a chilled layer with excellent surface abrasion resistance only in the necessary parts, but it is possible to Not only is the structure not fully stabilized, but the surface hardness and hardness are insufficient, making it impractical.

On the other hand, in recent years, chilling by remelting and cooling has been attracting attention as a means of chilling the surface of small castings. By remelting the surface of the material that is difficult to damage by electron beam irradiation and rapidly cooling it due to the heat capacity of the base material itself, a chilled structure with excellent wear resistance can be formed.

A 70-ding seal provided with a chill layer by remelting and cooling is disclosed in Japanese Patent Application No. 56-5, which was previously proposed by the present applicant.
No. 6908, but the purpose of the present invention is to further improve this floating seal having a chilled structure by cooling the remelted metal 11, and to improve the whiteness of the sealing surface as a floating seal.
The object is to provide a material with excellent wear resistance, base material strength, machinability, and castability.

What is the feature of this invention? As stated in the claims, cast iron 7 is composed of the following two constituent elements.
It is on the 0-ting seal.

1) Chemical components in weight%: C: 2.5-3.8%, s
r: 2.0-4.0%, Mn: 0.4-2°0%,
Cu: Q, 5-4.0%, Ni: 4.0% or less, Cr
, Ti, W, V, one or more types of 2 and 0.3 to 1
．． 3%, or roughly 20.3% to 1.5% MO, with the remainder being unavoidable impurities.

2) The sealing surface must have a remelted chill structure.

The floating seal of the present invention, which has the above-mentioned features, has a fine chill structure unique to re-melted cold rubber on the sealing surface, and the white body of the 1U material has excellent machinability and castability. It is.

The reasons for limiting the ingredients are described below.

C controls the del organization's letan tie 1~乎 and ff
If it is less than 2.5%, the amount of kementite m in the chilled structure will be insufficient, resulting in insufficient wear resistance and rough machinability.

On the other hand, if it exceeds 3.8%, the rementite in the chilled structure becomes coarse and blowholes due to the re-molten metal 11 are likely to occur in the chilled structure, and the amount of parent graphite becomes excessive, resulting in a decrease in strength. Selected in %.

Although Si is related to Cm, it contributes to the graphitization of cast iron, and if it is less than 2.0%, the graphitization of the base material will not proceed and the base material itself will become chilled, resulting in a significant decrease in machinability. If it exceeds 0%, graphitization progresses excessively and the strength of the base material decreases, and blowholes are likely to occur during remelting and chilling.
Selected at 0%.

Mn is effective in removing S, which is a harmful element, and has a tendency to chill, so it suppresses the growth of graphite caused by CuXNi, which is the graphitization source thread, and contributes to improving the base strength.
If it exceeds 2.0%, the tendency to chill becomes noticeable, leading to a decrease in toughness and machinability. Also, if it is less than 0.4%, S removal,
0.4 because no effect on improving base strength can be obtained.
~2.0%.

Cu reduces the wall thickness sensitivity of hook iron and improves the strength and corrosion resistance of the base metal, but if it exceeds 4.0%, it will not be completely dissolved in the matrix and will precipitate, resulting in a decrease in the cutting mechanical properties of IIl+J. invite. On the other hand, if it is less than 0.5%, the above effects cannot be obtained. Therefore, it is redundant (0.5 to 4.0%).

Like Cu, Ni reduces the wall thickness sensitivity of cast iron.I! It is effective in improving base strength. In addition, in the case of thin-walled pits, the addition of Cu alone tends to cause whitening due to the effects of Or, MO, etc., but the addition of Ni, which has a greater graphitization tendency than Qu, can suppress whitening. . but,
If it exceeds 4.0%, it will increase the residual ausbunite in the base and reduce the strength.
．． Selected below 0%.

By selectively adding one or more of Cr, Ti, W, and V, a highly hard carbide is formed to improve wear resistance! However, if it is less than 0.3%, the effect of improving hardness cannot be obtained, and if it exceeds 1.3%, the as-cast hardness of ffJ becomes too high and the machinability is impaired. 3～
Select at 1.3%. As the element that improves wear resistance, it is most preferable to select Or, which forms fine carbides and also has a grainy effect to improve base strength.

Furthermore, base strength can be increased by adding MO.
It is preferable that the base of the re-melted chilled structure be converted into martenzyme, but if it is less than 0.3%, it will not be effective.
If it exceeds 1.5%, the base metal will become martensite or bainite, resulting in poor machinability (0.3 to 1.5%).
Select by %.

1), which are unavoidable impurities, S is 0.5% or more F, 0.
It is desirable to suppress it to 2% or less.

The floating seal of the present invention having the chemical components as explained above is cast and then the sealing surface is remelted and cooled.
A chill coarse weave 61 is thus formed. Such a remelting means uses a high-density energy heat source of 10 w/ci to 10 w/cm, specifically an electron beam, a laser beam, a TIG arc, or a plasma arc. However, 10W/cf
At a high-density single energy exceeding fl, the surface evaporates before the sealing surface is remelted and undergoes impact hardening, but sufficient remelting a1! layer cannot be obtained, and relatively less than 10 W/cffl. With low-density energy heating, the rate of remelting α11 and cooling is slow, and not only does the thermal effect on the base material be significant, but the chilled structure also becomes spherical, making it impossible to obtain sufficient hardness and strong electric power. .

As described above, the floating seal of the present invention has a base material made of cast iron with good machinability and a Rockwell hardness of about 20 to 35 in the as-cast state, and the seal surface is made of remelted cast iron with excellent wear resistance. It is an a-ding seal that has a cooling chill layer and is low in material cost as it is made of low alloy cast iron.

Furthermore, the method of forming a UE dowel according to the present invention can also be applied to a general 4R seal ring which is used for sliding on the seal surface of a floating seal for optical use.

[Brief explanation of drawings]

Drawing [31 Present Invention Fling L] - It is a sectional view showing the state of use of the tinting seal. 1... Rotating shaft, 4... Futing seal, 5
... O-ring, 6... Seal surface, 61... Chill l
fA. Qrl rr Applicant Nippon Piston Ring Co., Ltd.

Claims (2)

[Claims] (1) In the H&7i floating seal,
Chemical components in weight%: C: 2.5-3.8%, Si:
2.0-4.0%, Mn: 0.4-2.0%, C1:0
．． 5 to 4.0%, Ni: i0% or less, Cr, Ti, W,
1. A floating seal comprising 0.3 to 1.3% of one or more of V, the remainder being unavoidable impurities and Fc, and having a sealing surface having a remelted and chilled structure. (2) The chemical composition of the floating seal is 51% by weight.
"U, C: 2.5-3.8%, Si: 2.0-4.0
%, Mn: 0.4-2.0%, CLI: 0°5-4,
0%, Ni: 41.0% or less, Mo: 0°3 to 1.5%
, Or, Ti, W, V, one or more types 0.3
The floating seal according to claim 1, characterized in that it consists of ~1.3%, P: 0.5% or less, S: 0.2% or less, and the balance is Fe.