JPS5852553B2 - Manufacturing method for iron-based sliding parts containing free graphite - Google Patents

Description

【発明の詳細な説明】 本発明は、焼結合金中に遊離黒鉛を分散せしめた鉄系摺
動部材を製造する方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an iron-based sliding member in which free graphite is dispersed in a sintered alloy.

固体潤滑剤として、すぐれた特性を有する黒鉛を鉄系焼
結合金の素地内に分散せしめる試みは古くから行なわれ
ているが、焼結温度が高い場合には、黒鉛は、鉄中に固
溶し、冷却後セメンタイトとなって析出して、硬くて脆
い材質となり、潤滑性は勿論被削性も著しく悪くなって
実用に供することができない。Attempts have been made for a long time to disperse graphite, which has excellent properties as a solid lubricant, into the matrix of iron-based sintered alloys, but when the sintering temperature is high, graphite dissolves into solid solution in the iron. However, after cooling, it precipitates as cementite, resulting in a hard and brittle material, and its lubricity and machinability are extremely poor, making it unsuitable for practical use.

このため（１） １０００℃以丁の比較的低い温度で焼
結することによりセメンタイトの析出を抑え、基地中に
遊離黒鉛を分散させる方法。For this reason, (1) a method of suppressing the precipitation of cementite and dispersing free graphite in the base by sintering at a relatively low temperature of 1000°C or less.

（乃黒鉛粉に予め銅メッキを施すことにより、鉄゛と黒
鉛粉とが直接接触することを防ぎ、基地中に遊離黒鉛を
分散させる方法などが提案されている。(A method has been proposed in which the graphite powder is plated with copper in advance to prevent direct contact between the iron and the graphite powder and to disperse free graphite in the base.

しかしこれらの方法は、それぞれに欠点を有する。However, each of these methods has its own drawbacks.

例えば（１）の場合には焼結温度が低いため強度が弱く
、耐摩耗性も充分でないこと、（２）の場合には比較的
有効な方法であるが、黒鉛粉に予め銅メッキを施す工程
を要しコスト高になること、および全ての黒鉛粉に均一
な厚さの銅メッキを施すのは困難であることなどの欠点
を有する。For example, in case (1), the sintering temperature is low, resulting in weak strength and insufficient wear resistance, and in case (2), although it is a relatively effective method, copper plating is applied to the graphite powder in advance. It has drawbacks such as requiring a process and increasing cost, and that it is difficult to plate all graphite powder with a uniform thickness of copper.

本発明は黒鉛が鉄中へ完全に固溶せず、一部遊離状態で
分散する高強度で１己潤滑性を有する鉄系摺動部材の製
造法を提供するものであって、鉄粉に重量比で１．５〜
５．０係のｃ、ｉ、ｏ〜５．０優のｐｂ、ｏ、３〜２．
０ ％のＳｎを添加混合し、所要の形状に成型した後、
１０５０℃〜１２００℃の温度で焼結することによって
得られる。The present invention provides a method for producing a high-strength, self-lubricating iron-based sliding member in which graphite is not completely dissolved in iron, but is partially dispersed in a free state. Weight ratio: 1.5~
5.0 c, i, o to 5.0 excellent pb, o, 3 to 2.
After adding and mixing 0% Sn and molding into the desired shape,
Obtained by sintering at a temperature of 1050°C to 1200°C.

（以下、俤は重量幅を示す。(Hereinafter, 忤 indicates the weight range.

）本発明中Ｃは一部は鉄中に固溶しセメンタイトとして
析出することにより、マトリックスの強化と耐摩耗性の
向上に寄与するとともに残余のＣは遊離黒鉛として基地
中に分散せしめられ潤滑性を発揮する。) In the present invention, a part of C is dissolved in iron and precipitated as cementite, thereby contributing to strengthening the matrix and improving wear resistance, and the remaining C is dispersed in the matrix as free graphite, which improves lubricity. demonstrate.

全炭素分として１．５％以下の場合には、遊離黒鉛の生
成が少なく固体潤滑作用の効果が小さく、又５． Ｏ％
以上の場合には、合金を脆化させるので範囲を１．５％
〜５．０ ％とする。When the total carbon content is 1.5% or less, the formation of free graphite is small and the solid lubricating effect is small; O%
In cases above, the range is 1.5% because it will make the alloy brittle.
~5.0%.

ｐｂは遊離黒鉛とともに潤滑機能を分担し、同時に材料
の被剛性改善に寄与するものであるが、この系において
ｐｂ添加の最も大きな効果はＳｎと共添加されることに
より焼結時におけるＦｅとＣとの反応を抑制して遊離黒
鉛を生成せしめることにある。PB shares the lubricating function with free graphite, and at the same time contributes to improving the stiffness of the material. However, in this system, the greatest effect of PB addition is that it is co-added with Sn, which reduces Fe and C during sintering. The purpose is to suppress the reaction with the carbon dioxide and generate free graphite.

ｐｂばＦｅと固溶度を有しない低融点金属で焼結中は溶
融状態にあるがｐｂとＦｅとの濡れ性は著しく悪いため
ｐｂのみ単独で添加しても遊離黒鉛を生成せしめる効果
は非常に小さい。Pb is a low melting point metal that does not have solid solubility with Fe and is in a molten state during sintering, but the wettability between Pb and Fe is extremely poor, so adding Pb alone has very little effect on generating free graphite. small.

一方Ｓｎ（／′ｉＦｅと固溶度を有する低融点金属であ
り、２係以下の添加ではＦｅ基地の強度を向上させる効
果を有するが、焼結中に合金化するため、Ｓｎのみを単
独で添加しても遊離黒鉛の生成に寄与しない。On the other hand, Sn (/'iFe) is a low melting point metal that has a solid solubility with Fe, and when added with a modulus of less than 2, it has the effect of improving the strength of the Fe base, but since it is alloyed during sintering, Sn alone is Even if added, it does not contribute to the formation of free graphite.

ｐｂとＳｎとを添加した本発明の場合にはＳｎの添加に
よってｐｂとＦｅとの濡れ性が著しく改善されることに
よって焼結中は溶融状態にあるｐｂがＦｅ表面を覆うよ
うになりＣとＦｅとの反応を抑制して遊離黒鉛を生成せ
しめる。In the case of the present invention in which Pb and Sn are added, the wettability between Pb and Fe is significantly improved by the addition of Sn, so that Pb in a molten state covers the Fe surface during sintering, and C and C. Free graphite is generated by suppressing the reaction with Fe.

この目的のためには１．５ ％〜５．０ ％のＰｂ、０
．３％〜２．０係のＳｎが必要であり、添加量が少ない
場合は、目的とする効果を達し得ない。For this purpose 1.5% to 5.0% Pb, 0
．． 3% to 2.0% Sn is required, and if the amount added is small, the desired effect cannot be achieved.

又ｐｂが５係以上の場合は、遊離黒鉛を生成せしめる目
的は達し得ても強度低下を生じ好ましくない、Ｓｎが２
多以上の場合には材質が脆くなり適当でない。In addition, if pb is 5 or more, the purpose of generating free graphite may be achieved, but the strength will decrease, which is undesirable.
If the amount is more than 1, the material becomes brittle and is not suitable.

なおＰｂ 、Ｓｎは上記組成範囲にあればＰｂ。Note that Pb and Sn are Pb if they are within the above composition range.

Ｓｎの金属粉あるいはＰｂ−’Ｓｎ合金粉を用いても同
様の効果を有する。Similar effects can be obtained by using Sn metal powder or Pb-'Sn alloy powder.

本発明の焼結温度は１０５０℃〜１２００℃の間で選択
されうる。The sintering temperature of the present invention can be selected between 1050<0>C and 1200<0>C.

焼結温度が１０５０℃以下では遊離黒鉛の生成では有利
な条件にあるが、強度が低く、耐摩耗性も充分でないた
め適当でない。A sintering temperature of 1050° C. or lower is advantageous for the production of free graphite, but is not suitable because the strength is low and the wear resistance is insufficient.

又１２００℃以上ではセメンタイトの析出量が多くなり
材質的に脆くなること、わよび寸法精度も劣ることなど
の理由により好１しくない。Further, temperatures higher than 1200°C are not preferable because the amount of cementite precipitated increases, the material becomes brittle, and the warpage and dimensional accuracy are poor.

以下実施例について述べる。Examples will be described below.

実施例 一１００メツシュのＦｅ粉、−２００メツシユのＰｂ粉
、Ｓｎ粉、Ｐｂ −Ｓｎ合金粉、表１に記載の天然黒鉛
粉をそれぞれ表１の組成に配合、混合し５ｔ／−の圧力
でプレス成型したのち、エンドサーミンクガス雰囲気中
で表１に記載した焼結温度で３０分焼結した。Example 1 100 mesh Fe powder, -200 mesh Pb powder, Sn powder, Pb-Sn alloy powder, and natural graphite powder listed in Table 1 were blended into the composition shown in Table 1 and mixed at a pressure of 5 t/-. After press molding, it was sintered for 30 minutes at the sintering temperature listed in Table 1 in an Endothermink gas atmosphere.

得られた焼結体の合金特性を表２に、耐摩耗性のテスト
結果を表３に示した。The alloy properties of the obtained sintered body are shown in Table 2, and the wear resistance test results are shown in Table 3.

以上の実施例で明らかなように、本発明は１０５０℃以
上の焼結温度においても黒鉛が鉄中に完全に固溶せず、
添加した黒鉛の一部を遊離黒鉛として分散せしめた高強
度で自己潤滑性を有する鉄系摺動部材を提供することが
できるものであって、本発明に用いる黒鉛粉末は−８０
メツシユ＋２００メツシユ粒度の比較的粗粒粉から一３
５０メツシュ（平均粒径８μ）粒度の微細粉ｌで適応可
能で、圧縮成型性、焼結後の寸法精度ならびに面粗度で
は微細粉を用いたものが優れ、機械的強度、耐摩耗性、
および焼結中のカーボンロス等は粗粒粉を用いたものが
優れていることが実施例からみても明らかで、用途に応
じて原料黒鉛粉の選択が可能である。As is clear from the above examples, the present invention is such that graphite does not completely dissolve in iron even at a sintering temperature of 1050°C or higher.
It is possible to provide an iron-based sliding member having high strength and self-lubricating properties in which a part of the added graphite is dispersed as free graphite, and the graphite powder used in the present invention is -80
Relatively coarse powder with a particle size of mesh + 200 mesh
It is possible to use fine powder with a particle size of 50 mesh (average particle size 8μ), and the use of fine powder is superior in terms of compression moldability, dimensional accuracy after sintering, and surface roughness, as well as mechanical strength, wear resistance,
It is clear from the examples that the use of coarse powder is superior in terms of carbon loss during sintering, and the raw material graphite powder can be selected depending on the application.

同本発明の実施に当っては重量係で、０．１〜３．５０
俤のＮｔ ｚ Ｏ−２〜０．８％のＰあるいは１〜５係
Ｃｕなどを添加して更に強度の向上を計る等の本発明の
目的を損なわない範囲で他の少量の添加物を含有せしめ
るとか、使用に当って更に潤滑油を含浸する等が可能な
ことは言う筐でもない。In implementing the present invention, the weight ratio is 0.1 to 3.50.
Contains small amounts of other additives within a range that does not impair the purpose of the present invention, such as adding 2 to 0.8% of P or 1 to 5 Cu to further improve the strength. There is no need to mention that it is possible to further impregnate the housing with lubricating oil during use.

Claims (1)

【特許請求の範囲】[Claims] １ 焼結合金のマ） ＩＪラックス中遊離黒鉛を分散せ
しめる方法であって、鉄粉中に重量幅で、１．５〜５．
０多のＣ，１，０〜５．０係のＰｂ 、 ０．３〜２．
０優のＳｎを含有せしめた粉末圧縮成型体を１０５０〜
１２００℃の温度で焼結することを特徴とする遊離黒鉛
含有鉄系摺動部材の製造法。1) A method of dispersing free graphite in IJ lux in a weight range of 1.5 to 5.5% by weight in iron powder.
C of 0, Pb of 1,0 to 5.0, 0.3 to 2.
Powder compression molded body containing 0% Sn is 1050 ~
A method for producing an iron-based sliding member containing free graphite, characterized by sintering at a temperature of 1200°C.