JPH09302411A - Production of non-decarburized and wear resistant spheroidal graphite cast iron casting parts - Google Patents
Production of non-decarburized and wear resistant spheroidal graphite cast iron casting partsInfo
- Publication number
- JPH09302411A JPH09302411A JP11990596A JP11990596A JPH09302411A JP H09302411 A JPH09302411 A JP H09302411A JP 11990596 A JP11990596 A JP 11990596A JP 11990596 A JP11990596 A JP 11990596A JP H09302411 A JPH09302411 A JP H09302411A
- Authority
- JP
- Japan
- Prior art keywords
- cast iron
- spheroidal graphite
- graphite cast
- heat treatment
- iron casting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- Heat Treatment Of Articles (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、表層部に脱炭層の
生成がなく、かつ耐摩耗性を有する球状黒鉛鋳鉄鋳物部
品の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a spheroidal graphite cast iron casting part which has no decarburized layer on the surface layer and has wear resistance.
【０００２】[0002]
【従来の技術】鋼や鋳鉄製の部材や部品は、その用途目
的に応じて、種々の温度で熱処理を施される場合が多
い。例えば、工具鋼の焼入や耐熱鋼の溶体化その他拡散
を目的とした熱処理のための加熱は、１２００〜１３０
０℃もの高温度となる。この場合、化学組成の変化があ
ってはならないので、高温度の加熱の際には鋼表面で酸
化、脱炭等が起こらぬようにせねばならない。そのため
には、なるべく熱処理部品を大気中で高温度に加熱する
ことは避けた方がよいとされている。例えば、光沢ある
鋼の表面の酸化、脱炭を防止しながら行なう熱処理は、
総称して光輝熱処理として知られている。光輝熱処理
は、適当な還元性または中性雰囲気炉もしくは真空炉中
で加熱、冷却することによって行なわれている。2. Description of the Related Art Members and parts made of steel or cast iron are often heat-treated at various temperatures according to the purpose of use. For example, heating for quenching of tool steel, heat treatment of heat-resistant steel, or other heat treatment for diffusion is performed from 1200 to 130.
The temperature is as high as 0 ° C. In this case, since the chemical composition should not change, it is necessary to prevent oxidation and decarburization on the steel surface during heating at high temperature. To that end, it is said that it is better to avoid heating the heat-treated component to a high temperature in the atmosphere as much as possible. For example, the heat treatment performed while preventing the oxidation and decarburization of the surface of shiny steel,
Collectively known as bright heat treatment. The bright heat treatment is carried out by heating and cooling in a suitable reducing or neutral atmosphere furnace or vacuum furnace.
【０００３】また、加熱雰囲気の例としては、メタン
（ＣＨ4 ）、エタン（Ｃ2Ｈ6 ）、プロパン（Ｃ3Ｈ8 ）
等に空気を混合し、Ｎｉ触媒を用いて分解し、生じたＨ
2Ｏを除去したＣＯ約２０％、Ｈ2約４０％、Ｎ2約４０
％の組成の吸熱型ガス（エンドガスまたはＲＸガスとよ
ばれる。）中で処理品を加熱する。このガスにＣＨ4な
どを添加することがあり、これはエンリッチガスとよば
れる。更に、一種またはそれ以上の塩類を溶かしてお
き、その中に熱処理部品を浸漬する塩浴も用いられる。
熱処理温度や滲炭、窒化等の表面硬化を行なうか否かで
塩の種類が選定される。例えば、鋼の焼戻し等の２００
〜５００℃の低温度のところは硝酸塩や亜硝酸塩を単独
または混合物として用いられる。また、５００〜１００
０℃の中温度用塩浴には、ＮａＣｌ（融点：８０３
℃）、ＣａＣｌ2 （融点：７７０℃）、Ｎａ2 ＣＯ
3 （融点：８５６℃）の混合塩が通常用いられる。Further, examples of the heating atmosphere include methane (CH 4 ), ethane (C 2 H 6 ), propane (C 3 H 8 ).
H mixed with air and decomposed using Ni catalyst
2 O removed CO about 20%, H 2 about 40%, N 2 about 40
The processed product is heated in an endothermic gas (called end gas or RX gas) having a composition of 10%. CH 4 or the like may be added to this gas, which is called an enriched gas. Further, a salt bath in which one or more salts are dissolved and the heat-treated component is immersed therein is also used.
The type of salt is selected depending on the heat treatment temperature and whether or not surface hardening such as carburizing and nitriding is performed. For example, 200 for tempering steel, etc.
Nitrate or nitrite is used alone or as a mixture at a low temperature of up to 500 ° C. Also, 500 to 100
NaCl (melting point: 803
℃), CaCl 2 (melting point: 770 ℃), Na 2 CO
A mixed salt of 3 (melting point: 856 ° C.) is usually used.
【０００４】鋳鉄の鋳造品や部材に通常の熱処理を施し
た場合、その表層部には脱炭層（フェライト層）が生成
するので、この脱炭層（フェライト層）を機械加工によ
り通常除去せざるをえない。特開昭５５−１５８２４９
号公報においては、「Ｃ：３．３〜３．６％、Ｓｉ：
１．６〜２．１％、Ｍｎ：０．５〜１．０％、残留Ｍ
ｇ：０．０３〜０．０６％、Ｃｕ：０．８〜１．２％、
Ｃｒ：０．１〜０．６％、残部Ｆｅよりなり、鋳物表面
における脱炭層（フェライト層）の生成を防止した鋳放
しパーライト球状黒鉛鋳鉄鋳物。」を提案している。[0004] When a cast iron cast product or member is subjected to normal heat treatment, a decarburized layer (ferrite layer) is formed on the surface layer portion thereof, and therefore this decarburized layer (ferrite layer) usually has to be removed by machining. I can't. JP-A-55-158249
In the publication, "C: 3.3 to 3.6%, Si:
1.6-2.1%, Mn: 0.5-1.0%, residual M
g: 0.03 to 0.06%, Cu: 0.8 to 1.2%,
An as-cast pearlite spheroidal graphite cast iron casting composed of Cr: 0.1 to 0.6% and the balance Fe, and preventing the formation of a decarburized layer (ferrite layer) on the surface of the casting. "Has been proposed.
【０００５】上記特開昭５５−１５８２４９号公報にお
ける提案は、パーライト系球状黒鉛鋳鉄は、鋳放しで安
定して８０％以上のパーライト化率を有することが難し
いため、通常は鋳造後９００℃前後に加熱、続いて空冷
するいわゆる焼ならし熱処理によって製作されている。
この場合、鋳物表面に脱炭層（フェライト層）が生成さ
れる。鋳物表面にフェライト層が生成された場合、パー
ライト地に比べて機械的性質、疲労強度が低下し、更に
構造用部品などの表面に亀裂が発生して疲労破壊の原因
となる等の課題があった。The proposal in the above-mentioned Japanese Patent Laid-Open No. 55-158249 is such that it is difficult for pearlitic spheroidal graphite cast iron to have a stable pearlite conversion rate of 80% or more in the as-cast condition. It is manufactured by so-called normalizing heat treatment in which the material is heated to the air and then air-cooled.
In this case, a decarburized layer (ferrite layer) is formed on the surface of the casting. When a ferrite layer is formed on the surface of the casting, mechanical properties and fatigue strength are lower than those of pearlite material, and there are problems such as cracking on the surface of structural parts, which causes fatigue fracture. It was
【０００６】そこで、この提案においては、化学組成特
にＣｒ量を０．１〜０．６％と数値限定することによ
り、鋳物表面に脱炭層（フェライト層）の生成を防止す
るとするもので、熱処理炉の加熱雰囲気等を含めた熱処
理条件については何等記載なく、また示唆もされていな
い。Therefore, in this proposal, the formation of a decarburized layer (ferrite layer) on the surface of the casting is prevented by limiting the chemical composition, particularly the amount of Cr to 0.1 to 0.6%. There is no description or suggestion of any heat treatment conditions including the heating atmosphere of the furnace.
【０００７】また、特開昭５６−９３５４号公報におい
ては、「Ｃ３．１〜４．１％、Ｓｉ２．１〜３．５％、
Ｍｎ１％以下、Ｐ０．１５％以下、Ｓ０．０３％以下、
Ｃｕ１．５％以下、Ｎｉ２．５％以下、黒鉛球状化処理
元素Ｍｇ、Ｃａ、Ｃｅ、Ｙのうちの１つまたは２つ以上
を０．１％以下含有し、基地組織がフェライト２０〜７
０％の混在する針状微細組織である耐摩耗部品用強靱球
状黒鉛鋳鉄。」を開示している。このような組織を得る
方法として、通常の化学組成の、或いはＮｉ、Ｃｕ、Ｍ
ｏ等を含有する球状黒鉛鋳鉄を鋳造のままで或いは熱処
理によって予めマルテンサイト組織の基地とし、次に急
熱してＡ1変態域まで温度を上げて保持したのち、空冷
または水冷の急冷または急冷・焼戻によっている。上述
の如く、この提案は、鋳造のままで或いは熱処理によっ
て予めマルテンサイト組織の基地とし、次に所定の熱処
理を施すことにより針状微細組織を有する耐摩耗部品用
強靱球状黒鉛鋳鉄を得るものである。Further, in JP-A-56-9354, "C3.1-4.1%, Si2.1-3.5%,
Mn 1% or less, P 0.15% or less, S 0.03% or less,
Cu 1.5% or less, Ni 2.5% or less, and 0.1% or less of one or more of the graphite spheroidizing elements Mg, Ca, Ce and Y, and the matrix structure is ferrite 20 to 7.
A tough spheroidal graphite cast iron for wear resistant parts with a needle-like microstructure of 0% mixed. Is disclosed. As a method of obtaining such a texture, Ni, Cu, M of ordinary chemical composition,
As-cast spheroidal graphite cast iron containing o or the like is formed as a base of a martensite structure in advance by as-casting or by heat treatment, and then rapidly heated to raise the temperature to the A 1 transformation region and held, and then air-cooled or water-cooled or rapidly cooled. It is tempered. As described above, this proposal is to obtain a tough spheroidal graphite cast iron for wear-resistant parts having a needle-shaped microstructure by forming a base of martensite structure in the as-cast state or by heat treatment in advance and then subjecting it to a predetermined heat treatment. is there.
【０００８】また、特開昭６４−５６８１９号公報に開
示の「高耐摩耗ダクタイル鋳鉄の製造方法」は、Ｃ：
３．０〜４．０ｗｔ％、Ｓｉ：２．０〜３．５ｗｔ％、
Ｍｎ：０．１〜０．９ｗｔ％、Ｃｕ：２．０ｗｔ％以
下、Ｎｉ：２．０ｗｔ％以下、を基本合金成分とし、さ
らにＭｏ：０．２〜２．０ｗｔ％、Ｃｒ：０．２〜２．
０ｗｔ％、Ｖ：０．２〜２．０ｗｔ％、Ｗ：０．２〜
２．０ｗｔ％のうち１種またはそれ以上を含有させ、残
部が実質的にＦｅ及び微量不純物からなり、基地組織に
炭化物を分散析出させたダクタイル鋳鉄を、８２０〜９
５０°Ｃに０．５〜５時間保持した後、直ちに２２０〜
４００°Ｃに急冷し、その温度で０．５時間以上保持す
るオーステンパー処理を施すもので、基地組織を高硬度
の炭化物と高強度、高靱性のベーナイトとの複合組織と
することにより従来のオーステンパー処理したダクタイ
ル鋳鉄に比較して耐摩耗性を著しく向上させ、合金工具
鋼等の特殊鋼に匹敵する高耐摩耗性を有し、さらに衝撃
値も同等あるいはそれ以上であり、冷間プレス用パン
チ、ダイス等の他、各種摺動部品に使用できる高耐摩耗
性ダクタイル鋳鉄の製造方法を提供せんとするものであ
る。[0008] Further, "Production Method of Highly Abrasion Resistant Ductile Cast Iron" disclosed in Japanese Patent Laid-Open No. 64-56819, C:
3.0-4.0 wt%, Si: 2.0-3.5 wt%,
Mn: 0.1 to 0.9 wt%, Cu: 2.0 wt% or less, Ni: 2.0 wt% or less as a basic alloy component, and Mo: 0.2 to 2.0 wt%, Cr: 0.2 ~ 2.
0 wt%, V: 0.2-2.0 wt%, W: 0.2-
820 to 90% of ductile cast iron containing 2.0 or more of 2.0 wt% and the balance consisting essentially of Fe and trace impurities, in which carbide is dispersed and precipitated in the matrix structure.
After holding at 50 ° C for 0.5 to 5 hours, immediately 220 to
It is rapidly cooled to 400 ° C and austempered for holding at that temperature for 0.5 hours or more. By forming the matrix structure into a composite structure of high hardness carbide and high strength and high toughness bainite, Compared to austempered ductile cast iron, it has significantly improved wear resistance, has high wear resistance comparable to special steel such as alloy tool steel, and has an impact value equal to or higher than that of cold press. It is intended to provide a method for producing highly wear-resistant ductile cast iron that can be used for various sliding parts in addition to punches, dies, and the like.
【０００９】また、特公平４−６１０４７号公報に開示
の「強靱性を有する球状黒鉛鋳鉄部品の製造方法」は、
Ｃ：３．０〜４．０重量％、Ｓｉ：２．０〜４．０重量
％、Ｍｇ：０．０２〜０．１重量％と、Ｍｎ：０．５〜
２．０重量％と、Ｎｉ：０．５〜３．０重量％またはＣ
ｕ：０．３〜２．０重量％の少なくとも一方とを有し、
かつ残部が実質的にＦｅとされた組成の球状黒鉛鋳鉄
を、８３０〜１０００°Ｃに５時間以内加熱保持したの
ち１７０〜２１０°Ｃに急冷し、しかる後２２０〜４２
０°Ｃに５分間以上加熱保持するオーステンパー処理を
施すもので、表面にマルテンサイト組織を生成させるこ
となく均一なベーナイト組織を生成して、強靱性の球状
黒鉛鋳鉄部品を得ることを目的とし、得られた球状黒鉛
鋳鉄部品は、例えばステアリングナックルやコンロッド
等の自動車用部品等の強度部品として用いられる、とす
るものである。Further, the "method for manufacturing a spheroidal graphite cast iron part having toughness" disclosed in Japanese Patent Publication No. 4-61047,
C: 3.0-4.0 wt%, Si: 2.0-4.0 wt%, Mg: 0.02-0.1 wt%, Mn: 0.5-
2.0 wt% and Ni: 0.5 to 3.0 wt% or C
u: at least one of 0.3 to 2.0% by weight,
And, the spheroidal graphite cast iron having a composition in which the balance is substantially Fe is heated and held at 830 to 1000 ° C for 5 hours and then rapidly cooled to 170 to 210 ° C, and then 220 to 42 ° C.
Austempering is performed by heating and holding at 0 ° C for 5 minutes or more. The purpose is to obtain a toughened spheroidal graphite cast iron part by forming a uniform bainite structure without forming a martensite structure on the surface. The obtained spheroidal graphite cast iron part is used as a strength part for automobile parts such as steering knuckle and connecting rod.
【００１０】以上述べたように、各種各様の提案がなさ
れているが、後述する本発明のように、鋳物部品の表層
部が無脱炭（フェライト層が存在しない状態）で、かつ
該鋳物部品の表層部から内部まで均一なベーナイト組織
を有する耐摩耗性球状黒鉛鋳鉄鋳物部品に関するもので
はない。As described above, various kinds of proposals have been made, but as in the present invention described later, the surface layer portion of a casting part is non-decarburized (state in which the ferrite layer does not exist) and the casting is It does not relate to a wear-resistant spheroidal graphite cast iron casting part having a uniform bainite structure from the surface layer to the inside of the part.
【００１１】[0011]
【発明が解決しようとする課題】自動車用ギヤーケース
等には耐摩耗性を付与するために、浸炭処理や窒化（軟
窒化）された鍛造品が使用されているが、鍛造品は鋳
造品よりコスト高である。鍛造品では振動音を軽減で
きないので、騒音上課題を有する。一方、鋳鉄鋳造品
は鍛造品に比べて安価に製造できること。鋳鉄では振
動のエネルギーが組織中の黒鉛に吸収されるため減衰能
が高く、部材相互のかみあい音、振動音を軽減できる等
の利点がある。従来部品の製作は、まず鋳物品を粗加工
した後、オーステンパー処理を施し、次いで仕上げ加工
を行っていた。該オーステンパー処理は大気雰囲気を有
する熱処理炉中で加熱後、ソルトバス中に浸漬して恒温
変態処理が施されていた。このため、鋳物品の表層部に
硬度が低く、耐摩耗性に劣る脱炭層（フェライト層）が
生成し、オーステンパー処理後に、機械加工により脱炭
層（フェライト層）の削除を余儀なくされていた。な
お、鋳物品の表層部の脱炭を防止または軽減するため
に、鋳物品の表面に前もって脱炭防止剤を塗布した後、
大気雰囲気を有する熱処理炉中で加熱したとしても、熱
処理後に脱炭防止剤の除去工程を必要とする課題もあっ
た。Carburized or nitrided (soft-nitrided) forged products are used in automobile gear cases and the like in order to impart wear resistance. However, forged products are better than cast products. The cost is high. Since forged products cannot reduce vibration noise, there is a noise problem. On the other hand, cast iron cast products can be manufactured at a lower cost than forged products. In cast iron, since vibration energy is absorbed by graphite in the tissue, it has a high damping ability, and has advantages such as reduction of meshing noise between members and vibration noise. Conventionally, in the production of parts, a cast article is first roughly processed, then austempered, and then finished. The austempering treatment was carried out by heating in a heat treatment furnace having an air atmosphere and then immersing in a salt bath to carry out a constant temperature transformation treatment. For this reason, a decarburized layer (ferrite layer) having low hardness and poor wear resistance is formed on the surface layer portion of the cast article, and after the austempering treatment, the decarburized layer (ferrite layer) must be removed by machining. Incidentally, in order to prevent or reduce decarburization of the surface layer portion of the cast article, after applying a decarburization inhibitor to the surface of the cast article in advance,
Even if it is heated in a heat treatment furnace having an air atmosphere, there is also a problem that a step of removing the decarburization inhibitor is required after the heat treatment.
【００１２】本発明者等は、鋳物品の表層部に生成する
数１０ミクロン厚さの脱炭層が大気雰囲気を有する熱処
理炉内での鋳物品の加熱中に生ずることをつきとめ、鋳
物品を真空中で加熱処理すれば、表層部での脱炭層の生
成を未然に防止することができること、そして該鋳物品
の表層部にパーライト組織を生じさせない冷却速度でソ
ルトバス中に浸漬して、ベーナイト変態させることによ
り該鋳物品の表層部から内部まで均一なベーナイト組織
を確保できることに想到し、本発明をなした。本発明の
目的は、球状黒鉛鋳鉄鋳物部品を予め所定寸法に加工し
た後、該鋳物部品を真空雰囲気を有する熱処理炉内で、
あるいはＲＸガス雰囲気を有する熱処理炉内で保持均熱
してオーステナイト化処理を施し、しかる後に該鋳物部
品の表層部にパーライト組織を生じさせない冷却速度
で、該熱処理炉に近接して配置したソルトバス中に浸漬
し、恒温変態を施すことにより該鋳物部品の表層部から
内部まで均一なベーナイト組織を確保できる無脱炭・耐
摩耗性球状黒鉛鋳鉄鋳物部品の製造方法を提供すること
にある。なお、本発明における「表層部」とは、球状黒
鉛鋳鉄鋳物部品の表面を含み約２０〜３０μｍ深部まで
の領域を意味する。The inventors of the present invention have found out that a decarburized layer having a thickness of several tens of microns formed on the surface layer portion of a cast article occurs during heating of the cast article in a heat treatment furnace having an air atmosphere, and the cast article is vacuumed. It is possible to prevent the formation of a decarburized layer at the surface layer by heat treatment in advance, and to immerse in a salt bath at a cooling rate that does not cause a pearlite structure in the surface layer of the cast article to transform the bainite transformation. The present invention was made based on the idea that a uniform bainite structure can be secured from the surface layer portion to the inside of the cast article by doing so. An object of the present invention is to process a spheroidal graphite cast iron casting part in a predetermined size in advance, and then heat the casting part in a heat treatment furnace having a vacuum atmosphere,
Alternatively, in a salt bath placed close to the heat treatment furnace at a cooling rate that does not generate a pearlite structure in the surface layer portion of the casting part after holding and soaking in a heat treatment furnace having an RX gas atmosphere to perform austenitizing treatment. It is an object of the present invention to provide a method for producing a non-decarburizing / abrasion resistant spheroidal graphite cast iron casting part capable of ensuring a uniform bainite structure from the surface layer part to the inside of the casting part by immersing in the steel and subjecting it to a constant temperature transformation. The “surface layer portion” in the present invention means a region including the surface of the spheroidal graphite cast iron casting part to a depth of about 20 to 30 μm.
【００１３】[0013]
【課題を解決するための手段】本発明の無脱炭・耐摩耗
性球状黒鉛鋳鉄鋳物部品の製造方法は、真空雰囲気を有
する熱処理炉内で、球状黒鉛鋳鉄鋳物部品を８００〜９
５０°Ｃのオーステナイト温度領域に０．５〜３時間保
持均熱した後、前記熱処理炉から取り出し、パーライト
組織を生じない冷却速度でソルトバス中に浸漬し、続い
て該ソルトバス中で恒温変態処理を施し、その後放冷す
ることを特徴とする。本発明においては、真空雰囲気を
有する熱処理炉内の真空度が１０-1ｔｏｒｒ以上、最も
好ましくは２×１０-2ｔｏｒｒ以上、であることを特徴
とする。また、本発明においては、球状黒鉛鋳鉄鋳物部
品が予め所定寸法に機械加工されている。また、本発明
における、パーライト組織を生じない冷却速度を達成す
る手段としては、真空雰囲気を有する熱処理炉の扉を開
いて、球状黒鉛鋳鉄鋳物部品を取り出してからソルトバ
ス中に浸漬するまでの時間を５５秒以内、最も好ましく
は４５秒以内、とすることを特徴とする。そして、恒温
変態処理を、２５０〜４００°Ｃに溶融したソルトバス
中で所定時間浸漬して行う。この製造方法により、球状
黒鉛鋳鉄鋳物部品の表層部は無脱炭で、かつ該表層部か
ら内部に至るまで均一なベーナイト組織を確保すること
ができる。The method for producing a decarburization-free and wear-resistant spheroidal graphite cast iron casting part of the present invention is a method for manufacturing a spheroidal graphite cast iron casting part in a heat treatment furnace having a vacuum atmosphere at 800-9.
After holding and soaking in the austenite temperature region of 50 ° C. for 0.5 to 3 hours, the sample is taken out from the heat treatment furnace, immersed in a salt bath at a cooling rate that does not produce a pearlite structure, and then subjected to isothermal transformation in the salt bath. It is characterized in that it is subjected to a treatment and then allowed to cool. The present invention is characterized in that the degree of vacuum in the heat treatment furnace having a vacuum atmosphere is 10 −1 torr or more, and most preferably 2 × 10 −2 torr or more. Further, in the present invention, the spheroidal graphite cast iron casting part is machined to a predetermined size in advance. Further, in the present invention, as a means for achieving a cooling rate that does not generate a pearlite structure, the door of a heat treatment furnace having a vacuum atmosphere is opened, and the time from taking out the spheroidal graphite cast iron casting part to immersing it in a salt bath is shown. Is within 55 seconds, and most preferably within 45 seconds. Then, the isothermal transformation process is carried out by immersing in a salt bath melted at 250 to 400 ° C. for a predetermined time. By this manufacturing method, the surface layer portion of the spheroidal graphite cast iron casting component can be decarburized and a uniform bainite structure can be secured from the surface layer portion to the inside.
【００１４】次に、本発明における他の製造方法は、Ｒ
Ｘガス雰囲気を有する熱処理炉内で、球状黒鉛鋳鉄鋳物
部品を８００〜９５０°Ｃのオーステナイト温度領域に
０．５〜３時間保持均熱した後、前記熱処理炉から取り
出し、パーライト組織を生じない冷却速度でソルトバス
中に浸漬し、続いて該ソルトバス中で恒温変態処理を施
し、その後放冷することを特徴とする。球状黒鉛鋳鉄鋳
物部品が、予め所定寸法に機械加工されていること、パ
ーライト組織を生じない冷却速度を達成する手段、およ
び恒温変態処理の条件については、前述の真空雰囲気を
有する熱処理炉を用いて行う製造方法の場合と同様であ
る。Next, another manufacturing method according to the present invention is
In a heat treatment furnace having an X gas atmosphere, a spheroidal graphite cast iron casting part is held and soaked in the austenite temperature range of 800 to 950 ° C for 0.5 to 3 hours, then taken out from the heat treatment furnace and cooled without forming a pearlite structure. It is characterized in that it is immersed in a salt bath at a speed, then subjected to a constant temperature transformation treatment in the salt bath, and then allowed to cool. Spheroidal graphite cast iron cast parts are machined to a predetermined size in advance, means for achieving a cooling rate that does not generate a pearlite structure, and conditions for the isothermal transformation treatment, using a heat treatment furnace having a vacuum atmosphere described above. This is similar to the case of the manufacturing method performed.
【００１５】オーステナイト化温度については、８００
°Ｃ未満の温度では均一なオーステナイトが得られず、
９５０°Ｃを越える温度ではオーステナイト結晶粒の粗
大化を招くので、８００〜９５０°Ｃに設定する。次
に、球状黒鉛鋳鉄鋳物部品の表層部にパーライト組織を
生じないようにする手段として、熱処理炉の扉を開い
て、該鋳物部品を取り出し、ソルトバスに浸漬するまで
の時間を５５秒以内、最も好ましくは４５秒以内、とす
るのは、これ以上の時間を要した場合には連続冷却曲線
（ＣＣＴ曲線）におけるパーライトノーズにかかるか、
またはパーライト生成開始線と交差する冷却となり、該
鋳物部品の表層部にパーライト組織が生成することにな
るため、パーライトノーズを避けた冷却速度を確保する
ためである。このために、５５秒以内、最も好ましくは
４５秒以内、にソルトバス中に浸漬する。また、恒温変
態処理のためのソルトバス温度については、２５０°Ｃ
未満の温度ではマルテンサイト変態を伴い靱性が低下
し、４００°Ｃを越える温度では均一なベーナイト基地
が得られないため、２５０〜４００°Ｃに溶融ソルトバ
スの温度を設定する。なお、恒温変態処理での保持時間
については、熱処理する部材の大きさによって適宜設定
する必要があるが、大略０．５〜３時間である。The austenitizing temperature is 800
At temperatures below ° C, uniform austenite cannot be obtained,
A temperature exceeding 950 ° C causes coarsening of austenite crystal grains, so the temperature is set to 800 to 950 ° C. Next, as a means for preventing the formation of a pearlite structure in the surface layer portion of the spheroidal graphite cast iron cast part, the door of the heat treatment furnace is opened, the cast part is taken out, and the time until immersion in the salt bath is 55 seconds or less, Most preferably, it is within 45 seconds, because it takes a pearlite nose in a continuous cooling curve (CCT curve) when it takes more time.
Alternatively, the cooling is performed so as to intersect the pearlite generation start line, and a pearlite structure is generated in the surface layer portion of the cast part, so that a cooling rate that avoids the pearlite nose is ensured. For this, the immersion in the salt bath is within 55 seconds, most preferably within 45 seconds. The salt bath temperature for the isothermal transformation treatment is 250 ° C.
If the temperature is lower than 100 ° C., the toughness is lowered due to martensitic transformation, and if the temperature exceeds 400 ° C., a uniform bainite matrix cannot be obtained. Therefore, the temperature of the molten salt bath is set to 250 to 400 ° C. The holding time in the isothermal transformation process needs to be appropriately set depending on the size of the member to be heat treated, but is generally 0.5 to 3 hours.
【００１６】[0016]
【発明の実施の形態】以下、本発明の実施の形態につい
て実施例に基づいて比較例と共に説明する。本発明にお
いては、予め所定寸法に機械加工をした球状黒鉛鋳鉄鋳
物部品の表層部での脱炭層の生成を防止するために、真
空雰囲気を有する熱処理炉内で、あるいはＲＸガス雰囲
気を有する熱処理炉内でオーステナイト化処理を施し、
前記熱処理炉の開扉からソルトバス中に該鋳物部品を浸
漬するまでの時間を５５秒以内、最も好ましくは４５秒
以内、とすることにより、該鋳物部品の表層部の冷却速
度が連続冷却曲線（ＣＣＴ曲線）におけるパーライトノ
ーズを避けることができ、表層部でのパーライト生成を
防止できるものである。このことにより、熱処理炉内で
の該鋳物部品の表層部の無脱炭の状態を、表層部にパー
ライト組織が生じることなく、そのままソルトバス中に
移動せしめることができ、ソルトバス中における恒温変
態処理によって該鋳物部品の表層部から内部に至るまで
均一なベーナイト組織を確保できるものである。そして
恒温変態処理後は放冷を行う。この一連の熱処理を施す
ことにより、該鋳物部品の表層部には脱炭層（フェライ
ト層）の生成はなく、ソルトバス中における恒温変態処
理によって該部材の表層部から内部に至るまで均一なベ
ーナイト組織を確保できるため、従来のように熱処理後
の機械加工による脱炭層（フェライト層）の削除の必要
がない。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to Comparative Examples based on Examples. In the present invention, in order to prevent the formation of a decarburized layer in the surface layer portion of a spheroidal graphite cast iron casting part that has been machined to a predetermined size in advance, in a heat treatment furnace having a vacuum atmosphere or a heat treatment furnace having an RX gas atmosphere. Austenite treatment is applied in the
By setting the time from the opening of the heat treatment furnace to the immersion of the casting part in the salt bath within 55 seconds, most preferably within 45 seconds, the cooling rate of the surface layer portion of the casting part is a continuous cooling curve. The pearlite nose in the (CCT curve) can be avoided, and the generation of pearlite in the surface layer portion can be prevented. As a result, the non-decarburized state of the surface layer of the cast part in the heat treatment furnace can be moved into the salt bath without forming a pearlite structure in the surface layer, and the isothermal transformation in the salt bath can be performed. By the treatment, it is possible to secure a uniform bainite structure from the surface layer portion to the inside of the cast component. After the isothermal transformation process, cooling is performed. By performing this series of heat treatments, a decarburized layer (ferrite layer) is not formed in the surface layer portion of the casting part, and a uniform bainite structure from the surface layer portion of the member to the inside is obtained by the isothermal transformation treatment in the salt bath. Therefore, it is not necessary to remove the decarburized layer (ferrite layer) by machining after heat treatment as in the conventional case.
【００１７】[0017]
【実施例１】重量比率で、Ｃ３．６％、Ｓｉ２．４％、
Ｍｎ０．４％、Ｃｕ０．５％、Ｍｇ０．０４１％、残部
実質的にＦｅよりなる組成の球状黒鉛鋳鉄のテストピー
ス（図１に示す熱処理炉１内に装入したテストピース５
で、その寸法は２０ｍｍ×２０ｍｍ×１００ｍｍ）に以
下の（１）〜（４）の工程で熱処理を施した。テストピ
ース５の表面処理状態は、脱脂なし、脱炭防止剤なしと
した。 （１）図１に示す熱処理炉１を真空ポンプで真空にしな
がら、テストピース５を熱処理炉１内に装入し、６００
°Ｃまで昇温した。 （２）熱処理炉１の真空度が２×１０-2ｔｏｒｒとな
り、炉内温度が８７５°Ｃにおいて６０分間保持均熱し
てオーステナイト化処理を施した。 （３）次いで、熱処理炉１の扉２を扉開閉装置３により
開き、テストピース５を熱処理炉１から取り出し、直ち
に３８０°Ｃの溶融ソルトバスに搬送装置７を用いて搬
送トレイ８とともに浸漬し、６０分間浸漬保持の恒温変
態処理を施した。ソルトは、ＮａＮＯ2（５０％）とＫ
ＮＯ3（５０％）の共晶組成のもので、融点が１３８〜
１４２°Ｃの硝酸塩系のものを使用した。恒温変態処理
は攪拌装置（図示せず）により攪拌を行いながら実施し
た。なお、熱処理炉１の扉２を開いてからテストピース
５を搬送トレイ８にいれたまま取り出して搬送装置７で
搬送し、ソルトバス６に浸漬するまでの時間は４５秒と
した。 （４）その後、テストピース５を放冷した。Example 1 By weight ratio, C3.6%, Si2.4%,
A test piece of spheroidal graphite cast iron having a composition of Mn 0.4%, Cu 0.5%, Mg 0.041%, and the balance substantially Fe (test piece 5 loaded in heat treatment furnace 1 shown in FIG.
Then, the dimensions were 20 mm × 20 mm × 100 mm) and the heat treatment was performed in the following steps (1) to (4). The surface treatment state of the test piece 5 was set to be no degreasing and no decarburization inhibitor. (1) While the vacuum of the heat treatment furnace 1 shown in FIG.
The temperature was raised to ° C. (2) The degree of vacuum of the heat treatment furnace 1 was 2 × 10 −2 torr, and the temperature inside the furnace was maintained at 875 ° C. for 60 minutes to perform soaking and austenitizing treatment. (3) Next, the door 2 of the heat treatment furnace 1 is opened by the door opening / closing device 3, the test piece 5 is taken out of the heat treatment furnace 1, and immediately immersed in the molten salt bath at 380 ° C. together with the transport tray 8 using the transport device 7. Then, a constant temperature transformation treatment of dipping and holding for 60 minutes was performed. Salt is NaNO 2 (50%) and K
NO 3 (50%) eutectic composition, melting point 138-
A nitrate type of 142 ° C was used. The isothermal transformation process was performed while stirring with a stirring device (not shown). In addition, after the door 2 of the heat treatment furnace 1 was opened, the test piece 5 was taken out in the carrying tray 8 and carried by the carrying device 7, and immersed in the salt bath 6 for 45 seconds. (4) After that, the test piece 5 was allowed to cool.
【００１８】以上の熱処理を施したテストピース５から
２０ｍｍ×２０ｍｍ×２０ｍｍの試験片を採取し、組織
写真を調査した。その結果は、表層部の組織写真を示す
図２（倍率：１００倍）と図３（倍率：４００倍）にみ
るように、均一なベーナイト組織を得ることができた。
また、中心部の組織写真を示す図４（倍率：１００倍）
と図５（倍率：４００倍）でも同様にベーナイト組織を
確保できた。なお、図中の球状のものは球状黒鉛であ
る。なお、表層部での脱炭層の生成は確認できなっかっ
た。本実施例では、鋳鉄のうち球状黒鉛鋳鉄について述
べたが、ネズミ鋳鉄や合金元素を含有する合金鋳鉄等に
ついても本発明を適用できることは当然である。A 20 mm × 20 mm × 20 mm test piece was sampled from the test piece 5 which had been subjected to the above heat treatment, and the structure photograph was investigated. As a result, as shown in FIG. 2 (magnification: 100 times) and FIG. 3 (magnification: 400 times) showing microstructure photographs of the surface layer, a uniform bainite structure could be obtained.
Further, FIG. 4 showing a photograph of the structure of the central portion (magnification: 100 times)
Also in FIG. 5 (magnification: 400 times), the bainite structure was similarly secured. Note that the spherical ones in the figure are spherical graphite. It was not possible to confirm the formation of a decarburized layer in the surface layer. In the present embodiment, the spheroidal graphite cast iron among cast iron has been described, but it goes without saying that the present invention can be applied to gray cast iron, alloy cast iron containing alloy elements, and the like.
【００１９】[0019]
【実施例２】熱処理炉の雰囲気をＲＸガス雰囲気とし、
真空ポンプで減圧しながらあるいは減圧して熱処理を施
した以外は、前述の実施例１と同様の条件で熱処理を施
した。減圧による真空度は１０-1ｔｏｒｒであった。ま
たＲＸガスは通常のＲＸガスを使用した。なお、熱処理
炉１の開扉からテストピース５を取り出して搬送し、ソ
ルトバス６の溶融ソルト９に浸漬するまでの時間は４７
秒とした。熱処理炉の雰囲気をＲＸガス雰囲気とする場
合には、ソルトの分解、場合によってはＲＸガスの分
解、により熱処理炉内雰囲気が汚染されるので、真空ポ
ンプにより減圧した。搬送トレイ８は、ステンレス鋼や
耐熱鋼で製作されているが、繰り返し使用による加熱冷
却のために溶接部等の微細クラック部にソルトがしみこ
んでおり、洗浄してもソルトを完全に除去することは実
際不可能である。熱処理作業毎に新しく製作した搬送ト
レイを使用することは、不経済であり、また現実的でな
いと考えられる。実施例１と同様に、組織写真（図示し
ないが）を確認した結果、表層部、中心部ともに均一な
ベーナイト組織が確保できていた。なお、実施例１と同
様に表層部での脱炭層（フェライト層）の生成は確認で
きなかった。Example 2 The atmosphere of the heat treatment furnace was an RX gas atmosphere,
The heat treatment was performed under the same conditions as in Example 1 above, except that the heat treatment was performed while reducing the pressure with the vacuum pump or reducing the pressure. The degree of vacuum due to reduced pressure was 10 -1 torr. As the RX gas, a normal RX gas was used. It should be noted that the time required for taking out the test piece 5 from the open door of the heat treatment furnace 1 and carrying it and immersing it in the molten salt 9 of the salt bath 6 is 47.
Seconds. When the atmosphere of the heat treatment furnace is the RX gas atmosphere, the atmosphere in the heat treatment furnace is contaminated by the decomposition of the salt and the decomposition of the RX gas in some cases, so the pressure was reduced by the vacuum pump. The transport tray 8 is made of stainless steel or heat-resistant steel, but the salt is soaked in the micro cracks such as the welded part due to repeated heating and cooling, and the salt should be completely removed even after cleaning. Is actually impossible. It is considered uneconomical and impractical to use a newly made carrier tray for each heat treatment operation. As in Example 1, as a result of confirming a structure photograph (not shown), a uniform bainite structure was secured in both the surface layer portion and the central portion. As in Example 1, formation of a decarburized layer (ferrite layer) in the surface layer could not be confirmed.
【００２０】[0020]
【比較例】熱処理炉の雰囲気をＲＸガス雰囲気とし、真
空ポンプによる減圧なしとした以外は、前述の実施例１
と同様の条件で熱処理を施した。なお、熱処理炉１の開
扉からテストピース５を取り出して搬送し、ソルトバス
６の溶融ソルト９に浸漬するまでの時間は４５秒を要し
た。実施例と同様に組織写真（図示しないが）を調査し
た結果、実施例よりも短時間でソルトバスに浸漬したに
もかかわらず、表層部での脱炭層の生成が確認された。
このことは、熱処理炉内で既に脱炭が生じていたものと
考えられる。[Comparative Example] Example 1 described above except that the atmosphere of the heat treatment furnace was an RX gas atmosphere and no pressure reduction was performed by a vacuum pump.
The heat treatment was performed under the same conditions as in. It took 45 seconds for the test piece 5 to be taken out from the open door of the heat treatment furnace 1 to be conveyed and to be immersed in the molten salt 9 of the salt bath 6. As a result of investigating a microstructure photograph (not shown) as in the example, it was confirmed that the decarburized layer was formed in the surface layer portion even though the microstructure was immersed in the salt bath in a shorter time than the example.
This is presumably because decarburization had already occurred in the heat treatment furnace.
【００２１】[0021]
【発明の効果】以上説明したように、球状黒鉛鋳鉄鋳物
部品のオーステナイト化処理を真空雰囲気または減圧Ｒ
Ｘガス雰囲気を有する熱処理炉内で行い、パーライト組
織が生じない冷却速度でソルトバスに浸漬し、恒温処
理、放冷とすることにより、該鋳物部品の表層部には脱
炭層がなく、表層部から内部まで均一なベーナイト組織
を有する無脱炭・耐摩耗性球状黒鉛鋳鉄鋳物部品を得る
ことがでる。このために、熱処理前に該鋳物部品を予め
所定寸法に機械加工しておけば、熱処理後の機械加工を
必要とせず、工数低減にも寄与する。また熱処理後の該
鋳物部品は耐摩耗性に優れるため、鋳鉄本来の特性を発
揮する各種部品や用途に適用できる。As described above, the austenitizing treatment of the spheroidal graphite cast iron casting part is performed in the vacuum atmosphere or the reduced pressure R.
There is no decarburized layer in the surface layer portion of the cast part by performing the treatment in a heat treatment furnace having an X gas atmosphere, immersing in a salt bath at a cooling rate at which a pearlite structure does not occur, and performing constant temperature treatment and cooling. It is possible to obtain decarburization-free and wear-resistant spheroidal graphite cast iron cast parts having a uniform bainite structure from the inside to the inside. For this reason, if the cast component is machined to a predetermined size before the heat treatment, the machining after the heat treatment is not required, which contributes to the reduction of the number of steps. Further, since the cast parts after heat treatment have excellent wear resistance, they can be applied to various parts exhibiting the original characteristics of cast iron and applications.
【図１】本発明に係る真空雰囲気（減圧ＲＸガス雰囲気
も含む）を有する熱処理炉とソルトバスの概略縦断面図
である。FIG. 1 is a schematic vertical cross-sectional view of a heat treatment furnace and a salt bath having a vacuum atmosphere (including a reduced pressure RX gas atmosphere) according to the present invention.
【図２】本発明の実施例の熱処理後の表層部断面の組織
写真（倍率：１００倍）である。FIG. 2 is a structural photograph (magnification: 100 times) of a surface layer section after heat treatment in an example of the present invention.
【図３】本発明の実施例の熱処理後の表層部断面の組織
写真（倍率：４００倍）である。FIG. 3 is a structural photograph (magnification: 400 times) of a cross section of a surface layer portion after heat treatment in an example of the present invention.
【図４】本発明の実施例の熱処理後の中心部断面の組織
写真（倍率：１００倍）である。FIG. 4 is a structural photograph (magnification: 100 times) of a central cross section after heat treatment in an example of the present invention.
【図５】本発明の実施例の熱処理後の中心部断面の組織
写真（倍率：４００倍）である。FIG. 5 is a structural photograph (magnification: 400 times) of a cross section of a central portion after heat treatment in an example of the present invention.
１ 熱処理炉 ２ 熱処理炉の扉 ３ 扉開閉装置 ４ 扉懸架ワイヤ ５ テストピース（熱処理鋳物部品） ６ ソルトバス ７ 搬送装置 ８ 搬送トレイ ９ 溶融ソルト 1 Heat treatment furnace 2 Door of heat treatment furnace 3 Door opening / closing device 4 Door suspension wire 5 Test piece (heat treatment casting part) 6 Salt bath 7 Transfer device 8 Transfer tray 9 Molten salt
Claims (11)
黒鉛鋳鉄鋳物部品を８００〜９５０°Ｃのオーステナイ
ト温度領域に０．５〜３時間保持均熱した後、前記熱処
理炉から取り出し、パーライト組織を生じない冷却速度
でソルトバス中に浸漬し、続いて該ソルトバス中で恒温
変態処理を施し、その後放冷することを特徴とする無脱
炭・耐摩耗性球状黒鉛鋳鉄鋳物部品の製造方法。1. A spheroidal graphite cast iron casting part is held and soaked in an austenite temperature range of 800 to 950 ° C. for 0.5 to 3 hours in a heat treatment furnace having a vacuum atmosphere, and then taken out of the heat treatment furnace to obtain a pearlite structure. A method for producing a decarburization-free and wear-resistant spheroidal graphite cast iron casting part, which is characterized in that it is immersed in a salt bath at a cooling rate that does not cause, followed by constant temperature transformation treatment in the salt bath, and then allowed to cool. .
処理炉内の真空度が１０-1ｔｏｒｒ以上であることを特
徴とする請求項１記載の無脱炭・耐摩耗性球状黒鉛鋳鉄
鋳物部品の製造方法。2. The decarburization-free and wear-resistant spheroidal graphite cast iron casting according to claim 1, wherein the degree of vacuum in the heat treatment furnace having the vacuum atmosphere according to claim 1 is 10 −1 torr or more. Manufacturing method of parts.
が予め所定寸法に機械加工されていることを特徴とする
請求項１又は請求項２に記載の無脱炭・耐摩耗性球状黒
鉛鋳鉄鋳物部品の製造方法。3. The decarburization-free and wear-resistant spheroidal graphite according to claim 1 or 2, wherein the spheroidal graphite cast iron casting part according to claim 1 is machined in advance to a predetermined size. Manufacturing method of cast iron casting parts.
ない冷却速度を達成する手段が、前記真空雰囲気を有す
る熱処理炉の扉を開いて、前記球状黒鉛鋳鉄鋳物部品を
取りだしてからソルトバス中に浸漬するまでの時間を５
５秒以内とすることを特徴とする請求項１乃至請求項３
に記記載の無脱炭・耐摩耗性球状黒鉛鋳鉄鋳物部品の製
造方法。4. The means for achieving a cooling rate without generating a pearlite structure according to claim 1, wherein a door of a heat treatment furnace having the vacuum atmosphere is opened to take out the spheroidal graphite cast iron casting part, and then in a salt bath. Time to soak in 5
It is within 5 seconds.
A method for producing a non-decarburizing / wear-resistant spheroidal graphite cast iron casting part as described in.
を２×１０-2ｔｏｒｒ以上とし、該真空雰囲気内で球状
黒鉛鋳鉄鋳物部品を８００〜９５０°Ｃのオーステナイ
ト温度領域に０．５〜３時間保持均熱した後、前記熱処
理炉から取り出し、パーライト組織を生じない冷却速度
でソルトバス中に浸漬するまでの時間を４５秒以内と
し、続いて該ソルトバス中で恒温変態処理を施し、その
後放冷することを特徴とする無脱炭・耐摩耗性球状黒鉛
鋳鉄鋳物部品の製造方法。5. The degree of vacuum in a heat treatment furnace having a vacuum atmosphere is set to 2 × 10 −2 torr or more, and the spheroidal graphite cast iron casting parts are placed in an austenite temperature region of 800 to 950 ° C. in an amount of 0.5 to 0.5 in the vacuum atmosphere. After holding and soaking for 3 hours, it was taken out from the heat treatment furnace, and the time until it was immersed in a salt bath at a cooling rate at which a pearlite structure was not generated was set to 45 seconds or less, and then a constant temperature transformation treatment was performed in the salt bath. A method for producing a non-decarburizing, wear-resistant spheroidal graphite cast iron casting part, which is characterized by allowing to cool thereafter.
Ｃに溶融したソルトバス中で前記球状黒鉛鋳鉄鋳物部品
を所定時間浸漬して行うことを特徴とする請求項１乃至
請求項５に記記載の無脱炭・耐摩耗性球状黒鉛鋳鉄鋳物
部品の製造方法。6. The isothermal transformation treatment is 250 to 400 °
The spheroidal graphite cast iron casting part is immersed in a salt bath melted in C for a predetermined period of time to perform decarburization-free and wear-resistant spheroidal graphite cast iron cast part according to any one of claims 1 to 5. Production method.
球状黒鉛鋳鉄鋳物部品を８００〜９５０°Ｃのオーステ
ナイト温度領域に０．５〜３時間保持均熱した後、前記
熱処理炉から取り出し、パーライト組織を生じない冷却
速度でソルトバス中に浸漬し、続いて該ソルトバス中で
恒温変態処理を施し、その後放冷することを特徴とする
無脱炭・耐摩耗性球状黒鉛鋳鉄鋳物部品の製造方法。7. A heat treatment furnace having an RX gas atmosphere,
The spheroidal graphite cast iron casting part was kept and soaked in the austenite temperature range of 800 to 950 ° C. for 0.5 to 3 hours, and then taken out from the heat treatment furnace and immersed in a salt bath at a cooling rate that does not generate a pearlite structure. A method for producing a non-decarburization / abrasion resistant spheroidal graphite cast iron casting part, which is characterized in that a constant temperature transformation treatment is performed in the salt bath and then allowed to cool.
が、予め所定寸法に機械加工されていることを特徴とす
る請求項７に記載の無脱炭・耐摩耗性球状黒鉛鋳鉄鋳物
部品の製造方法。8. A decarburization-free and wear-resistant spheroidal graphite cast iron cast part according to claim 7, wherein the spheroidal graphite cast iron cast part according to claim 7 is machined in advance to a predetermined size. Manufacturing method.
ない冷却速度を達成する手段が、前記ＲＸガス雰囲気を
有する熱処理炉の扉を開いて、前記球状黒鉛鋳鉄鋳物部
品を取りだしてからソルトバス中に浸漬するまでの時間
を５５秒以内とすることを特徴とする請求項７又は請求
項８に記記載の無脱炭・耐摩耗性球状黒鉛鋳鉄鋳物部品
の製造方法。9. A means for achieving a pearlite structure-free cooling rate according to claim 7, wherein the door of the heat treatment furnace having the RX gas atmosphere is opened to take out the spheroidal graphite cast iron casting part, and then the salt bath. The method for producing a non-decarburizing / abrasion resistant spheroidal graphite cast iron casting part according to claim 7 or 8, wherein the time until immersion is 55 seconds or less.
で、球状黒鉛鋳鉄鋳物部品を８００〜９５０°Ｃのオー
ステナイト温度領域に０．５〜３時間保持均熱した後、
前記熱処理炉から取り出し、パーライト組織を生じない
冷却速度でソルトバス中に浸漬するまでの時間を４５秒
以内とし、続いて該ソルトバス中で恒温変態処理を施
し、その後放冷することを特徴とする無脱炭・耐摩耗性
球状黒鉛鋳鉄鋳物部品の製造方法。10. A spheroidal graphite cast iron casting part is held and soaked in an austenite temperature range of 800 to 950 ° C. for 0.5 to 3 hours in a heat treatment furnace having an RX gas atmosphere,
It is characterized in that the time taken to remove from the heat treatment furnace and soak it in a salt bath at a cooling rate that does not generate a pearlite structure is within 45 seconds, and subsequently, a constant temperature transformation treatment is performed in the salt bath and then allowed to cool. A method of manufacturing a non-decarburized, wear-resistant spheroidal graphite cast iron casting part.
°Ｃに溶融したソルトバス中で前記球状黒鉛鋳鉄鋳物部
品を所定時間浸漬して行うことを特徴とする請求項７乃
至請求項１０に記記載の無脱炭・耐摩耗性球状黒鉛鋳鉄
鋳物部品の製造方法。11. The isothermal transformation treatment is 250 to 400.
The spheroidal graphite cast iron casting part is immersed in a salt bath melted at ° C for a predetermined period of time to perform decarburization-free and wear-resistant spheroidal graphite cast iron cast part according to any one of claims 7 to 10. Manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11990596A JPH09302411A (en) | 1996-05-15 | 1996-05-15 | Production of non-decarburized and wear resistant spheroidal graphite cast iron casting parts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11990596A JPH09302411A (en) | 1996-05-15 | 1996-05-15 | Production of non-decarburized and wear resistant spheroidal graphite cast iron casting parts |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09302411A true JPH09302411A (en) | 1997-11-25 |
Family
ID=14773116
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11990596A Pending JPH09302411A (en) | 1996-05-15 | 1996-05-15 | Production of non-decarburized and wear resistant spheroidal graphite cast iron casting parts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09302411A (en) |
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|---|---|---|---|---|
| JP2013503975A (en) * | 2009-10-05 | 2013-02-04 | バイエリッシュ モトーレン ヴェルケ アクチエンゲゼルシャフト | Cast iron cast part and method of manufacturing the same |
| JP2015232151A (en) * | 2014-06-09 | 2015-12-24 | 日野自動車株式会社 | Method for producing cast iron member |
| CN108559903A (en) * | 2018-05-29 | 2018-09-21 | 河南工程学院 | Cooling bainite ductile iron cylinder jacket of a kind of control and preparation method thereof |
| CN112267059A (en) * | 2020-10-17 | 2021-01-26 | 安徽军明机械制造有限公司 | Treatment process for enhancing mechanical property of nodular cast iron |
| CN115341080A (en) * | 2022-08-24 | 2022-11-15 | 唐山鑫业科技有限公司 | Decarburization process for white malleable cast iron |
-
1996
- 1996-05-15 JP JP11990596A patent/JPH09302411A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013503975A (en) * | 2009-10-05 | 2013-02-04 | バイエリッシュ モトーレン ヴェルケ アクチエンゲゼルシャフト | Cast iron cast part and method of manufacturing the same |
| JP2015232151A (en) * | 2014-06-09 | 2015-12-24 | 日野自動車株式会社 | Method for producing cast iron member |
| CN108559903A (en) * | 2018-05-29 | 2018-09-21 | 河南工程学院 | Cooling bainite ductile iron cylinder jacket of a kind of control and preparation method thereof |
| CN108559903B (en) * | 2018-05-29 | 2020-04-10 | 河南工程学院 | Cooling-controlled bainite nodular cast iron cylinder sleeve and preparation method thereof |
| CN112267059A (en) * | 2020-10-17 | 2021-01-26 | 安徽军明机械制造有限公司 | Treatment process for enhancing mechanical property of nodular cast iron |
| CN115341080A (en) * | 2022-08-24 | 2022-11-15 | 唐山鑫业科技有限公司 | Decarburization process for white malleable cast iron |
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