JP2015203138A - Iron casting and manufacturing method therefor - Google Patents
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本発明は鋳鉄鋳物とその製造方法に関する。 The present invention relates to a cast iron casting and a manufacturing method thereof.
高硬度で耐摩耗性、耐肌荒れ性を必要とする厚肉鋳物として、Ｃｒ、Ｍｏ、Ｖ、Ｗ、Ｃｏ、Ｎｂなどを含有させた鋳鉄鋳物が従来から提供されている。 Conventionally, cast iron castings containing Cr, Mo, V, W, Co, Nb, and the like have been provided as thick castings that require high hardness, wear resistance, and rough skin resistance.
例えば下記特許文献１には、熱間圧延用複合ロールの外層材としてＣ、Ｓｉの他、Ｍｎ、Ｃｒ、Ｍｏ、Ｖ、Ｗ、Ｎｉ、Ｃｏ、Ｎｂを含有するハイス系鋳鉄を用い、これを一旦加熱してオーステナイト化した後、２００〜３００℃に焼入れし、その後５００〜５５０℃で各１０時間の焼戻しを複数回繰り返して、マルテンサイト又はベイナイトと２次炭化物析出させた組織とし、硬度を８０Ｈｓ以上とするものが開示されている。
また本出願人の以前の出願に係る下記特許文献２には、鋳鉄鋳物の製造方法としてＣ、Ｓｉの他、Ｍｎ、Ｃｒ、Ｍｏ、Ｖを含有する鋳鋼を用い、これを一旦加熱してオーステナイト化した後、冷却し、４５０〜５４０℃で２０〜１４０時間保持した後、常温まで冷却することで、基地の８０％以上をマルテンサイト相とし、硬度を７４Ｈｓ以上とするものが開示されている。
For example, in Patent Document 1 below, high-speed cast iron containing Mn, Cr, Mo, V, W, Ni, Co, and Nb in addition to C and Si is used as an outer layer material of a composite roll for hot rolling. Once heated to austenite, it is quenched to 200 to 300 ° C., and then tempering at 500 to 550 ° C. for 10 hours each is repeated a plurality of times to obtain martensite or bainite and secondary carbide precipitated structure, and the hardness is increased. What makes 80Hs or more is disclosed.
Further, in the following Patent Document 2 relating to the previous application of the present applicant, a cast steel containing Mn, Cr, Mo, V in addition to C and Si is used as a method for producing a cast iron casting, which is once heated to austenite. After cooling, it is cooled, held at 450 to 540 ° C. for 20 to 140 hours, and then cooled to room temperature, so that 80% or more of the base is a martensite phase and the hardness is 74 Hs or more. .
しかしながら上記特許文献１の発明においては、Ｃ、Ｓｉ、Ｍｎ、Ｃｒ、Ｍｏ、Ｖの他にＷ、Ｎｉ、Ｃｏ、Ｎｂを含有させる必要があること、焼入れによる割れを防ぐために比較的冷却速度の遅い焼入れを行うことに伴って、残留オーステナイトが多くなるので、複数回に及ぶ焼戻し処理を行って、組織の改善と硬度向上を行わなければならないという問題があった。
また上記特許文献２の発明においては、成分組成的にはＶが入っていること、また熱処理的には４５０〜５４０℃で２０〜１４０時間保持することで残留オーステナイトを減らしているが、２０時間以上の保持時間は長く、コスト高となる。
However, in the invention of Patent Document 1, it is necessary to contain W, Ni, Co, Nb in addition to C, Si, Mn, Cr, Mo, V, and a relatively low cooling rate to prevent cracking due to quenching. Accompanying the slow quenching, the amount of retained austenite increases, so that there has been a problem that the structure must be improved and the hardness increased by performing tempering multiple times.
In the invention of the above-mentioned Patent Document 2, the residual austenite is reduced by holding V at the component composition and holding at 450 to 540 ° C. for 20 to 140 hours in terms of heat treatment. The above holding time is long and the cost is high.
そこで本発明は上記従来の問題点を解消し、焼割れが生じ難く、且つ複数回に及ぶ焼戻し処理や焼入れ途中に残留オーステナイトを減らすための長時間の保持を行わなくても、マルテンサイト相が多く且つ残留オーステナイト相が少なく、よって所定の高硬度で、耐摩耗性に優れ、厚肉鋳物に適した鋳鉄鋳物とその製造方法の提供を課題とする。 Therefore, the present invention solves the above-mentioned conventional problems, is hard to cause tempering cracks, and the martensite phase can be obtained without performing tempering and holding for a long time to reduce retained austenite during quenching. An object of the present invention is to provide a cast iron casting having a large amount and a small residual austenite phase, having a predetermined high hardness, excellent wear resistance, and suitable for a thick casting, and a manufacturing method thereof.
上記課題を解決する本発明の鋳鉄鋳物は、重量％で、Ｃ：１．０〜２．５％、Ｓｉ：０．２〜１．５％、Ｍｎ：０．２〜１．５％、Ｎｉ：０．５〜３．０％、Ｃｒ：５．０〜９．０％、Ｍｏ：０．８〜２．５％、を含有し、残部がＦｅからなる成分組成を有し、基地中に８０％以上のマルテンサイト相と２０％未満の残留オーステナイト相を含むと共に、金属炭化物が分散した組織からなり、且つ硬度が７４Ｈｓ以上であることを第１の特徴としている。
また本発明の鋳鉄鋳物は、上記第１の特徴に加えて、重量％で、Ｃ：１．２〜２．３％、Ｓｉ：０．４〜１．３％、Ｍｎ：０．４〜１．３％、Ｎｉ：１．０〜２．５％、Ｃｒ：５．５〜８．５％、Ｍｏ：０．９〜２．４％、を含有し、残部がＦｅからなる成分組成を有し、基地中に８５％以上のマルテンサイト相と１５％未満の残留オーステナイト相を含むと共に、金属炭化物が分散した組織からなり、且つ硬度が７４〜８７Ｈｓであることを第２の特徴としている。
また本発明の鋳鉄鋳物は、上記第１又は第２の特徴に加えて、肉厚が１００ｍｍ以上の厚肉部分を有することを第３の特徴としている。
また本発明の鋳鉄鋳物の製造方法によれば、上記第１〜第３の特徴の何れかに記載の鋳鉄鋳物の製造方法であって、予め成分組成を調整してなる鋳造物を９５０〜１１００℃まで加熱してオーステナイト化した後、冷却速度を１０〜４３℃／分として、４５０〜５４０℃にまで冷却し、その温度で少なくとも１４０時間以下の短時間保持した後若しくは保持することなく、常温まで冷却するようにしたことを第４の特徴としている。
また本発明の鋳鉄鋳物の製造方法によれば、上記第４の特徴に加えて、予め成分組成を調整してなる鋳造物を９７０〜１０８０℃まで加熱してオーステナイト化した後、冷却速度を１３〜３１℃／分として、４７０〜５２５℃まで冷却し、その温度で少なくとも５０時間以下の短時間保持した後若しくは保持することなく、常温まで冷却するようにしたことを第５の特徴としている。
また本発明の鋳鉄鋳物の製造方法によれば、上記第５の特徴に加えて、予め成分組成を調整してなる鋳造物を９９０〜１０６０℃まで加熱してオーステナイト化した後、冷却速度を１６〜２３℃／分として、４９０〜５１０℃まで冷却し、その温度で少なくとも２０時間未満の短時間保持した後若しくは保持することなく、常温まで冷却するようにしたことを第６の特徴としている。
The cast iron casting of the present invention that solves the above problems is, by weight, C: 1.0-2.5%, Si: 0.2-1.5%, Mn: 0.2-1.5%, Ni : 0.5 to 3.0%, Cr: 5.0 to 9.0%, Mo: 0.8 to 2.5%, and the balance has a component composition consisting of Fe, The first feature is that it contains a martensite phase of 80% or more and a residual austenite phase of less than 20%, has a structure in which metal carbide is dispersed, and has a hardness of 74 Hs or more.
Moreover, in addition to the said 1st characteristic, the cast iron casting of this invention is C: 1.2-2.3%, Si: 0.4-1.3%, Mn: 0.4-1 in weight%. 0.3%, Ni: 1.0 to 2.5%, Cr: 5.5 to 8.5%, Mo: 0.9 to 2.4%, and the balance is composed of Fe. The second feature is that the base contains a martensite phase of 85% or more and a residual austenite phase of less than 15%, has a structure in which metal carbide is dispersed, and has a hardness of 74 to 87 Hs.
In addition to the first or second feature, the cast iron casting of the present invention has a third feature that it has a thick portion with a thickness of 100 mm or more.
Moreover, according to the cast iron casting manufacturing method of the present invention, the cast iron casting manufacturing method according to any one of the first to third features, wherein the casting obtained by adjusting the component composition in advance is 950 to 1100. After heating to 0 ° C. and austenite, cooling to 450 to 540 ° C. at a cooling rate of 10 to 43 ° C./min, after holding at that temperature for at least 140 hours or less for a short time or at normal temperature The fourth feature is that the cooling is performed.
Further, according to the method for producing a cast iron casting of the present invention, in addition to the fourth feature, the casting obtained by previously adjusting the component composition is heated to 970 to 1080 ° C. to austenite, and then the cooling rate is 13 The fifth feature is that it is cooled to 470 to 525 ° C. at ˜31 ° C./min, and is cooled to room temperature after being held at that temperature for a short time of at least 50 hours or less, or without being held.
According to the method for producing a cast iron casting of the present invention, in addition to the fifth feature, the casting obtained by previously adjusting the component composition is heated to 990 to 1060 ° C. to austenite, and then the cooling rate is 16 The sixth feature is that it is cooled to 490-510 ° C. at -23 ° C./min, and is cooled to room temperature after being held at that temperature for a short time of at least less than 20 hours or without being held.
請求項１に記載の鋳鉄鋳物によれば、そこに示された成分組成、相構成、硬度構成により、Ｎｉは含むが、Ｗ、Ｃｏ、Ｎｂを含まない合金鋳鉄鋳物として、焼割れが生じ難く、また複数回に及ぶ焼戻し処理を行わなくても、残留オーステナイト相を十分に少なく且つマルテンサイト相を十分に多くし、且つ金属炭化物を分散させることで、所望の高硬度で、耐摩耗性に優れ、厚肉鋳物にも適した鋳鉄鋳物を現に提供することができる。
また請求項２に記載の鋳鉄鋳物によれば、上記請求項１の構成による作用効果に加えて、成分組成、相構成、硬度構成をより好ましい範囲に限定することで、より焼割れが生じ難く、複数回に及ぶ焼戻し処理を行わなくても、残留オーステナイト相がより少なく且つマルテンサイト相がより多く、よってより高硬度で、耐摩耗性に優れ、厚肉鋳物にも適した鋳鉄鋳物を安定して提供することができる。
また請求項３に記載の鋳鉄鋳物によれば、上記請求項２の構成による作用効果に加えて、更に成分組成、相構成、硬度構成を限定することで、一層且つ更に安定して、焼割れが生じ難く、複数回に及ぶ焼戻し処理を行わなくても、残留オーステナイト相が少なく且つマルテンサイト相が多く、高硬度で、耐摩耗性に優れ、厚肉鋳物にも適した鋳鉄鋳物を提供することができる。
According to the cast iron casting of claim 1, due to the component composition, phase configuration, and hardness configuration shown therein, Ni is included, but as an alloy cast iron cast not containing W, Co, or Nb, it is difficult to cause cracking. In addition, even if tempering is not performed multiple times, the retained austenite phase is sufficiently reduced, the martensite phase is sufficiently increased, and the metal carbide is dispersed to achieve desired high hardness and wear resistance. It is possible to provide a cast iron casting that is excellent and suitable for a thick casting.
Moreover, according to the cast iron casting of Claim 2, in addition to the effect by the structure of the said Claim 1, by limiting a component composition, a phase structure, and a hardness structure to a more preferable range, it is hard to produce a burning crack. Even without tempering multiple times, there is less retained austenite phase and more martensite phase, thus stabilizing cast iron castings with higher hardness, better wear resistance and suitable for thick castings Can be provided.
Moreover, according to the cast iron casting of claim 3, in addition to the operational effects of the configuration of claim 2, the component composition, phase configuration, and hardness configuration are further limited, so Provided is a cast iron casting that has a low residual austenite phase and a large amount of martensite phase, has high hardness, is excellent in wear resistance, and is suitable for thick-walled castings even without performing tempering treatment multiple times. be able to.
また請求項４に記載の鋳鉄鋳物の製造方法によれば、上記請求項１〜３の何れかに記載の鋳造鋳物の製造方法であって、予め成分組成を調整してなる鋳造物を９５０〜１１００℃まで加熱してオーステナイト化した後、冷却速度を１０〜４３℃／分として、４５０〜５４０℃にまで冷却し、その温度で少なくとも１４０時間以下の短時間保持した後若しくは保持することなく、常温まで冷却するようにしたので、
焼戻し処理を複数回繰り返すような熱処理を行うことなく、短時間の熱処理で、焼割れが生じ難く、残留オーステナイト相が少なく且つマルテンサイト相が多く、よって高硬度で、耐摩耗性に優れ、厚肉鋳物にも適した鋳鉄鋳物を現に製造することができる。
また請求項５に記載の鋳鉄鋳物の製造方法によれば、上記請求項４に記載の構成による作用効果に加えて、製造条件をより好ましい条件に限定することで、より短時間の熱処理で、より安定して確実に、焼割れが生じ難く、厚肉鋳物に適した鋳鉄鋳物を提供することができる。
また請求項６に記載の鋳鉄鋳物の製造方法によれば、上記請求項４に記載の構成による作用効果に加えて、製造条件を更に好ましい条件に限定することで、２０時間未満のより短時間の熱処理で、更に安定して確実に、焼割れが生じ難く、厚肉鋳物にも適した鋳鉄鋳物を提供することができる。
Moreover, according to the manufacturing method of the cast iron casting of Claim 4, it is a manufacturing method of the casting casting in any one of the said Claims 1-3, Comprising: The casting formed by adjusting a component composition beforehand is 950-500. After heating to 1100 ° C. to austenite, cooling to 450-540 ° C., with a cooling rate of 10-43 ° C./min, and after holding at that temperature for at least 140 hours or less, or without holding, Since it was cooled to room temperature,
Without heat treatment that repeats tempering treatment multiple times, heat cracking is difficult to occur in a short time heat treatment, there are few residual austenite phases and many martensite phases, and thus high hardness, excellent wear resistance, thick A cast iron casting suitable for meat casting can actually be produced.
Further, according to the method for producing a cast iron casting according to claim 5, in addition to the function and effect of the configuration according to claim 4, by limiting the production conditions to more preferable conditions, the heat treatment can be performed in a shorter time, It is possible to provide a cast iron casting that is more stable and reliable and that is less likely to cause cracking and that is suitable for thick castings.
According to the method for producing a cast iron casting according to claim 6, in addition to the function and effect of the structure according to claim 4, the production conditions are further limited to more preferable conditions, so that the production time can be shortened to less than 20 hours. With this heat treatment, it is possible to provide a cast iron casting that is more stable and reliable, is less likely to cause cracking, and is suitable for thick castings.
本発明の鋳鉄鋳物とその製造法について、まず使用する鋳鉄材料の成分組成における各成分元素の含有範囲の限定理由を以下に説明する。 Regarding the cast iron casting of the present invention and the manufacturing method thereof, the reasons for limiting the content ranges of the respective component elements in the component composition of the cast iron material to be used will be described below.
Ｃの含有量は、１．０〜２．５重量％とする。
ＣはＣｒ、Ｍｏと結合して、高硬度な炭化物を形成するのに有効である。１．０重量％未満では所望の硬さが得られない。一方、２．５重量％を超えると靭性が低下し、且つ冷却の遅い厚肉鋳物では焼入れ性が低下する。
Ｃの含有量は、硬度、靱性、焼入れ性を考慮して、１．２〜２．３重量％がより好ましく、更に好ましくは１．５〜２．０重量％とする。
The C content is 1.0 to 2.5% by weight.
C is effective for forming a high-hardness carbide by combining with Cr and Mo. If it is less than 1.0% by weight, the desired hardness cannot be obtained. On the other hand, if it exceeds 2.5% by weight, the toughness is lowered, and the hardenability is lowered in a thick casting with slow cooling.
The content of C is preferably 1.2 to 2.3% by weight, more preferably 1.5 to 2.0% by weight in consideration of hardness, toughness, and hardenability.
Ｓｉの含有量は、０．２〜１．５重量％とする。
Ｓｉは、溶湯の脱酸と鋳造性を改善するために０．２重量％以上必要である。１．５重量％を超えると、靭性が低下する。
Ｓｉの含有量は、脱酸能、鋳造性、靱性を考慮して、０．４〜１．３重量％がより好ましく、更に好ましくは０．６〜１．１重量％とする。
The Si content is 0.2 to 1.5% by weight.
Si is required to be 0.2% by weight or more in order to improve the deoxidation and castability of the molten metal. When it exceeds 1.5% by weight, the toughness decreases.
The content of Si is more preferably 0.4 to 1.3% by weight, still more preferably 0.6 to 1.1% by weight in consideration of deoxidizing ability, castability, and toughness.
Ｍｎの含有量は、０．２〜１．５重量％とする。
Ｍｎは溶湯の脱酸脱硫のために０．２重量％以上必要である。また１．５重量％を超えると靭性が低下する。
Ｍｎの含有量は、脱酸脱硫、靱性を考慮して、０．４〜１．３重量％がより好ましく、更に好ましくは０．６〜１．１重量％とする。
The Mn content is 0.2 to 1.5% by weight.
Mn is required to be 0.2% by weight or more for deoxidation and desulfurization of the molten metal. On the other hand, if it exceeds 1.5% by weight, the toughness decreases.
The content of Mn is more preferably 0.4 to 1.3% by weight and further preferably 0.6 to 1.1% by weight in consideration of deoxidation desulfurization and toughness.
Ｎｉの含有量は、０．５〜３．０重量％とする。
Ｎｉは焼入れ性を向上させ、焼入れ中の保持時間が短くても所定の焼入れを容易に行うことができる。このため保持時間が短くても所定の焼入れ硬化を得ることができる。０．５重量％未満では焼入れ性の効果が得られない。一方、３．０重量％を超えると、Ｎｉはオーステナイトを安定にする効果があるため、焼入れ後に残留オーステナイト相が増え、硬度が低下する。
Ｎｉの含有量は、焼入れ性の向上と残留オーステナイト相の増加防止を考慮して、１．０〜２．５重量％がより好ましく、更に好ましくは１．５〜２．０重量％とする。
The Ni content is 0.5 to 3.0% by weight.
Ni improves the hardenability, and even if the holding time during quenching is short, predetermined quenching can be easily performed. For this reason, even if holding time is short, predetermined hardening hardening can be obtained. If it is less than 0.5% by weight, the effect of hardenability cannot be obtained. On the other hand, if it exceeds 3.0% by weight, Ni has an effect of stabilizing austenite, so that the retained austenite phase increases after quenching and the hardness decreases.
The content of Ni is more preferably 1.0 to 2.5% by weight, still more preferably 1.5 to 2.0% by weight, in consideration of improvement in hardenability and prevention of increase in retained austenite phase.
Ｃｒの含有量は、５．０〜９．０重量％とする。
Ｃｒは共晶炭化物を形成し、硬さを高める効果がある。一部は基地中に固溶して焼入れ性を向上させる。５．０重量％未満では前述の効果が得られない。また９．０重量％を超えると共晶炭化物が多すぎ、靭性を劣化させる。
Ｃｒの含有量は、焼入れ性、靱性を考慮して、５．５〜８．５重量％がより好ましく、更に好ましくは６．０〜８．０重量％とする。
The Cr content is 5.0 to 9.0% by weight.
Cr forms an eutectic carbide and has the effect of increasing the hardness. Some are dissolved in the base to improve hardenability. If it is less than 5.0% by weight, the above-mentioned effects cannot be obtained. On the other hand, if it exceeds 9.0% by weight, the amount of eutectic carbide is too much and the toughness is degraded.
In view of hardenability and toughness, the Cr content is more preferably 5.5 to 8.5% by weight, still more preferably 6.0 to 8.0% by weight.
Ｍｏの含有量は、０．８〜２．５重量％とする。
Ｍｏは基地中に固溶して焼入れ性を向上させ、焼戻し軟化抵抗を増す。０．８重量％未満では前述の効果が得られない。また２．５重量％を超えると基地中への固溶は飽和し、共晶炭化物が靭性を劣化させる。
Ｍｏの含有量は、焼入れ性、焼戻し軟化抵抗、靱性を考慮して、より好ましくは０．９〜２．４重量％、更に好ましくは１．０〜２．３重量％、特に好ましくは１．０〜２．０重量％とするのがよい。
The Mo content is 0.8 to 2.5% by weight.
Mo is dissolved in the base to improve hardenability and increase temper softening resistance. If it is less than 0.8% by weight, the above-mentioned effects cannot be obtained. If it exceeds 2.5% by weight, the solid solution in the matrix is saturated, and the eutectic carbide deteriorates toughness.
The Mo content is more preferably 0.9 to 2.4% by weight, still more preferably 1.0 to 2.3% by weight, and particularly preferably 1.% by weight in consideration of hardenability, temper softening resistance, and toughness. It is good to set it as 0 to 2.0 weight%.
本発明の成分組成において、得られる鋳物中に生じる金属炭化物は、クロム炭化物（Ｃｒ７Ｃ３）、モリブデン炭化物（Ｍｏ２Ｃ）、鉄炭化物（Ｆｅ３Ｃ）である。これらの金属炭化物の合計は、面積率で５〜３０％の範囲とする。３０％を超えると鋳物の靭性が悪くなる。また５％未満では、耐摩耗性が悪くなる。
金属炭化物の合計は面積率で、好ましくは８〜２５％、更に好ましくは１０〜２０％の範囲がよい。
In the component composition of the present invention, metal carbides generated in the resulting casting are chromium carbide (Cr 7 C 3 ), molybdenum carbide (Mo 2 C), and iron carbide (Fe 3 C). The total of these metal carbides is 5 to 30% in terms of area ratio. If it exceeds 30%, the toughness of the casting deteriorates. If it is less than 5%, the wear resistance is poor.
The total of the metal carbides is an area ratio, preferably 8 to 25%, more preferably 10 to 20%.
次に上述の成分組成の鋳鉄材料を用いた鋳造鋳物の製造方法について説明する。
製造方法は、図１に示す熱処理図を参照して、上述の成分組成に調整した鋳鉄材料からなる鋳造物を用い、これを９５０〜１１００℃の温度に加熱してオーステナイト化した後、冷却速度を１０〜４３℃／分として、４５０〜５４０℃まで冷却し、その温度で１４０時間未満の短時間保持した後、若しくは保持することなく、放冷して常温まで冷却する。
このような熱処理により、割れが生じ難く、また残留オーステナイト相が少なく且つマルテンサイト相が多い組織となって、高硬度で、耐摩耗性に優れ、厚肉鋳物にも適した鋳鉄鋳物を安定して得ることができる。また複数回の焼戻し処理等を行うことなく、残留オーステナイト相を低減し、マルテンサイト相の多い組織を得ることができる。
Next, a method for producing a cast casting using the cast iron material having the above component composition will be described.
With reference to the heat treatment diagram shown in FIG. 1, the manufacturing method uses a casting made of a cast iron material adjusted to the above-described component composition, and heats it to a temperature of 950 to 1100 ° C. to austenite, and then cools the cooling rate. Is cooled to 450 to 540 ° C. at a temperature of 10 to 43 ° C./min, and after being held for a short time of less than 140 hours at that temperature, or without being held, it is allowed to cool to room temperature.
Such heat treatment makes it difficult for cracks to occur, has a structure with little retained austenite phase and many martensite phases, and stabilizes cast iron castings with high hardness, excellent wear resistance, and suitable for thick castings. Can be obtained. Moreover, a residual austenite phase can be reduced and a structure | tissue with many martensite phases can be obtained, without performing tempering process etc. of multiple times.
上記の製造方法において、得られる鋳鉄鋳物の基地中におけるマルテンサイト相は８０％以上を占めるようにする。その一方、残留オーステナイト相は２０％未満となるようにする。
マルテンサイト相が８０％未満の場合は、７４Ｈｓ以上の硬度を得ることが難しくなる。勿論、残留オーステナイト相が２０％以上となる場合は、マルテンサイト相が８０％を下回り、所望の硬度を得ることができない。
マルテンサイト相は、好ましくは８５％以上とし、更に好ましくは９０％以上になるようにするのが良い。この場合において、残留オーステナイト相は、それぞれ１５％未満、１０％未満となるようにする。このようにすることで、硬度を確実に７４〜８７Ｈｓにすることができる。
In the production method described above, the martensite phase in the base of the cast iron casting obtained occupies 80% or more. On the other hand, the residual austenite phase should be less than 20%.
When the martensite phase is less than 80%, it is difficult to obtain a hardness of 74 Hs or more. Of course, when the retained austenite phase is 20% or more, the martensite phase is less than 80% and the desired hardness cannot be obtained.
The martensite phase is preferably 85% or more, and more preferably 90% or more. In this case, the residual austenite phase is less than 15% and less than 10%, respectively. By doing in this way, hardness can be reliably set to 74-87Hs.
前記加熱温度が９５０℃未満では基地中のＣ濃度が低下し、硬さが低下する。更に基地中のＣｒ、Ｍｏ濃度も低下し、焼入れ性が悪くなる。一方、１１００℃を超える温度では合金濃度が濃化した部分が溶融し、変形し易くなる。
加熱温度は、基地中のＣ、Ｃｒ、Ｍｏ濃度等を考慮して、９７０〜１０８０℃が好ましく、更に好ましくは９９０〜１０６０℃とする。
加熱時間は２〜５時間とすることができる。しかし、この時間に限定されるものではなく、加熱によってオーステナイト化できればよい。
When the heating temperature is less than 950 ° C., the C concentration in the base is lowered and the hardness is lowered. Furthermore, the Cr and Mo concentrations in the base also decrease, and the hardenability deteriorates. On the other hand, when the temperature exceeds 1100 ° C., the portion where the alloy concentration is concentrated is melted and easily deformed.
The heating temperature is preferably 970 to 1080 ° C., more preferably 990 to 1060 ° C., considering the C, Cr, Mo concentration in the base.
The heating time can be 2 to 5 hours. However, it is not limited to this time, and it is sufficient if it can be austenitized by heating.
前記加熱後の冷却保持温度が４５０℃未満ではベイナイト変態が起こり易くなり、硬度が低下する。一方、冷却保持温度が５４０℃を越えるとパーライト変態が起こり易くなる。
前記加熱後の冷却保持温度は、マルテンサイト化を考慮して、４７０〜５２５℃が好ましく、更に好ましくは４９０〜５１０℃とする。
When the cooling holding temperature after the heating is less than 450 ° C., bainite transformation is likely to occur, and the hardness decreases. On the other hand, when the cooling holding temperature exceeds 540 ° C., pearlite transformation tends to occur.
The cooling holding temperature after the heating is preferably 470 to 525 ° C., more preferably 490 to 510 ° C. in consideration of martensite formation.
前記加熱温度から冷却保持温度までの冷却速度は、加熱温度９５０〜１１００℃から冷却保持温度４５０〜５４０℃までの冷却を、１５〜４０分、即ち冷却速度を４３℃／分〜１０℃／分で行う。
加熱後の冷却速度が４５０℃まで１５分、即ち４３℃／分より早いと、急激な熱収縮により割れる可能性が高い。一方、５４０℃まで４０分、即ち１０℃／分より遅いと、パーライト変態が起こり、硬さが低下する。
加熱後の冷却速度は、速度が速すぎる場合の冷却時の割れ、遅すぎる場合のパーライト変態の発生を考慮して、加熱温度９７０〜１０８０℃から冷却温度４７０〜５２５℃までの冷却を、２０〜３５分、即ち冷却速度３１℃／分〜１３℃／分で行うのがより好ましい。
更に好ましくは、加熱温度９９０〜１０６０℃から冷却保持温度４９０〜５１０℃までの冷却を、２５〜３０分、即ち冷却速度２３℃／分〜１６℃／分で行うのがよい。
The cooling rate from the heating temperature to the cooling holding temperature is 15 to 40 minutes for cooling from the heating temperature 950 to 1100 ° C. to the cooling holding temperature 450 to 540 ° C., that is, the cooling rate is 43 ° C./min to 10 ° C./min. To do.
When the cooling rate after heating is 15 minutes to 450 ° C., that is, faster than 43 ° C./min, there is a high possibility of cracking due to rapid thermal shrinkage. On the other hand, if it is 40 minutes up to 540 ° C., that is, slower than 10 ° C./minute, pearlite transformation occurs and the hardness decreases.
The cooling rate after heating is 20 ° C. from the heating temperature of 970 to 1080 ° C. to the cooling temperature of 470 to 525 ° C. in consideration of cracking during cooling when the rate is too high and pearlite transformation when it is too slow. More preferably, it is carried out at a cooling rate of 31 ° C./min to 13 ° C./min.
More preferably, cooling from a heating temperature of 990 to 1060 ° C. to a cooling holding temperature of 490 to 510 ° C. is performed for 25 to 30 minutes, that is, at a cooling rate of 23 ° C./min to 16 ° C./min.
前記冷却保持温度での保持時間は０時間でもよい。０時間でも硬度を７４Ｈｓ以上とすることができる。
冷却保持時間が１４０時間を超えるとパーライト変態が生じ、硬さが低下して好ましくない。保持時間を１４０時間以内とすることで、硬度が７４〜８７Ｈｓ程度の鋳鉄鋳物を得ることができる。
一般的には、上記した冷却保持温度での保持時間が短い場合には、ＣｒやＭｏ等による金属炭化物の析出、成長が少なくなることから、冷却保持温度におけるオーステナイト相中の炭素量の低下が少なくなり、その分だけマルテンサイト変態が起こり難く、残留オーステナイトが多く残る傾向となる。が、本発明の場合には、成分組成の調整により、２０時間未満の保持時間としても、８０％以上のマルテンサイト相と２０％未満の残留オーステナイト相からなる硬度が７４Ｈｓ以上の鋳鉄鋳物を得ることができるのである。
保持時間は、マルテンサイト変態による十分な焼入れ硬化、即ち硬度が７４Ｈｓ以上への硬化と、処理時間の短縮、エネルギーコスト等を考慮して、５０時間以内の短時間保持がより好ましく、更に好ましくは２０時間未満の短時間保持とするのが良い。本発明では２０時間未満の保持時間でも硬度が７４Ｈｓ以上を達成できる。
The holding time at the cooling holding temperature may be 0 hour. The hardness can be 74Hs or more even at 0 hours.
When the cooling holding time exceeds 140 hours, pearlite transformation occurs and the hardness decreases, which is not preferable. By setting the holding time within 140 hours, a cast iron casting having a hardness of about 74 to 87 Hs can be obtained.
Generally, when the holding time at the cooling holding temperature described above is short, the precipitation and growth of metal carbides due to Cr, Mo, etc. are reduced, so that the amount of carbon in the austenite phase at the cooling holding temperature is reduced. The martensite transformation hardly occurs and the retained austenite tends to remain. However, in the case of the present invention, by adjusting the component composition, a cast iron casting having a hardness of 74Hs or more consisting of a martensite phase of 80% or more and a retained austenite phase of less than 20% is obtained even with a holding time of less than 20 hours. It can be done.
The holding time is more preferably quench hardening by martensite transformation, that is, hardening to a hardness of 74Hs or more, shortening of processing time, energy cost, etc., and holding for a short time within 50 hours is more preferable. It is good to keep it for a short time of less than 20 hours. In the present invention, a hardness of 74 Hs or more can be achieved even with a holding time of less than 20 hours.
熱処理後に得られる鋳造鋳物の基地組織は、マルテンサイト相が８０％以上、残りが残留オーステナイト相、ベイナイト相、その他となる。ベイナイト相、その他は量が少ない。ベイナイト相は保持温度での保持後の冷却の際に発生することがあるが、その量はごく僅かである。
一方で、上記した金属炭化物が分散した組織となる。
このような組織バランスと成分組成を持つことで、硬度が７４Ｈｓ以上で、高硬度で、耐摩耗性に優れ、肉厚が１００ｍｍ以上の厚肉鋳物にも適したものとなる。
The base structure of the cast casting obtained after the heat treatment has a martensite phase of 80% or more and the remaining austenite phase, bainite phase, and others. The amount of bainite phase and others is small. The bainite phase may occur during cooling after holding at the holding temperature, but its amount is negligible.
On the other hand, the above-described metal carbide is dispersed.
By having such a structure balance and component composition, the hardness is 74Hs or higher, high hardness, excellent wear resistance, and suitable for thick castings having a wall thickness of 100 mm or more.
実施例１〜４、比較例１〜１６の各鋳鉄材料を、表１に示すような成分組成となるように鋳造した。その後、基地組織と硬度調整のため、図１と表２に示す熱処理を施した。
実施例１〜４、比較例１〜１６と熱処理パターンＡ〜Ｎの組み合わせによって得られた鋳鉄鋳物の硬度（Ｈｓ）の測定結果を表３〜表６に示す。
Each cast iron material of Examples 1-4 and Comparative Examples 1-16 was cast so that it might become a component composition as shown in Table 1. Thereafter, heat treatment shown in FIG. 1 and Table 2 was performed for adjusting the base structure and hardness.
Tables 3 to 6 show the measurement results of hardness (Hs) of cast iron castings obtained by combinations of Examples 1 to 4 and Comparative Examples 1 to 16 and heat treatment patterns A to N.
前記実施例１〜４のうち、実施例３は成分組成がより好ましい範囲にあり、実施例２は成分組成が更に好ましい範囲にある。
前記比較例１〜１６は、何れも成分組成が本発明の成分組成には入っていない。
また熱処理パターンＡ〜Ｎのうち、Ｅ、Ｆ、Ｇ、Ｈ、Ｍ、Ｎは本発明の製造方法において用いる熱処理の条件に合致しているが、一方、Ａ、Ｂ、Ｃ、Ｄ、Ｉ、Ｊ、Ｋ、Ｌは本発明の製造方法において用いる熱処理の条件に合致していない。
表３〜表６において、実施例１〜４、比較例１〜１６で硬さを表記していないものは、一部変形が起こっているか、クラックが入っており、「×」と判定した。
Among Examples 1 to 4, Example 3 has a more preferable component composition, and Example 2 has a more preferable component composition.
In any of Comparative Examples 1 to 16, the component composition is not included in the component composition of the present invention.
Of the heat treatment patterns A to N, E, F, G, H, M, and N match the heat treatment conditions used in the production method of the present invention, while A, B, C, D, I, J, K, and L do not match the heat treatment conditions used in the production method of the present invention.
In Tables 3 to 6, in Examples 1 to 4 and Comparative Examples 1 to 16 where the hardness was not written, a part of the deformation occurred or a crack occurred and it was determined as “x”.
Claims (6)
Ｃ ：１．０〜２．５％、
Ｓｉ：０．２〜１．５％、
Ｍｎ：０．２〜１．５％、
Ｎｉ：０．５〜３．０％、
Ｃｒ：５．０〜９．０％、
Ｍｏ：０．８〜２．５％、
を含有し、残部がＦｅからなる成分組成を有し、
基地中に８０％以上のマルテンサイト相と２０％未満の残留オーステナイト相を含むと共に、金属炭化物が分散した組織からなり、且つ硬度が７４Ｈｓ以上であることを特徴とする鋳鉄鋳物。 % By weight
C: 1.0-2.5%
Si: 0.2 to 1.5%
Mn: 0.2 to 1.5%
Ni: 0.5 to 3.0%
Cr: 5.0-9.0%,
Mo: 0.8 to 2.5%,
And the balance has a component composition consisting of Fe,
A cast iron casting characterized in that the base contains a martensite phase of 80% or more and a residual austenite phase of less than 20%, has a structure in which metal carbide is dispersed, and has a hardness of 74Hs or more.
Ｃ ：１．２〜２．３％、
Ｓｉ：０．４〜１．３％、
Ｍｎ：０．４〜１．３％、
Ｎｉ：１．０〜２．５％、
Ｃｒ：５．５〜８．５％、
Ｍｏ：０．９〜２．４％、
を含有し、残部がＦｅからなる成分組成を有し、
基地中に８５％以上のマルテンサイト相と１５％未満の残留オーステナイト相を含むと共に、金属炭化物が分散した組織からなり、且つ硬度が７４〜８７Ｈｓであることを特徴とする請求項１に記載の鋳鉄鋳物。 % By weight
C: 1.2 to 2.3%
Si: 0.4 to 1.3%,
Mn: 0.4 to 1.3%
Ni: 1.0-2.5%,
Cr: 5.5 to 8.5%,
Mo: 0.9 to 2.4%,
And the balance has a component composition consisting of Fe,
2. The base according to claim 1, wherein the base includes a martensite phase of 85% or more and a residual austenite phase of less than 15%, is composed of a structure in which metal carbide is dispersed, and has a hardness of 74 to 87 Hs. Cast iron casting.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6254655B1 (en) * | 2016-09-15 | 2017-12-27 | 虹技株式会社 | Method for producing hypoeutectic spheroidal graphite cast iron castings |
| CN110527903A (en) * | 2019-07-22 | 2019-12-03 | 江苏润孚机械轧辊制造有限公司 | A kind of roll and preparation method thereof for galvanized aluminium board |
| CN111647793A (en) * | 2020-06-30 | 2020-09-11 | 广西大学 | Method for preparing nickel hard I-type cast iron by utilizing red mud to efficiently separate iron slag |
| CN112251579A (en) * | 2020-10-22 | 2021-01-22 | 安徽工业大学 | A method for reducing quenching retained austenite of pearlite-based gray cast iron |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6115938B2 (en) * | 1980-12-15 | 1986-04-26 | Kubota Ltd | |
| WO2013042528A1 (en) * | 2011-09-21 | 2013-03-28 | 日立金属株式会社 | Centrifugal casted composite roller for hot rolling and method for producing same |
| JP2013227598A (en) * | 2012-04-24 | 2013-11-07 | Kogi Corp | Iron casting and method for manufacturing the same |
-
2014
- 2014-04-14 JP JP2014082780A patent/JP6364219B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6115938B2 (en) * | 1980-12-15 | 1986-04-26 | Kubota Ltd | |
| WO2013042528A1 (en) * | 2011-09-21 | 2013-03-28 | 日立金属株式会社 | Centrifugal casted composite roller for hot rolling and method for producing same |
| JP2013227598A (en) * | 2012-04-24 | 2013-11-07 | Kogi Corp | Iron casting and method for manufacturing the same |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6254655B1 (en) * | 2016-09-15 | 2017-12-27 | 虹技株式会社 | Method for producing hypoeutectic spheroidal graphite cast iron castings |
| JP2018044216A (en) * | 2016-09-15 | 2018-03-22 | 虹技株式会社 | Method for producing hypoeutectic spheroidal graphite cast iron castings |
| CN110527903A (en) * | 2019-07-22 | 2019-12-03 | 江苏润孚机械轧辊制造有限公司 | A kind of roll and preparation method thereof for galvanized aluminium board |
| WO2021012692A1 (en) * | 2019-07-22 | 2021-01-28 | 江苏润孚机械轧辊制造有限公司 | Roller used for galvanized aluminium sheet and preparation method therefor |
| CN111647793A (en) * | 2020-06-30 | 2020-09-11 | 广西大学 | Method for preparing nickel hard I-type cast iron by utilizing red mud to efficiently separate iron slag |
| CN112251579A (en) * | 2020-10-22 | 2021-01-22 | 安徽工业大学 | A method for reducing quenching retained austenite of pearlite-based gray cast iron |
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