JPH0734132A - Production of high-strength and high-toughness bainite rail having excellent surface damage resistance - Google Patents
Production of high-strength and high-toughness bainite rail having excellent surface damage resistanceInfo
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- JPH0734132A JPH0734132A JP5181663A JP18166393A JPH0734132A JP H0734132 A JPH0734132 A JP H0734132A JP 5181663 A JP5181663 A JP 5181663A JP 18166393 A JP18166393 A JP 18166393A JP H0734132 A JPH0734132 A JP H0734132A
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、旅客鉄道の高速運転区
間で要求されるレール頭表面の耐表面損傷性に優れた高
強度・高靭性ベイナイト系レールの製造法に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-strength, high-toughness bainite rail having excellent surface damage resistance of the rail head surface required in a high-speed operation section of a passenger railway.
【０００２】[0002]
【従来の技術】近年、鉄道輸送の高効率化の手段とし
て、列車載荷重量の増加や列車運転速度の向上が図られ
ている。このような鉄道輸送の効率化はレール使用環境
の苛酷化を意味し、レール材質の一層の改善が要求され
るに至っている。具体的には、急曲線区間に敷設された
レールの摩耗が急激に増加し、また、レールと車輪の主
接触位置であるレールゲージ・コーナー（ＧＣ）部の内
部から発生する疲労損傷が頻発するようになり、この対
策として従来から下記に示す方法が採られてきた。 Ｃｒ，Ｍｏなどの合金元素を多量に添加した圧延まま
の合金鋼レール（特開昭５０−１４０３１６号公報）。 合金を添加せずに、レール頭部あるいは全体を加速冷
却することによって製造される熱処理レール（特開昭５
５−２３８８５号公報）。 比較的低い含有量の合金を添加して、耐摩耗性、耐損
傷性ばかりでなく、溶接部の硬度低下を改善した低合金
熱処理レール（特公昭５９−１９１７３号公報）。 これらレールの特徴は、高炭素の含有鋼による微細パー
ライト組織を呈する高強度レールであり、その目的とす
るところは耐摩耗性を向上させ、かつ、耐内部疲労損傷
抵抗性を改善させるところにあった。2. Description of the Related Art In recent years, as a means for improving the efficiency of rail transportation, an increase in on-vehicle load and an increase in train operating speed have been attempted. Such efficient rail transportation means that the rail usage environment becomes severe, and further improvement of rail materials has been demanded. Specifically, the wear of the rail laid in the sharp curve section sharply increases, and fatigue damage frequently occurs from inside the rail gauge corner (GC) which is the main contact position between the rail and the wheel. As a countermeasure against this, the following method has been conventionally adopted. An as-rolled alloy steel rail containing a large amount of alloy elements such as Cr and Mo (Japanese Patent Laid-Open No. 50-140316). Heat-treated rails manufactured by accelerating cooling of the rail head or the whole without adding an alloy (Japanese Patent Laid-Open Publication No. 5 (1999) -58242).
5-23885). A low alloy heat treatment rail (Japanese Patent Publication No. 59-19173) in which not only wear resistance and damage resistance but also a decrease in hardness of a welded portion is improved by adding an alloy having a relatively low content. The feature of these rails is that they are high-strength rails that exhibit a fine pearlite structure made of high carbon content steel, and their purpose is to improve wear resistance and internal fatigue damage resistance. It was
【０００３】一方、摩耗あるいは内部疲労損傷が問題と
ならない直線および緩曲線区間のレールにおいては、レ
ールと車輪の繰り返し接触に伴うころがり疲労損傷が発
生している。この代表的な損傷が新幹線などの高速鉄道
の主として直線区間のレールに生成する「頭頂面シェリ
ング」あるいは「ダークスポット損傷」と呼ばれるレー
ル頭頂面のき裂損傷である。このダークスポット損傷は
き裂の進展方向によってはレール横裂損傷を引き起こす
危険性があり、安全上問題視されている。しかし、上記
のような区間ではダークスポット損傷の発生が顕在化し
ているにもかかわらず、従来からのパーライト組織を呈
した圧延ままレールが使用されている。On the other hand, rolling fatigue damage occurs due to repeated contact between the rail and the wheel in rails in straight and gentle curve sections where wear or internal fatigue damage does not pose a problem. This typical damage is crack damage on the top surface of the rail called "crown surface shelling" or "dark spot damage" that is generated mainly on rails in straight sections of high-speed railways such as the Shinkansen. This dark spot damage may cause lateral rail crack damage depending on the crack propagation direction, and is considered a safety issue. However, although the occurrence of dark spot damage has become apparent in the above-mentioned section, a conventional as-rolled rail having a pearlite structure is used.
【０００４】主として旅客鉄道における直線あるいは緩
和曲線区間のレールには、ある特定期間（列車通過トン
数）経過後にレール頭表面を起点とするころがり疲労損
傷が生成する。本発明者らは上記損傷の発生原因を調査
した結果、この原因は、車輪とレールの繰り返し接触に
よってもたらされた疲労ダメージ層がレール頭表部に蓄
積するためであることを確認した。Rolling fatigue damage originating from the rail head surface is generated mainly on a rail in a straight line or a relaxation curve section of a passenger railway after a certain specific period (train passing tonnage). As a result of investigating the cause of the above-mentioned damage, the present inventors have confirmed that the cause is that a fatigue damage layer caused by repeated contact between the wheel and the rail accumulates on the rail head surface portion.
【０００５】この対策としては、定期的にレール頭表面
をグラインダーなどで研削する方法があるが、グライン
ディング車およびその作業費が高価である点や列車運転
間隔上研削時間が十分にとれないといった問題点があっ
た。また、もう一つの対策としてはレール頭表面の摩耗
速度を向上させ、疲労ダメージが蓄積する前に摩耗によ
りこの疲労層を除去する方法が考えられる。一般的には
レールの摩耗特性は硬さによって支配されており、摩耗
を促進させるためにはレールの硬さを低下させればよ
い。しかし、硬さを単純に低下させるとレール頭表部に
塑性変形が生成し、これに伴うき裂および剥離などのレ
ール頭表面損傷が多発するため、パーライト組織を呈す
る従来のレール鋼では上記損傷の発生を防止することが
困難であった。また、パーライト組織を呈した従来のレ
ール鋼は靭性が低いため、ころがり疲労損傷（ダークス
ポット損傷）が発生し、このき裂損傷が進展した場合に
は脆性破壊を引き起こしやすく、新幹線などの高速鉄道
ではレール横裂損傷による列車脱線事故が発生する危険
性があった。As a countermeasure for this, there is a method of periodically grinding the rail head surface with a grinder or the like, but the grinding car and its working cost are expensive, and the grinding time is not sufficient due to the train operation interval. There was a problem. As another countermeasure, a method of improving the wear rate of the rail head surface and removing this fatigue layer by wear before fatigue damage is accumulated can be considered. Generally, the wear characteristics of rails are governed by hardness, and the hardness of rails may be reduced to promote wear. However, if the hardness is simply reduced, plastic deformation is generated on the surface of the rail head, and as a result, rail surface damage such as cracks and peeling frequently occurs. It was difficult to prevent the occurrence of. In addition, since conventional rail steel with a pearlite structure has low toughness, rolling fatigue damage (dark spot damage) occurs, and if this crack damage progresses, brittle fracture is likely to occur, and high-speed railway such as Shinkansen There was a risk of train derailment accidents due to rail lateral crack damage.
【０００６】[0006]
【発明が解決しようとする課題】これまで、レール鋼と
して用いられてきたパーライト組織は、硬さの低いフェ
ライト組織と板状の硬いセメンタイト組織の層状組織で
あり、車輪の通過する軌道面では柔らかなフェライト組
織が絞り出され、硬いセメンタイトのみが積み重なり、
加工硬化が加わって耐摩耗性が確保されている。しか
し、同時に軌道面ではレール内部方向に層状の組織の流
れ（メタルフロー）が生成し、これに沿ってき裂損傷が
発生するという問題点があった。The pearlite structure that has been used as a rail steel has been a layered structure of a low hardness ferrite structure and a plate-like hard cementite structure, and is soft on the raceway surface through which the wheel passes. The ferrite structure is squeezed out, and only hard cementite is piled up,
Work hardening is added to ensure wear resistance. However, at the same time, on the track surface, a layered structure flow (metal flow) is generated inward of the rail, and crack damage occurs along the flow.
【０００７】一方、パーライト組織より摩耗量が大きい
ベイナイト組織では、柔らかなフェライト組織地に粒状
の微細なセメンタイトが分散した組織であるために、車
輪走行時にフェライト地と共にセメンタイトも摩耗によ
り簡単に摘み取られ、摩耗促進によってレール頭表部で
の疲労ダメージ層を除去させることが可能である。しか
し、合金量が少なく圧延ままで製造されるベイナイト鋼
は、フェライト地が大きく粒状のセメンタイトの分布も
粗いため、強度が低下する。このため車輪走行面直下の
レール頭表面に列車進行方向とは反対方向の連続した組
織の流れ（メタルフロー）が生成し、このフローに沿っ
てき裂損傷が発生するという問題点があった。また、フ
ェライト地が大きく粒状のセメンタイトの分布も粗いベ
イナイト鋼は、パーライト組織と比較して靭性が大きく
向上しないため、ころがり疲労損傷（ダークスポット損
傷）が発生し、このき裂損傷が進展した場合には脆性破
壊が発生しやすく、横裂損傷に対しては大きな改善効果
が期待できなかった。また、この問題点を解決する方法
として、Ｃｒ，Ｍｏなどの合金をさらに添加し、圧延ま
まで高強度で、かつ、高い靭性を有するベイナイト鋼を
製造することも可能である。しかし、高合金化は同時に
レール成分コストを大きく上昇させるという問題点があ
った。On the other hand, since the bainite structure, which has a larger wear amount than the pearlite structure, is a structure in which fine, granular cementite is dispersed in a soft ferrite structure, the cementite is easily scraped off by abrasion during wheel running. By promoting wear, it is possible to remove the fatigue damage layer at the rail head surface. However, the bainite steel produced with the small amount of alloy as it is rolled has a large ferritic material and a coarse distribution of granular cementite, so that the strength is lowered. Therefore, there is a problem in that a continuous tissue flow (metal flow) in the direction opposite to the train traveling direction is generated on the rail head surface immediately below the wheel traveling surface, and crack damage occurs along this flow. In addition, bainite steel with a large ferrite base and a coarse grained cementite distribution does not have much improved toughness compared to the pearlite structure, so rolling fatigue damage (dark spot damage) occurs and this crack damage develops. Since brittle fracture is apt to occur, a significant improvement effect on lateral crack damage could not be expected. Further, as a method for solving this problem, it is possible to further add an alloy such as Cr or Mo to produce bainite steel having high strength and high toughness as it is rolled. However, there is a problem that high alloying causes a large increase in rail component cost at the same time.
【０００８】そこで、本発明者らはこの問題を解決する
ために、熱間圧延した高温度の熱を保有するレール、あ
るいは熱処理する目的で高温に加熱されたレールの頭部
をオーステナイト域温度から冷却停止温度４００〜３０
０℃までの間を加速冷却し、加速冷却終了後レール頭部
をレール内部からの復熱による温度上昇を抑える冷却を
行うことにより、低合金で、かつ、高強度・高靭性のベ
イナイト系レールによりこの問題が解決できることを実
験により確認した。すなわち本発明は、上記製造プロセ
スを用いて、耐表面損傷性に優れた高強度・高靭性レー
ルを低コストで提供することを目的とするものである。Therefore, in order to solve this problem, the present inventors set the head of a hot-rolled rail holding high-temperature heat or a rail heated to a high temperature for the purpose of heat treatment from the austenite temperature range. Cooling stop temperature 400-30
Accelerated cooling up to 0 ° C, and after completion of accelerated cooling, the rail head is cooled to suppress the temperature rise due to reheat from the inside of the rail, so it is a low alloy, high strength, high toughness bainite rail. It was confirmed by experiment that this problem can be solved by. That is, an object of the present invention is to provide a high-strength / high-toughness rail excellent in surface damage resistance at low cost by using the above manufacturing process.
【０００９】[0009]
【課題を解決するための手段】本発明は上記目的を達成
するものであって、その要旨とするところは、重量％で
Ｃ ：０．１５〜０．４５％、 Ｓｉ：０．１５〜２．
００％、Ｍｎ：０．３０〜２．００％、 Ｃｒ：０．５
０〜３．００％を含有し、さらに必要によってはＭｏ：
０．１０〜０．６０％、 Ｃｕ：０．０５〜０．５０
％、Ｎｉ：０．０５〜４．００％、 Ｔｉ：０．０１〜
０．０５％、Ｖ ：０．０３〜０．３０％、 Ｎｂ：
０．０１〜０．０５％、Ｂ ：０．０００５〜０．００
５０％の一種または二種以上を含有し、残部が鉄および
不可避不純物からなる鋼を熱間圧延した高温度の熱を保
有するレール、あるいは熱処理する目的で高温に加熱さ
れたレールの頭部をオーステナイト域温度から冷却停止
温度４００〜３００℃までの間を１〜１０℃/secで加速
冷却し、加速冷却終了後レール頭部をレール内部からの
復熱による温度上昇を５０℃以下に抑える冷却を行い、
復熱による温度上昇終了後、引き続き低温度域まで自然
冷却する耐表面損傷性に優れた高強度・高靭性ベイナイ
ト系レールの製造法である。The present invention achieves the above objects, and the gist of the invention is as follows: C: 0.15 to 0.45% by weight%, Si: 0.15 to 2 ．
00%, Mn: 0.30 to 2.00%, Cr: 0.5
0 to 3.00%, and if necessary, Mo:
0.10 to 0.60%, Cu: 0.05 to 0.50
%, Ni: 0.05 to 4.00%, Ti: 0.01 to
0.05%, V: 0.03 to 0.30%, Nb:
0.01-0.05%, B: 0.0005-0.00
A rail containing 50% of one kind or two or more kinds, the balance of which is hot-rolled steel containing iron and unavoidable impurities, and the head of a rail heated to a high temperature for the purpose of heat treatment. Accelerated cooling at a temperature of 1 to 10 ° C / sec from the austenite temperature to the cooling stop temperature of 400 to 300 ° C, and cooling that suppresses the temperature rise of the rail head due to reheat from inside the rail to 50 ° C or less after the accelerated cooling is completed And then
This is a method for manufacturing bainite rails with high strength and high toughness, which have excellent surface damage resistance and continue to naturally cool to a low temperature range after the temperature rise due to recuperation.
【００１０】以下に本発明について詳細に説明する。ま
ず、レールの化学成分を上記のように定めた理由につい
て説明する。Ｃは一定の硬さを確保するための必須元素
であり、０．１５％未満ではレール鋼としての耐摩耗性
を確保することが難しくなり、０．４５％を超えると破
壊靭性が低く、表面損傷の発生に有害なパーライト組織
が多く生成することや、また、ベイナイト変態速度が大
きく低下し、加速冷却後の復熱冷却過程において完全に
ベイナイト変態を終了せずレールの靭性に有害なマルテ
ンサイト組織が生成するため、０．１５〜０．４５％に
限定した。The present invention will be described in detail below. First, the reason why the chemical composition of the rail is determined as described above will be described. C is an essential element for ensuring a certain hardness, and if it is less than 0.15%, it becomes difficult to secure the wear resistance as rail steel, and if it exceeds 0.45%, the fracture toughness is low and the surface Martensite, which is harmful to rail toughness, does not complete bainite transformation in the recuperative cooling process after accelerated cooling because a large amount of pearlite structure harmful to damage generation is generated and the bainite transformation rate is greatly reduced. Since the tissue is generated, the content is limited to 0.15 to 0.45%.
【００１１】Ｓｉはベイナイト組織中のフェライト素地
に固溶することによって強度を向上させる元素である
が、０．１５％以下では強度の向上が期待できない。ま
た、２．００％を超えるとレール圧延時に表面きずが発
生し易くなり、ベイナイト組織中に島状マルテンサイト
組織が生成し、レールの靭性を劣化させるため、０．１
５〜２．００％に限定した。Si is an element that improves the strength by forming a solid solution in the ferrite matrix in the bainite structure, but if the content is 0.15% or less, the improvement in the strength cannot be expected. Further, if it exceeds 2.00%, surface flaws are likely to occur during rail rolling, island martensite structure is generated in the bainite structure, and the toughness of the rail is deteriorated.
It was limited to 5 to 2.00%.
【００１２】ＭｎはＣ同様に鋼の焼入性を高めフェライ
ト粒を細かくし、強度と靭性を同時に向上させる効果を
持つが、０．３０％未満ではその効果が少なく、また、
２．００％を超えると、破壊靭性が低く、表面損傷の発
生に有害なパーライト組織が多く生成するため、０．３
０〜２．００％に限定した。Similar to C, Mn has the effect of enhancing the hardenability of steel and making the ferrite grains finer and simultaneously improving the strength and toughness, but if it is less than 0.30%, the effect is small, and
If it exceeds 2.00%, the fracture toughness is low and a large amount of pearlite structure, which is harmful to the occurrence of surface damage, is generated.
It was limited to 0 to 2.00%.
【００１３】Ｃｒはベイナイト組織中のセメンタイトを
微細に分散させ強度を確保するために重要な元素である
が、０．５０％未満ではベイナイト組織中のセメンタイ
トの分散が粗くなり、金属組織の塑性変形に伴う表面損
傷が発生する。また、３．００％以上では炭化物の粗大
化が生じるばかりか、ベイナイト変態速度が大きく低下
し、加速冷却後の復熱冷却過程において完全にベイナイ
ト変態を終了せずレールの靭性に有害なマルテンサイト
組織が生成するため、０．５０〜３．００％に限定し
た。Cr is an important element for finely dispersing the cementite in the bainite structure to secure the strength, but if it is less than 0.50%, the dispersion of the cementite in the bainite structure becomes coarse and the plastic deformation of the metal structure occurs. Surface damage caused by. Further, if it is 3.00% or more, not only coarsening of carbides occurs but also the bainite transformation rate significantly decreases, and bainite transformation is not completely completed in the recuperative cooling process after accelerated cooling, which is harmful to rail toughness martensite. Since it is generated by the tissue, it is limited to 0.50 to 3.00%.
【００１４】また、上記の成分組成で製造されるレール
は強度、延性、靭性、さらには溶接時の材料劣化を防止
する目的で以下の元素を必要に応じて一種または二種以
上を添加する。Ｍｏ：０．１０〜０．６０％、 Ｃ
ｕ：０．０５〜０．５０％、Ｎｉ：０．０５〜４．００
％、 Ｔｉ：０．０１〜０．０５％、Ｖ ：０．０３
〜０．３０％、 Ｎｂ：０．０１〜０．０５％、Ｂ
：０．０００５〜０．００５０％In addition, one or more of the following elements may be added to the rail manufactured with the above-mentioned component composition, if necessary, for the purpose of strength, ductility, toughness, and prevention of material deterioration during welding. Mo: 0.10 to 0.60%, C
u: 0.05 to 0.50%, Ni: 0.05 to 4.00
%, Ti: 0.01 to 0.05%, V: 0.03
~ 0.30%, Nb: 0.01-0.05%, B
: 0.0005 to 0.0050%
【００１５】次に、これらの化学成分を上記のように定
めた理由について説明する。ＭｏはＣｒ同様にベイナイ
ト組織の強化・安定、および溶接時の焼戻し脆化防止に
欠くことができない元素であるが、０．１０％未満では
その効果が十分でなく、０．６０％を超えるとベイナイ
ト変態速度が大きく低下し、加速冷却後の復熱冷却過程
において完全にベイナイト変態を終了せずレールの靭性
に有害なマルテンサイト組織が生成するため、０．１０
〜０．６０％に限定した。Ｃｕは鋼の靭性を損なわず強
度を向上させる元素である。その効果は０．０５〜０．
５０％の範囲で最も大きく、また、０．５０％を超える
と赤熱脆性を生じさせることから０．０５〜０．５０％
の範囲に限定した。Ｎｉはオーステナイト粒を安定化さ
せる元素であり、ベイナイト変態温度を下げ、ベイナイ
ト組織を微細化し、靭性を向上させる効果を有するが、
０．０５％未満ではその効果が著しく小さく、また、
４．００％を超える添加を行ってもその効果の向上が十
分に期待できないために０．０５〜４．００％の範囲に
限定した。Next, the reason for defining these chemical components as described above will be explained. Mo is an element that is indispensable for strengthening / stabilizing the bainite structure and preventing temper embrittlement during welding like Cr, but if it is less than 0.10%, its effect is not sufficient, and if it exceeds 0.60%. Since the bainite transformation rate is significantly reduced and the bainite transformation is not completely completed in the recuperative cooling process after accelerated cooling, a martensitic structure harmful to the toughness of the rail is generated.
Limited to ~ 0.60%. Cu is an element that improves the strength without impairing the toughness of steel. The effect is 0.05-0.
It is the largest in the range of 50%, and if it exceeds 0.50%, it causes red heat embrittlement, so it is 0.05 to 0.50%.
Limited to the range. Ni is an element that stabilizes austenite grains, and has the effects of lowering the bainite transformation temperature, refining the bainite structure, and improving the toughness,
If it is less than 0.05%, the effect is remarkably small.
Even if it is added in excess of 4.00%, the effect cannot be expected to be sufficiently improved, so the content was limited to the range of 0.05 to 4.00%.
【００１６】Ｔｉは析出したＴｉ（Ｃ，Ｎ）が高温でも
溶解しないことを利用して、レールの圧延加熱時のオー
ステナイト結晶粒の細粒化に寄与する。しかし、０．０
１％以下ではその効果が小さく、０．０５％以上ではＴ
ｉＮの粗大化が生じ、レール内部の疲労損傷の核となり
有害であり、０．０１〜０．０５％に限定した。Ｖは
（Ｃ，Ｎ）の析出によりベイナイト組織を強化すること
ができるが、０．０３％以下ではその効果が十分でな
く、０．３０％以上ではＶの添加はＶ（Ｃ，Ｎ）の粗大
化によりかえって脆化を生じさせるため、０．０３〜
０．３０％に限定した。Ｎｂはオーステナイト結晶粒微
細化元素であり、レール鋼の靭性および延性を向上させ
ることができるが、０．０１％以下ではその効果が十分
でなく、０．０５％以上ではＮｂの金属間化合物が生成
し脆化を引き起こすため、０．０１〜０．０５％に限定
した。Ｂはオーステナイト粒界から生成するフェライト
の生成を抑制する効果があり、ベイナイト組織を安定的
に生成させるためには有効な元素である。しかし、０．
０００５％以下ではその効果が弱く、０．００５０％以
上添加するとＢの粗大な化合物が生成し、レール材質を
劣化させるため０．０００５〜０．００５０％に限定し
た。By utilizing the fact that the precipitated Ti (C, N) does not dissolve even at high temperatures, Ti contributes to the refinement of austenite crystal grains during rolling and heating of the rail. But 0.0
If less than 1%, the effect is small, and if more than 0.05%, T
The iN is coarsened and becomes a nucleus of fatigue damage inside the rail, which is harmful and is limited to 0.01 to 0.05%. V can strengthen the bainite structure by precipitation of (C, N), but if 0.03% or less, the effect is not sufficient, and if 0.30% or more, V is added to V (C, N). Since coarsening rather causes embrittlement, 0.03 to
It was limited to 0.30%. Nb is an austenite grain refinement element and can improve the toughness and ductility of the rail steel, but if it is 0.01% or less, its effect is not sufficient, and if it is 0.05% or more, the intermetallic compound of Nb is present. Since it is generated and causes embrittlement, it is limited to 0.01 to 0.05%. B has an effect of suppressing the generation of ferrite generated from austenite grain boundaries, and is an effective element for stably generating a bainite structure. However, 0.
The effect is weak at 0005% or less, and if 0.0050% or more is added, a coarse compound of B is formed and the rail material is deteriorated, so the content is limited to 0.0005 to 0.0050%.
【００１７】上記のような成分組成で構成されるレール
鋼は、転炉、電気炉などの通常使用される溶解炉で溶製
を行い、この溶鋼を造塊・分塊法あるいは連続鋳造法、
さらに熱間圧延を経てレールとして製造される。次に、
冷却条件について前記のように定めた理由について説明
する。前記のような成分組成で構成されるレールは、転
炉、電気炉などの通常使用される溶解炉で溶製を行い、
造塊・分塊あるいは連続鋳造法によりレール圧延用素材
を製造し、次に、熱間圧延した高温度の熱を保有するレ
ール、あるいは熱処理する目的で高温に加熱されたレー
ルの頭部をオーステナイト域温度から冷却停止温度４０
０〜３００℃までの間を１〜１０℃/secで加速冷却し、
加速冷却終了後レール頭部をレール内部からの復熱によ
る温度上昇を５０℃以下に抑える冷却を行って製造され
るレールは、まず、加速冷却することにより、低温度域
でベイナイト変態を開始させ、その後の復熱による温度
上昇を抑えることにより、高強度で、かつ、高い靭性を
有するベイナイト組織を安定的に成長させることが可能
となる。The rail steel composed of the above-described composition is melted in a commonly used melting furnace such as a converter or an electric furnace, and the molten steel is ingot-segmented or continuously cast,
Further, it is manufactured as a rail through hot rolling. next,
The reason for setting the cooling conditions as described above will be described. Rails composed of the above component composition are melted in a commonly used melting furnace such as a converter or an electric furnace.
A rail rolling material is manufactured by ingot-casting, slab-casting, or continuous casting, and then hot-rolled rails that retain high-temperature heat or heads of rails that have been heated to a high temperature for the purpose of heat treatment are austenite. Cooling temperature 40 from region temperature
Accelerated cooling at 0 ~ 300 ℃ at 1 ~ 10 ℃ / sec,
After completion of the accelerated cooling, the rail manufactured by cooling the rail head to suppress the temperature rise due to the heat recovery from the inside of the rail to 50 ° C or less first starts accelerated bainite transformation in the low temperature range by accelerated cooling. By suppressing the temperature rise due to the subsequent heat recovery, it becomes possible to stably grow a bainite structure having high strength and high toughness.
【００１８】各加速冷却速度、冷却停止温度範囲および
復熱による温度上昇を上記のように定めた理由を詳細に
説明する。まず、冷却停止温度までの加速冷却速度を１
〜１０℃/secの範囲に限定した理由について説明する。
上記成分系において１℃/sec以下で冷却すると、冷却途
中の高温度域でベイナイト変態が始まり、粗大なベイナ
イト組織が生成する。このためレールの強度・靭性が低
下するため１℃/sec以上に限定した。また、１０℃/sec
以上で冷却すると、その後の復熱冷却領域において、レ
ール内部からの復熱量が大きく、復熱による温度上昇を
抑える冷却が困難となり、温度上昇が５０℃以上になる
場合がある。このためベイナイト組織が粗大化し、レー
ルの強度・靭性が低下するため１０℃/sec以下に限定し
た。The reason why each accelerated cooling rate, cooling stop temperature range and temperature rise due to recuperation are determined as described above will be described in detail. First, set the accelerated cooling rate up to the cooling stop temperature to 1
The reason why the range is limited to 10 ° C / sec will be described.
When cooling is performed at 1 ° C./sec or less in the above component system, bainite transformation starts in a high temperature region during cooling and a coarse bainite structure is generated. For this reason, the strength and toughness of the rail are reduced, so the limit is set to 1 ° C / sec or more. Also, 10 ° C / sec
When the cooling is performed as described above, the amount of reheat from the inside of the rail is large in the subsequent reheat cooling region, cooling that suppresses the temperature rise due to the reheat becomes difficult, and the temperature rise may reach 50 ° C. or more. For this reason, the bainite structure becomes coarse and the strength and toughness of the rail deteriorate, so the content is limited to 10 ° C / sec or less.
【００１９】次に、オーステナイト域温度からの加速冷
却停止温度を４００〜３００℃の範囲に限定した理由に
ついて説明する。本成分系において４００℃以上で冷却
を停止すると、引き続く復熱冷却領域でベイナイト組織
が粗大化しやすく、レールの強度および靭性が低下する
ため４００℃以下に限定した。また、３００℃以下まで
冷却すると、ベイナイト組織中に硬いマルテンサイト組
織が生成し、さらに、その後の復熱冷却領域においてレ
ール内部からの復熱が十分に得られず、硬いマルテンサ
イト組織が多く残留する。このためレールの靭性が著し
く低下するため３００℃以上に限定した。Next, the reason why the accelerated cooling stop temperature from the austenite temperature is limited to the range of 400 to 300 ° C. will be described. When cooling is stopped at 400 ° C. or higher in this component system, the bainite structure is likely to coarsen in the subsequent recuperative cooling region, and the strength and toughness of the rail are reduced, so the temperature was limited to 400 ° C. or lower. Further, when cooled to 300 ° C. or less, a hard martensite structure is generated in the bainite structure, and further, the reheat from the inside of the rail cannot be sufficiently obtained in the subsequent reheat cooling region, and a large amount of the hard martensite structure remains. To do. For this reason, the toughness of the rail is significantly reduced, so the temperature is limited to 300 ° C or higher.
【００２０】最後に、復熱による温度上昇を５０℃以下
に限定した理由について説明する。本成分系レールの頭
部をオーステナイト域温度から１〜１０℃/secで加速冷
却し、４００〜３００℃の温度範囲で加速冷却を停止し
た場合、レール頭部において最高１００℃の自然復熱に
よる温度上昇が実験により確認されている。しかし、本
冷却停止温度範囲で１００℃程度の温度上昇が発生する
と、ベイナイト鋼の強度を確保することは可能である
が、復熱により一部の組織が粗大化するため靭性が低下
する。そこで、本成分系レールの頭部をオーステナイト
域温度から１〜１０℃/secで加速冷却し、４００〜３０
０℃の温度範囲で加速冷却を停止し、さらに加速冷却停
止後レール頭部をレール内部からの復熱を抑える冷却実
験を行った結果、本加速冷却速度範囲および加速冷却停
止温度範囲においては、レール内部からの復熱を５０℃
以下に抑えることでベイナイト組織の粗大化を防止し、
高強度で、かつ、高い靭性を有したベイナイト組織が生
成することを確認した。この結果から、本発明では復熱
による温度上昇を５０℃以下に限定した。なお、この復
熱冷却領域においては、復熱温度０〜５０℃の範囲での
恒温変態的な温度変化や不規則な温度変化も含んでい
る。すなわち、本発明においてオーステナイト域温度か
ら１〜１０℃/secで加速冷却し、加速冷却停止温度を４
００〜３００℃の範囲にすることによって、低温度域で
ベイナイト変態を開始させ、さらに、復熱による温度上
昇を抑えることにより、高強度で、かつ、高い靭性を有
するベイナイト組織を安定的に成長させることが可能と
なる。Finally, the reason why the temperature rise due to recuperation is limited to 50 ° C. or less will be described. When the head of this component system rail is accelerated cooled from the austenite region temperature at 1 to 10 ° C / sec and the accelerated cooling is stopped in the temperature range of 400 to 300 ° C, natural reheat of up to 100 ° C occurs at the rail head. The temperature rise has been confirmed by experiments. However, if a temperature rise of about 100 ° C. occurs in the main cooling stop temperature range, it is possible to secure the strength of the bainite steel, but part of the structure becomes coarse due to recuperation, so the toughness decreases. Therefore, the head of this component system rail is accelerated cooled at a temperature of 1 to 10 ° C / sec from the temperature of the austenite region to 400 to 30
As a result of performing a cooling experiment in which accelerated cooling is stopped in the temperature range of 0 ° C., and after the accelerated cooling is stopped, the rail head is restrained from recuperating heat from the inside of the rail, as a result, in the accelerated cooling speed range and the accelerated cooling stop temperature range, 50 ℃ reheat from inside the rail
Preventing the bainite structure from coarsening by suppressing below,
It was confirmed that a bainite structure with high strength and high toughness was generated. From this result, in the present invention, the temperature rise due to recuperation is limited to 50 ° C or less. In the recuperation cooling region, there are constant temperature transformation-like temperature changes and irregular temperature changes in the recuperation temperature range of 0 to 50 ° C. That is, in the present invention, accelerated cooling is performed at a temperature of 1 to 10 ° C./sec from the austenite region temperature, and the accelerated cooling stop temperature is set to 4
By setting the temperature in the range of 00 to 300 ° C., bainite transformation is started in the low temperature range, and by suppressing the temperature rise due to recuperation, a bainite structure having high strength and high toughness is stably grown. It becomes possible.
【００２１】なお、成分系および加速冷却速度の選択に
よっては加速冷却途中の４００〜３００℃の冷却停止温
度範囲においてベイナイト変態が開始し、その後の復熱
冷却領域で変態を完了する場合と、加速冷却直後の復熱
冷却領域においてベイナイト変態が開始し、変態を完了
する場合がある。しかし、本冷却停止温度範囲において
はいずれのベイナイト組織も耐表面損傷性に優れ、か
つ、高強度・高靭性であるため、本発明のベイナイト組
織としては、加速冷却途中の４００〜３００℃の冷却停
止温度範囲において生成するベイナイト組織と加速冷却
後の復熱冷却領域において生成するベイナイト組織の両
方を含んでいる。Depending on the selection of the component system and the accelerated cooling rate, the bainite transformation starts in the cooling stop temperature range of 400 to 300 ° C. during the accelerated cooling and the transformation is completed in the subsequent recuperative cooling region, and the accelerated cooling is performed. In the reheat cooling region immediately after cooling, bainite transformation may start and the transformation may be completed. However, in the main cooling stop temperature range, any bainite structure is excellent in surface damage resistance, and has high strength and high toughness. Therefore, as the bainite structure of the present invention, cooling at 400 to 300 ° C. during accelerated cooling is performed. Both the bainite structure formed in the stop temperature range and the bainite structure formed in the recuperative cooling region after accelerated cooling are included.
【００２２】また、この冷却後の金属組織はベイナイト
組織であることが望ましいが、加速冷却速度および冷却
停止温度の選択によってはベイナイト組織中に微小なマ
ルテンサイト組織が混入し、最終的にはレール内部の復
熱により焼戻しマルテンサイト組織として存在すること
がある。しかし、ベイナイト組織中に微小な焼戻しマル
テンサイト組織が混入してもレールの耐表面損傷性、強
度、靭性に大きな影響をおよぼさないため、本ベイナイ
ト系レールの組織としては若干の焼戻しマルテンサイト
組織の混在も含んでいる。Although the metal structure after cooling is preferably a bainite structure, a fine martensite structure is mixed in the bainite structure depending on the selection of the accelerated cooling rate and the cooling stop temperature, and finally the rail structure. It may exist as a tempered martensite structure due to internal heat recovery. However, even if a minute tempered martensite structure is mixed in the bainite structure, it does not significantly affect the surface damage resistance, strength, and toughness of the rail. It also includes mixed organizations.
【００２３】加速冷却・復熱冷却時の冷却媒体としては
空気あるいはミストなどの気液混合物を用いる。また、
加速冷却・復熱冷却後のレール頭部の強度、靭性につい
ては、引張強さ：１１００MPa 、吸収エネルギー：０．
５０MJ/m2 （ＪＩＳ３号２mmＵノッチ試験片）以上とす
ることが望ましい。上記のような本発明法によって製造
されたベイナイト系レールは、高速旅客鉄道用の高強度
レールとして要求される耐表面損傷性および靭性を有し
ている。A gas-liquid mixture such as air or mist is used as a cooling medium at the time of accelerated cooling / recuperation cooling. Also,
Regarding the strength and toughness of the rail head after accelerated cooling / recuperation cooling, tensile strength: 1100 MPa, absorbed energy: 0.
It is desirable to set it to 50 MJ / m 2 (JIS No. 2 mm U notch test piece) or more. The bainite rail manufactured by the method of the present invention as described above has the surface damage resistance and toughness required as a high-strength rail for high-speed passenger rail.
【００２４】[0024]
【実施例】次に、本発明の実施例について説明する。表
１に、本発明レールと比較レールの化学成分および冷却
条件を示す。表２に本発明レールと比較レールの硬さ、
西原式摩耗試験における乾燥条件下での５０万回繰り返
し後の摩耗量測定結果およびレールおよび車輪の形状を
１／４に縮尺加工した円盤試験片による水潤滑ころがり
疲労試験の表面損傷発生寿命を示す。また、本発明レー
ルと比較レールの落重試験結果を表３に示す。なお、表
２にはレール頭部から採取した試験片を用いて衝撃試験
を行った結果（吸収エネルギ−値）も併記した。EXAMPLES Next, examples of the present invention will be described. Table 1 shows the chemical components and cooling conditions of the rail of the present invention and the comparative rail. Table 2 shows the hardness of the present invention rail and the comparative rail,
The results of measuring the amount of wear after repeated 500,000 times under dry conditions in the Nishihara-type wear test and the surface damage occurrence life of a water-lubricated rolling fatigue test using a disk test piece with the rail and wheel shapes scaled to 1/4 are shown. . Table 3 shows the results of the drop weight test of the rail of the present invention and the comparative rail. Table 2 also shows the results (absorbed energy value) of an impact test using a test piece taken from the rail head.
【００２５】なお、レールの構成材料の組織は以下のと
おりである。 ・本発明レール（１０本） 符号Ａ、符号Ｂ、符号Ｃ、符号Ｄ、符号Ｅ、符号Ｆ、符
号Ｇ、符号Ｈ、符号Ｉ、符号Ｊ：レール頭部を加速冷却
し、その後復熱による温度上昇を抑える冷却を行うこと
によって製造されるベイナイト系レール ・比較レール（３本） 符号Ｋ：圧延後自然放冷されたベイナイト系レール 符号Ｌ：レール頭部を加速冷却し、その後自然冷却され
ることによって製造されるベイナイト系レール 符号Ｍ：圧延後自然放冷されたパーライト組織を呈する
レールThe structure of the rail constituent material is as follows. -Invention rail (10 pieces) Code A, code B, code C, code D, code E, code F, code G, code H, code I, code J: Accelerated cooling of the rail head, and then reheating Bainite rail manufactured by cooling to suppress temperature rise ・ Comparative rails (3 pieces) Code K: Bainite rail that is naturally cooled after rolling Code L: Accelerated cooling of the rail head, and then natural cooling Bainite-type rail manufactured by the method: Code M: Rail exhibiting a pearlite structure that is naturally cooled after rolling
【００２６】また試験条件は次のとおりとした。 摩耗試験条件（全試験レール共通） ・試験機 ：西原式摩耗試験機 ・試験片形状：円盤状試験片（外径：３０mm、厚さ：８
mm） ・試験荷重 ：４９０Ｎ ・すべり率 ：９％ ・相手材 ：焼戻しマルテンサイト鋼（Ｈｖ３５０） ・雰囲気 ：大気中 ・繰返し回数：５０万回The test conditions were as follows. Abrasion test conditions (common to all test rails) -Testing machine: Nishihara-type abrasion tester-Test piece shape: Disc-shaped test piece (outer diameter: 30 mm, thickness: 8)
mm) ・ Test load: 490N ・ Slip ratio: 9% ・ Mating material: Tempered martensitic steel (Hv350) ・ Atmosphere: In air ・ Number of repetitions: 500,000 times
【００２７】ころがり疲労試験 ・試験機 ：ころがり疲労試験機 ・試験片形状：円盤状試験片（外径：２００mm、レール
材断面形状：６０Ｋレールの１／４モデル） ・試験荷重 ：１．５トン（ラジアル荷重） ・雰囲気 ：乾燥＋水潤滑（６０cc/min） ・回転数 ：乾燥；１００rpm 、水潤滑；３００rpm ・繰返し回数：０〜５０００回まで乾燥状態、その後水
潤滑により損傷発生まで実施Rolling Fatigue Test ・ Testing Machine: Rolling Fatigue Testing Machine ・ Shape of test piece: Disc-shaped test piece (outer diameter: 200 mm, rail material cross-sectional shape: 60K rail 1/4 model) ・ Test load: 1.5 tons (Radial load) -Atmosphere: Drying + water lubrication (60cc / min) -Rotational speed: Drying; 100 rpm, water lubrication; 300 rpm-Number of repetitions: 0 to 5000 times in a dry state, then water lubrication until damage occurs
【００２８】落重試験条件（全試験片とも共通） ・試験機 ：落重試験機 ・試験片長さ ：１．３ｍ ・支点間の距離：１．０ｍ ・支持方法 ：頭部を下にして試験する（底部に落錘
を落とす） ・落錘の重さ ：１０００kg ・落錘の高さ ：１０ｍ ・試験温度 ：０〜−１１０℃Drop weight test conditions (common to all test pieces) -Testing machine: Dropping weight tester-Test piece length: 1.3 m-Distance between fulcrums: 1.0 m-Supporting method: Test with head down Do (drop the falling weight on the bottom) -Weight of falling weight: 1000 kg-Height of falling weight: 10 m-Test temperature: 0 to -110 ° C
【００２９】[0029]
【表１】 [Table 1]
【００３０】[0030]
【表２】 [Table 2]
【００３１】[0031]
【表３】 [Table 3]
【００３２】表２で明らかなように、本発明レールＡ，
Ｂ，Ｃ，Ｄ，Ｅ、および、Ｆ，Ｇ，Ｈ，Ｉ，Ｊは、従来
のパーライト組織を呈するレールＭと比較して、摩耗量
が多く、ころがり疲労損傷発生寿命が大きく改善する。
また、圧延ままのベイナイト系レールＫおよび圧延後レ
ール頭部を加速冷却し、その後自然冷却されることによ
って製造されるベイナイト系レールＬと比較してもころ
がり疲労損傷発生寿命が大きく改善する。また、表３に
本発明レールと比較レールの落重試験結果を示す。各試
験条件ともに、レール４本中の落重試験後の破断の有無
について表中に示した。As is clear from Table 2, the rails A of the present invention,
B, C, D, E, and F, G, H, I, J have a large amount of wear and a significantly improved rolling fatigue damage occurrence life, as compared with the rail M having a conventional pearlite structure.
Further, compared with the bainite rail L manufactured by subjecting the as-rolled bainite rail K and the rail head after rolling to accelerated cooling and then natural cooling, the rolling fatigue damage occurrence life is greatly improved. Table 3 shows the results of the drop weight test of the rail of the present invention and the comparative rail. For each test condition, the presence or absence of breakage in the four rails after the drop weight test is shown in the table.
【００３３】比較レールが−３０〜−５０℃で４本全て
のレールが破断してしまうのに対して、本発明レール
は、−９０℃まで４本全てのレールが破断しないことが
明らかになった。While all four rails of the comparative rail were broken at -30 to -50 ° C, it was revealed that all of the four rails of the invention rail were not broken up to -90 ° C. It was
【００３４】[0034]
【発明の効果】このように本発明によれば、従来レール
と比較して耐表面損傷性およびレール頭部の破壊靭性も
明らかに向上している高強度・高靭性ベイナイト系レー
ルが得られる。As described above, according to the present invention, a high strength / high toughness bainite rail having a surface damage resistance and a fracture toughness of a rail head which are obviously improved as compared with a conventional rail can be obtained.
Claims (2)
熱間圧延した高温度の熱を保有するレール、あるいは熱
処理する目的で高温に加熱されたレールの頭部をオース
テナイト域温度から冷却停止温度４００〜３００℃まで
の間を１〜１０℃/secで加速冷却し、加速冷却終了後レ
ール頭部を、レール内部からの復熱による温度上昇を５
０℃以下に抑える冷却を行い、復熱による温度上昇終了
後、引き続き低温度域まで自然冷却することを特徴とす
る耐表面損傷性に優れた高強度・高靭性ベイナイト系レ
ールの製造法。1. C: 0.15 to 0.45% by weight, Si: 0.15 to 2.00%, Mn: 0.30 to 2.00%, Cr: 0.50 to 3.00 %, With the balance being iron and unavoidable impurities, and hot-rolled steel that holds high-temperature heat, or the rail head that has been heated to a high temperature for the purpose of heat treatment, stops cooling from the austenite region temperature. Accelerated cooling at a temperature of 400 to 300 ° C at 1 to 10 ° C / sec. After the accelerated cooling, the temperature of the rail head is increased by the heat recovery from the inside of the rail.
A method for producing a high-strength, high-toughness bainite rail having excellent surface damage resistance, which comprises cooling to 0 ° C. or lower, and then naturally cooling to a low temperature range after the temperature rise due to recuperation is completed.
不純物からなる鋼を熱間圧延した高温度の熱を保有する
レール、あるいは熱処理する目的で高温に加熱されたレ
ールの頭部をオーステナイト域温度から冷却停止温度４
００〜３００℃までの間を１〜１０℃/secで加速冷却
し、加速冷却終了後レール頭部を、レール内部からの復
熱による温度上昇を５０℃以下に抑える冷却を行い、復
熱による温度上昇終了後、引き続き低温度域まで自然冷
却することを特徴とする耐表面損傷性に優れた高強度・
高靭性ベイナイト系レールの製造法。2. C: 0.15 to 0.45% by weight%, Si: 0.15 to 2.00%, Mn: 0.30 to 2.00%, Cr: 0.50 to 3.00 %, Further, Mo: 0.10 to 0.60%, Cu: 0.05 to 0.50%, Ni: 0.05 to 4.00%, Ti: 0.01 to 0.05% , V: 0.03 to 0.30%, Nb: 0.01 to 0.05%, B: 0.0005 to 0.0050%, and the balance contains iron and unavoidable impurities. Of the high temperature heat-rolled rail of hot-rolled steel or the head of the rail heated to high temperature for heat treatment from the austenite region temperature to the cooling stop temperature 4
Accelerated cooling from 0 to 300 ° C at 1 to 10 ° C / sec. After completion of accelerated cooling, the rail head is cooled to suppress the temperature rise due to recuperation from inside the rail to 50 ° C or less, High strength with excellent surface damage resistance characterized by natural cooling to a low temperature range after the temperature rise is finished.
High toughness bainite rail manufacturing method.
Priority Applications (14)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18166393A JP2912123B2 (en) | 1993-07-22 | 1993-07-22 | Manufacturing method of high-strength and high-toughness bainite-based rail with excellent surface damage resistance |
| AU56304/94A AU663023B2 (en) | 1993-02-26 | 1994-02-22 | Process for manufacturing high-strength bainitic steel rails with excellent rolling-contact fatigue resistance |
| EP01102992A EP1101828B1 (en) | 1993-02-26 | 1994-02-23 | High-strength bainitic steel rails with excellent rolling-contact fatigue resistance |
| DE69429685T DE69429685T2 (en) | 1993-02-26 | 1994-02-23 | Process for producing high-strength bainitic steel rails with improved resistance to fatigue damage due to rolling contact |
| DE69433512T DE69433512T2 (en) | 1993-02-26 | 1994-02-23 | High-strength bainitic steel rails with improved resistance to fatigue damage due to rolling contact |
| EP94102721A EP0612852B1 (en) | 1993-02-26 | 1994-02-23 | Process for manufacturing high-strength bainitic steel rails with excellent rolling-contact fatique resistance |
| AT94102721T ATE212384T1 (en) | 1993-02-26 | 1994-02-23 | METHOD FOR PRODUCING HIGH STRENGTH BAINITIC STEEL RAILS WITH IMPROVED RESISTANCE TO FATIGUE DAMAGE DUE TO ROLLING CONTACT |
| AT01102992T ATE258232T1 (en) | 1993-02-26 | 1994-02-23 | HIGH-STRENGTH BAINITIC STEEL RAILS WITH IMPROVED RESISTANCE TO FATIGUE DAMAGE DUE TO ROLLING CONTACT |
| US08/201,924 US5382307A (en) | 1993-02-26 | 1994-02-24 | Process for manufacturing high-strength bainitic steel rails with excellent rolling-contact fatigue resistance |
| KR1019940003310A KR0131437B1 (en) | 1993-02-26 | 1994-02-24 | Process for manufacturing high-strength bainitic steel rails with excellent rolling contact fatigue resistance |
| BR9400689A BR9400689A (en) | 1993-02-26 | 1994-02-25 | Process for the production of high-strength bainitic steel rails and high-strength bainitic steel rail |
| CN94101720A CN1040660C (en) | 1993-02-26 | 1994-02-25 | Manufacture of bainite steel rail with high strength and good performence of anti-rolling-endurance-failure |
| RU9494006015A RU2086671C1 (en) | 1993-02-26 | 1994-02-25 | Method of manufacturing high-strength rail (versions) and high- strength rail |
| CA002116504A CA2116504C (en) | 1993-02-26 | 1994-02-25 | Process for manufacturing high-strength bainitic steel rails with excellent rolling-contact fatigue resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18166393A JP2912123B2 (en) | 1993-07-22 | 1993-07-22 | Manufacturing method of high-strength and high-toughness bainite-based rail with excellent surface damage resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0734132A true JPH0734132A (en) | 1995-02-03 |
| JP2912123B2 JP2912123B2 (en) | 1999-06-28 |
Family
ID=16104697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18166393A Expired - Lifetime JP2912123B2 (en) | 1993-02-26 | 1993-07-22 | Manufacturing method of high-strength and high-toughness bainite-based rail with excellent surface damage resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2912123B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10195604A (en) * | 1996-12-19 | 1998-07-28 | Voest Alpine Schienen Gmbh | Specially formed rolling material and its production |
| EP0834885A3 (en) * | 1996-10-02 | 1998-11-18 | Nitto Chemical Industry Co., Ltd. | Method for producing soluble conductive polymers having acidic groups |
| WO1999036583A1 (en) * | 1998-01-14 | 1999-07-22 | Nippon Steel Corporation | Bainite type rail excellent in surface fatigue damage resistance and wear resistance |
| JP2007146237A (en) * | 2005-11-28 | 2007-06-14 | Nippon Steel Corp | Heat-treatment method for bainite steel rail |
| JP2011529137A (en) * | 2008-07-24 | 2011-12-01 | シーアールエス ホールディングス，インコーポレイテッド | High strength and high toughness steel alloy |
| CN103429766A (en) * | 2011-05-30 | 2013-12-04 | 塔塔钢铁有限公司 | Bainitic steel of high strength and high elongation and method to manufacture said bainitic steel |
-
1993
- 1993-07-22 JP JP18166393A patent/JP2912123B2/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0834885A3 (en) * | 1996-10-02 | 1998-11-18 | Nitto Chemical Industry Co., Ltd. | Method for producing soluble conductive polymers having acidic groups |
| JPH10195604A (en) * | 1996-12-19 | 1998-07-28 | Voest Alpine Schienen Gmbh | Specially formed rolling material and its production |
| WO1999036583A1 (en) * | 1998-01-14 | 1999-07-22 | Nippon Steel Corporation | Bainite type rail excellent in surface fatigue damage resistance and wear resistance |
| US6254696B1 (en) | 1998-01-14 | 2001-07-03 | Nippon Steel Corporation | Bainitic type rail excellent in surface fatigue damage resistance and wear resistance |
| JP2007146237A (en) * | 2005-11-28 | 2007-06-14 | Nippon Steel Corp | Heat-treatment method for bainite steel rail |
| JP4644105B2 (en) * | 2005-11-28 | 2011-03-02 | 新日本製鐵株式会社 | Heat treatment method for bainite steel rail |
| JP2011529137A (en) * | 2008-07-24 | 2011-12-01 | シーアールエス ホールディングス，インコーポレイテッド | High strength and high toughness steel alloy |
| CN103429766A (en) * | 2011-05-30 | 2013-12-04 | 塔塔钢铁有限公司 | Bainitic steel of high strength and high elongation and method to manufacture said bainitic steel |
| CN103429766B (en) * | 2011-05-30 | 2015-08-05 | 塔塔钢铁有限公司 | There is the bainitic steel of high strength and high-elongation and manufacture the method for described bainitic steel |
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| Publication number | Publication date |
|---|---|
| JP2912123B2 (en) | 1999-06-28 |
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