JPH01159326A - Manufacture of high-strength rail with weldability - Google Patents
Manufacture of high-strength rail with weldabilityInfo
- Publication number
- JPH01159326A JPH01159326A JP31708587A JP31708587A JPH01159326A JP H01159326 A JPH01159326 A JP H01159326A JP 31708587 A JP31708587 A JP 31708587A JP 31708587 A JP31708587 A JP 31708587A JP H01159326 A JPH01159326 A JP H01159326A
- Authority
- JP
- Japan
- Prior art keywords
- rail
- cooling
- weldability
- hardness
- steel
- 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
Links
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 7
- 238000001816 cooling Methods 0.000 claims abstract description 29
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 23
- 239000010959 steel Substances 0.000 claims abstract description 23
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 16
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 8
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 6
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 5
- 238000005098 hot rolling Methods 0.000 claims abstract description 5
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 239000000203 mixture Substances 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 4
- 229910052758 niobium Inorganic materials 0.000 abstract description 4
- 229910052799 carbon Inorganic materials 0.000 abstract description 3
- 238000003466 welding Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 229910001562 pearlite Inorganic materials 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000010953 base metal Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000009826 distribution Methods 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- 230000009466 transformation Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 229910001567 cementite Inorganic materials 0.000 description 2
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 101150050712 CRK gene Proteins 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000009916 joint effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000004881 precipitation hardening Methods 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
Landscapes
- Heat Treatment Of Articles (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、海外の重荷重鉱山鉄道のような苛酷な条件下
で耐摩耗性が必須要件となるレールに適用されるもので
はなく、国内の旅客鉄道のような比較的軽荷重条件下で
使用され溶接性が重要視される高強度レールの製造法に
関するものである。[Detailed Description of the Invention] [Field of Industrial Application] The present invention is not applied to rails where wear resistance is an essential requirement under severe conditions such as heavy-load mining railways overseas, but This invention relates to a method for manufacturing high-strength rails that are used under relatively light load conditions, such as passenger railways, and where weldability is important.
比較的軽荷重の旅客鉄道においても、急曲線区間に敷設
された曲線外軌レールでは普通炭素鋼を用いた場合には
、耐摩耗性が問題となる。Even in passenger railways with relatively light loads, wear resistance becomes a problem when ordinary carbon steel is used for curved outer gauge rails installed in sharply curved sections.
また、曲線内戦レールにおいても普通炭素鋼では波状摩
耗が生成して、しばしば問題となっている。さらに国内
の旅客鉄道においては、市街地を走るために急曲線区間
が多く、曲線部のきしみ音を防止するために塗油が施さ
れている。Furthermore, even in curved internal rails, ordinary carbon steel often produces wavy wear, which often poses a problem. Furthermore, since domestic passenger railways run through urban areas, there are many sections with sharp curves, and the trains are oiled to prevent squeaks at the curves.
塗油の効果としてレールの摩耗が抑制される反面、疲労
ダメージのレール頭表面への蓄積により表面損傷が発生
したり、レール内部からの疲労破壊が発生したりする。Although the effect of oiling is to suppress rail wear, it also causes surface damage due to accumulation of fatigue damage on the rail head surface, and fatigue failure from within the rail.
これらの耐摩耗性や耐疲労損傷性に加えて、レールの品
質特性として近年の鉄道では、溶接性が重要な特性とな
りてきている。レール溶接によってロングレール化する
ことで、レール損傷の中で大きな部分を占める端部破壊
を防止し軌道保守の合理化が果たせるばかりか、レール
継目部による騒音・振動を低減することができる。この
ような溶接性に対する要求に対応して、強度が１３０
Ｋｐｆ／−前後の高強度レールが開発されている。特開
昭５５−１２５２３１号公報はｒｃ：ｏ、５５〜０．８
０チ、Ｓｔ：０．５〜１．２０チ。In addition to wear resistance and fatigue damage resistance, weldability has become an important rail quality characteristic for railways in recent years. By creating long rails through rail welding, we can not only prevent end breakage, which accounts for the majority of rail damage, and streamline track maintenance, but also reduce noise and vibration caused by rail joints. In response to such requirements for weldability, the strength is 130.
High strength rails around Kpf/- have been developed. JP-A No. 55-125231 has rc:o, 55-0.8
0chi, St: 0.5-1.20chi.
Ｍｎ ： ０．８０〜１．５０ ｓ、 Ａ！ ： ０．
００５〜０．０５ ％、あるいは更にＣｒ ： ０．２
０〜０．９０ ’Ａｔ Ｎｂ ： ０．００４〜０．０
１０％を含有する溶接性低合金鋼熱処理レール」であり
、特開昭６２−５６５２４号公報はｒｃ：ｏ、ｓｓ〜０
．８５俤、Ｓｔ：０．２０〜１．２０チ。Mn: 0.80~1.50s, A! : 0.
005-0.05%, or even Cr: 0.2
0~0.90'AtNb: 0.004~0.0
Weldable low alloy steel heat treated rail containing 10% rc:o, ss~0 in JP-A-62-56524
．． 85 yen, St: 0.20-1.20 yen.
Ｍｎ ： ０．５〜１．６５％、 Ｃｒ ： ０．１〜
０．１９％、あるいはこれにＮｂ、Ｖ、Ｔｉを一種以上
含有する溶接性を付与した高強度レール」などがあるが
、これらはいずれも溶接熱影響部が狭いフラッシュバッ
ト溶接法を用いたものである。Mn: 0.5~1.65%, Cr: 0.1~
0.19% or more of Nb, V, and Ti to give weldability. All of these are made using the flash butt welding method, which has a narrow heat-affected zone. It is.
しかしながら、国内の旅客鉄道における溶接法の主流は
ガス圧接法であり、フラッシュバット溶接法に比べて格
段に熱影響部が広い。前記した特開昭５５−１２５２３
１の高強度レールの場合には、母材部の硬度に比べて溶
接継手部の硬度が極端に低下する。また、特開昭６２−
５６５２４の中間高強度レールの母材部に対しても、ガ
ス圧接では入熱量が大きいためにやはり溶接継手部の硬
度低下が生じ、母材部と継手部の硬度一体化が図れず釦
、継手部の摩耗によって列車通過時に騒音・振動の原因
となる。However, the mainstream welding method used in domestic passenger railways is gas pressure welding, which has a much wider heat affected zone than flash butt welding. JP-A-55-12523 mentioned above
In the case of the high-strength rail No. 1, the hardness of the welded joint is extremely lower than that of the base metal. Also, JP-A-62-
56524 intermediate high-strength rail, the hardness of the welded joint also decreases due to the large amount of heat input in gas pressure welding, and the hardness of the base metal and joint cannot be unified, resulting in hardness of the button and joint. Wear on the parts causes noise and vibration when trains pass.
本発明はレール圧延終了後のオーステナイト域からの冷
却において、８００〜４５０℃間を１〜ｂ
ス圧接継手部の硬度であるＨＢ ２８０〜３２０に相当
する母材熱処理硬度を得ることを特徴としている。その
要旨は、Ｃ：０．５５〜０．８５チ、 Ｓｉ： ０．２
０〜１．２０ Ｓｔ Ｍｎ ： ０．５０〜１．５０％
、Ｃｒ：０．２０〜０．５０％、 Ｂ ： ０．０００
３〜０．００３０％。The present invention is characterized by obtaining a base metal heat treatment hardness corresponding to HB 280 to 320, which is the hardness of the pressure welded joint, at 800 to 450°C during cooling from the austenite region after rail rolling. . The gist is: C: 0.55-0.85chi, Si: 0.2
0-1.20 St Mn: 0.50-1.50%
, Cr: 0.20-0.50%, B: 0.000
3-0.0030%.
あるいは更にＮｂ：０．０１〜０．０５チ、Ｖ：０．０
５〜０．２０％、Ｔｉ：０．０１〜０．０５ ｔＩ６の
一種または二種以上を含有し、残部が鉄および不可避的
不純物からなる鋼を、レール熱間圧延後のオーステナイ
ト域からの冷却において、８００〜４５０℃間を１〜ｂ
とする溶接性付与高強度レールの製造法である。Or further Nb: 0.01 to 0.05, V: 0.0
5 to 0.20%, Ti: 0.01 to 0.05 A steel containing one or more of tI6 and the remainder consisting of iron and inevitable impurities is cooled from the austenite region after rail hot rolling. This is a method for producing a high-strength rail with weldability in which the temperature is 1 to b between 800 and 450°C.
以下に本発明について詳細に説明する。 The present invention will be explained in detail below.
本発明は転炉あるいは電気炉で溶製した下記成分範囲の
レール鋼を用いる。The present invention uses rail steel melted in a converter or electric furnace and having the following composition range.
ｌ Ｃ：０．５５〜０．８５％、ｓｔ：ｏ、ｚｏ〜１
．２０％Ｍｎ ： ０．５０〜１．５０％、 Ｃｒ ：
０．２０〜０．５０’４Ｂ：０．０００３〜０．００
３０チ。lC:0.55~0.85%, st:o, zo~1
．． 20%Mn: 0.50-1.50%, Cr:
0.20-0.50'4B: 0.0003-0.00
30 chi.
を含有し残部が鉄および不可避的不純物からなる鋼。steel with the balance consisting of iron and unavoidable impurities.
Ｉ Ｃ：０．５５〜０．８５％、Ｓｉ：０．２０〜１
．２０％Ｍｎ ： ０．５０〜１．５０％、 Ｏｒ ：
０．２０〜０．５０％Ｂ：０．０００３〜０．００３
０俤。IC: 0.55-0.85%, Si: 0.20-1
．． 20%Mn: 0.50-1.50%, Or:
0.20-0.50% B: 0.0003-0.003
0 yen.
ヲ含有シ、Ｎｂ ： ０．０１〜０．０５ ％、 Ｖ
： ０．０５〜０．２０チ、Ｔｉ：０．０１〜０．０５
俤の−１または二種以上を含有し、残部が鉄および不可
避的不純物からなる鋼。Contains Nb: 0.01-0.05%, V
: 0.05 to 0.20 Ti, Ti: 0.01 to 0.05
A steel containing one or more of the following: -1 or more, with the remainder consisting of iron and unavoidable impurities.
これらの化学成分のうち、
Ｃは高強度化およびパーライト組織生成のための必須元
素であり、また耐−粍性に対して一義的に効果を示す元
素であるが、０．５５％未満ではオーステナイト粒界に
耐摩耗性、耐疲労損傷性に好ましくない初析フェライト
が多量に生成し、０．８５％を越えるとオーステナイト
粒界に脆弱な初析セメンタイトを生成させるばかりか、
レール頭部内部の微小偏析部にマルテンサイト組織が生
成して脆化を促すため０．５５〜０．８５俤に限定した
。Ｓｉはパーライト組織中のフェライト地に固溶するこ
とによって強度を上昇させ耐摩耗性を向上させる元素で
あるが、脱酸元素としても０．２０ ’１６以上の添加
が必要であり、また１、 ２０ ’１６を超えると脆化
が生じ靭性を損なうため０．２０〜１．２０％に限定し
た。Among these chemical components, C is an essential element for high strength and pearlite structure formation, and is an element that has a unique effect on corrosion resistance, but if it is less than 0.55%, it will cause austenite formation. A large amount of pro-eutectoid ferrite, which is unfavorable for wear resistance and fatigue damage resistance, is generated at the grain boundaries, and if it exceeds 0.85%, it not only causes the formation of brittle pro-eutectoid cementite at the austenite grain boundaries.
The thickness was limited to 0.55 to 0.85 because a martensitic structure is generated in minute segregation inside the rail head and promotes embrittlement. Si is an element that increases strength and improves wear resistance by solidly dissolving in the ferrite base in the pearlite structure, but it also needs to be added in an amount of 0.20'16 or more as a deoxidizing element. If it exceeds 20'16, embrittlement occurs and toughness is impaired, so it is limited to 0.20 to 1.20%.
ＭｎはＣ同様にパーライト変態温度を低下させ焼入性を
高めることによって、高強度化に寄与する元素である。Like C, Mn is an element that contributes to high strength by lowering the pearlite transformation temperature and increasing hardenability.
しかし、Ｏ，ＳＯ％以下ではその寄与が小さくまた１、
５０ ％を超えるとレール頭部内部の微小偏析部やガ
ス圧接継手部にマルチ／ティトを生成させやすくするた
め０．５０〜１．５０俤に限定した。However, below O,SO%, its contribution is small and 1,
If it exceeds 50%, it will be easy to generate multi/tito in micro-segregation parts inside the rail head and gas pressure joints, so it is limited to 0.50 to 1.50.
Ｃｒはパーライト変態開始温度を低下させることにより
て高強度化に寄与するばかりか、パーライト中のセメン
タイトを強化することによっても耐摩耗性の向上に貢献
することが見出されており、熱処理レールのガス圧接継
手部の硬度低下防止に対しても欠くべからざる元素であ
る。It has been found that Cr not only contributes to higher strength by lowering the pearlite transformation start temperature, but also contributes to improving wear resistance by strengthening the cementite in pearlite, and is effective for heat-treated rails. It is also an indispensable element for preventing a decrease in the hardness of gas pressure joints.
Ｃｒは０．２０ ％以下ではガス圧接継手部の硬度増加
が期待できず０．５０％以上のＣｒの添加では、ガス圧
接継手部の硬度が母材部の硬度より高くなって一体硬度
が得られないことからＣｒ添加量を０．２〜０．５チに
限定した。If Cr is less than 0.20%, no increase in the hardness of the gas pressure welded joint can be expected; if Cr is added in excess of 0.50%, the hardness of the gas pressure welded joint becomes higher than the hardness of the base material, resulting in an increase in the hardness of the gas pressure welded joint. Therefore, the amount of Cr added was limited to 0.2 to 0.5.
Ｂは初析７エライトの生成を抑制する元素として良く知
られており、パーライト組織の生成に対してもオーステ
ナイト粒界の微小なフェライト核の生成抑制を通して高
強度化に寄与する。B is well known as an element that suppresses the formation of pro-eutectoid hepterythrite, and also contributes to increasing strength by suppressing the formation of minute ferrite nuclei at austenite grain boundaries, even against the formation of a pearlite structure.
従って、ガス圧接継手部の軟化防止に効果的である。Ｂ
の０． ＯＯＯ３％以下ではこの効果がほとんど認めら
れず、また０、 ００３０１以上では粗大なり化合物が
生成し上記効果を打ち消すばかりか、かえって靭性を劣
化させることから上限を０．００３０チとした。Therefore, it is effective in preventing softening of the gas pressure joint. B
0. If OOO is less than 3%, this effect is hardly observed, and if it is more than 0.00301, coarse compounds are formed, which not only negates the above effect but also deteriorates the toughness, so the upper limit was set at 0.0030.
さらに本発明においては、上記成分の他に必要に応じて
Ｎｂ、Ｖ、Ｔｉなどの元素を添加することができる。こ
れらの元素はオーステナイト粒の細粒化元素であるが、
Ｎｂはガス圧接継手部のような１２５０℃以上の高温加
熱時には、Ｎｂ析出物が完全に溶解するときオーステナ
イト粒界成長抑制効果を失って、かえってオーステナイ
ト粒を粗大化させることが知られている。従って、 Ｎ
ｂの添加によってガス圧接継手部の焼入性をたかめ、継
手部の高硬度化に寄与する。このとき有効なＮｂ添加量
は０．０１ ％であり、０．０５俤を超えると粗大なＮ
ｂＣが生成しかえって靭性低下を招く。従ってＮｂの成
分範囲を０．０１〜０．０５％に限定した。ＶはＮｂよ
り低温で溶解し、Ｎｂのようなオーステナイト粒の粗粒
化効果はないが、冷却中に再析出したＶ（Ｃ，Ｎ）によ
る析出硬化で強度増加が期待できる。しかし、ｖｆ）ｏ
、ｏｓｓ以下の添刀口ではその析出物の数も少なく所定
の硬化は期待できない。また、０，２０チを超えるＶの
添加は￥（Ｃ，Ｎ）の粗大化によりてかえって脆化が生
ずる。このためＶの成分範囲を０．０５〜０．２０ ｆ
ａ Ｋ限定した。Ｔｉは凝固時に析出したＴｉＮが高温
でも溶融しないことが知られており、通常のレール圧延
加熱温度でもオーステナイトの初期粒度を細粒化する目
的のためには有効であり、母材部とガス圧接継手部の靭
性改善のために活用することができる。しかし、Ｔｉも
Ｎｂ同様ＫＯ，０１１以下ではその効果はほとんど認め
られず、０．０５％を超えるとＴｉＮの粗大化が生じて
レール内部損傷の起点となる可能性が高いため、Ｔｉの
成分範囲を０．０１〜０．０５％に限定した。Furthermore, in the present invention, in addition to the above-mentioned components, elements such as Nb, V, and Ti may be added as necessary. These elements are austenite grain refining elements,
It is known that when Nb is heated at a high temperature of 1250° C. or higher, such as in gas pressure welding joints, when Nb precipitates are completely dissolved, it loses its effect of suppressing austenite grain boundary growth, and instead coarsens austenite grains. Therefore, N
The addition of b increases the hardenability of the gas pressure welded joint and contributes to increasing the hardness of the joint. At this time, the effective amount of Nb added is 0.01%, and if it exceeds 0.05, coarse Nb will be added.
bC is generated instead, leading to a decrease in toughness. Therefore, the Nb component range was limited to 0.01 to 0.05%. Although V melts at a lower temperature than Nb and does not have the effect of coarsening austenite grains like Nb, an increase in strength can be expected due to precipitation hardening due to V (C, N) reprecipitated during cooling. However, vf)o
, oss or less, the number of precipitates is small and the desired hardening cannot be expected. Furthermore, adding more than 0.20 inches of V will cause embrittlement due to the coarsening of C,N. Therefore, the component range of V is set to 0.05 to 0.20 f
a K limited. It is known that TiN that precipitates during solidification does not melt even at high temperatures, and is effective for refining the initial grain size of austenite even at normal rail rolling heating temperatures. It can be used to improve the toughness of joints. However, like Nb, Ti has almost no effect below KO,011, and when it exceeds 0.05%, TiN becomes coarse and is likely to become the starting point for internal damage to the rail. was limited to 0.01-0.05%.
この他、本発明において不可避的不純物成分としてＰ、
Ｓは本発明の目的を阻害する有害な成分であり、極力低
下せしめる必要がある。In addition, in the present invention, unavoidable impurity components include P,
S is a harmful component that obstructs the purpose of the present invention, and it is necessary to reduce it as much as possible.
次に本発明では、上記の化学組成を有するレール鋼を熱
間圧延後のオーステナイト域からの冷却において、８０
０〜４５０℃間を冷却速度１〜４℃／ｓ！ｃで加速冷却
する。この熱処理条件の詳細を以下に説明する。Next, in the present invention, in cooling the rail steel having the above chemical composition from the austenite region after hot rolling, 80%
Cooling rate 1-4℃/s between 0-450℃! Accelerate cooling at c. The details of the heat treatment conditions will be explained below.
本発明において８００〜４５０℃を設定したのは、便宜
的に冷却速度を規定するためのものであり、冷却範囲を
規定したものではない。The setting of 800 to 450° C. in the present invention is for convenience in defining the cooling rate, and does not define the cooling range.
８００℃はレール圧延後の十分なオーステナイト域を示
すもので、また４５０℃はパーライト変態の終了に十分
な温度であり、８００〜４５０℃間はレール頭表面のパ
ーライト変態発熱を含んでいる。冷却速度の下限を１℃
／（６）としたのは、これ以下の速度ではガス圧接継手
部の下限硬度）１８２８０以上に相当する母材硬度が得
られないからである。また、４℃／（６）以上の冷却速
度では母材硬度が高硬度化してしまい、摩耗がほぼ完全
に抑制される結果、レール頭表面に疲労ダメージが蓄積
して表面損傷を生成させる。800°C indicates a sufficient austenite region after rail rolling, and 450°C is a temperature sufficient to complete pearlite transformation, and the temperature between 800 and 450°C includes the heat generated by pearlite transformation on the rail head surface. Lower limit of cooling rate to 1℃
/(6) is because if the speed is lower than this, the base material hardness corresponding to the lower limit hardness of the gas pressure joint part) of 18280 or more cannot be obtained. Further, at a cooling rate of 4° C./(6) or more, the base material hardness increases, and wear is almost completely suppressed, resulting in accumulation of fatigue damage on the rail head surface and generation of surface damage.
以上の理由から、８００〜４５０℃間の冷却速度を１〜
ｂ
なお、これらの加速冷却方法として圧縮空気冷却、気水
冷却、水冷、湯冷、流動層冷却、およびこれらの組み合
わせのいずれでも可能であり、熱間圧延後に引き続いて
加速冷却処理を行う。For the above reasons, the cooling rate between 800 and 450℃ is
b Note that any of these accelerated cooling methods can be compressed air cooling, air/water cooling, water cooling, hot water cooling, fluidized bed cooling, or a combination thereof, and the accelerated cooling treatment is performed successively after hot rolling.
次に本発明の実施例について説明する。 Next, examples of the present invention will be described.
第１表に本発明鋼と比較鋼の化学成分を示した。Table 1 shows the chemical components of the invention steel and comparative steel.
表１ 本発明鋼と比較鋼の化学成分
表２に本発明鋼と比較鋼の冷却速度とガス圧接継手部の
硬度を示す。Table 1 Chemical composition of inventive steel and comparative steel Table 2 shows the cooling rate and hardness of the gas pressure welded joint of the inventive steel and comparative steel.
表２本発明鋼と比較鋼の冷却速度とガス圧接継手部の硬
度Ｍ１図は本発明鋼と比較鋼の上記化学成分レールの冷
却後母材硬度とガス圧接継手部の硬度分布を示す。Table 2 Cooling rate and hardness of gas pressure welded joint of inventive steel and comparative steel M1 Figure shows the base metal hardness after cooling of the chemical composition rail of the invention steel and comparative steel and the hardness distribution of the gas pressure welded joint.
本発明鋼Ａは比較的緩曲線に使用される中間的な高強度
を得るための代表的な化学成分と、そのガス圧接継手部
の硬度分布である。本発明鋼Ｂは急曲線区間に使用され
る高強度レールで、本発明の熱処理により母材部と継手
部の硬度分布に一体化が達成されている。このように本
発明では、レール圧延終了後のオーステナイト域からの
熱処理によって任意に強度を造り分けることができる。The steel A of the present invention has a typical chemical composition and hardness distribution of the gas pressure welded joint part to obtain intermediate high strength used for relatively gentle curves. Steel B of the present invention is a high-strength rail used in sharply curved sections, and the heat treatment of the present invention achieves an integrated hardness distribution in the base material and the joint. As described above, in the present invention, the strength can be arbitrarily determined by heat treatment from the austenite region after rail rolling.
これに対して、従来の再加熱熱処理では強度の低い熱処
理レールを製造するために、高強度の場合と同じ熱量で
加熱しゆっくり冷却せねばならず、かえって生産性を落
とし余計なコストをかけねば製造できない。On the other hand, in conventional reheating heat treatment, in order to manufacture a heat-treated rail with low strength, it must be heated with the same amount of heat and cooled slowly as in the case of high strength, which reduces productivity and requires additional costs. Cannot be manufactured.
比較鋼ＣはＣｒｋｏ、５％以上含有する低合金熱処理レ
ールであるが、母材硬度に比べて継手部の硬度が低く、
高強度熱処理レールではガス圧接部との硬度の一体化が
図れない。たとえ、母材部熱処理時に冷却速度を制御し
たとしてもガス圧接継手部の硬度レベルが高すぎて、継
手部に疲労損傷が発生する。一方、比較鋼りではガス圧
接部の硬度が低過ぎて継手特性が劣る結果となる。Comparative steel C is a low-alloy heat-treated rail containing 5% or more of Crko, but the hardness of the joint part is lower than the hardness of the base material.
High-strength heat-treated rails cannot have the same hardness as the gas pressure welding part. Even if the cooling rate is controlled during the heat treatment of the base metal, the hardness level of the gas pressure joint will be too high and fatigue damage will occur in the joint. On the other hand, in the comparison steel, the hardness of the gas pressure welded part was too low, resulting in inferior joint properties.
第１図は本発明鋼と比較鋼のガス圧接継手部のレール長
手方向の断面硬度分布図である。FIG. 1 is a cross-sectional hardness distribution diagram in the rail longitudinal direction of the gas pressure welding joint of the steel of the present invention and the comparative steel.
Claims (1)
レール熱間圧延後のオーステナイト域からの冷却におい
て、８００〜４５０℃間を１〜４℃／ｓｅｃで加速冷却
することを特徴とする溶接性付与高強度レールの製造法
。 ２ 重量％で Ｃ：０．５５〜０．８５％ Ｓｉ：０．２０〜１．２０％ Ｍｎ：０．５０〜１．５０％ Ｃｒ：０．２０〜０．５０％ Ｂ：０．０００３〜０．００３０％ 更にＮｂ：０．０１〜０．０５％、Ｖ：０．０５〜０．
２０％、Ｔｉ：０．０１〜０．０５％の一種または二種
以上 を含有し、残部が鉄および不可避的不純物からなる鋼を
、レール熱間圧延後のオーステナイト域からの冷却にお
いて、８００〜４５０℃間を１〜４℃／ｓｅｃで加速冷
却することを特徴とする溶接性付与高強度レールの製造
法。[Claims] 1% by weight: C: 0.55-0.85% Si: 0.20-1.20% Mn: 0.50-1.50% Cr: 0.20-0.50% Steel containing B: 0.0003 to 0.0030% with the balance consisting of iron and inevitable impurities,
A method for producing a high-strength rail with weldability, characterized in that in cooling from the austenite region after hot rolling of the rail, accelerated cooling is performed at a rate of 1 to 4°C/sec between 800 and 450°C. 2% by weight C: 0.55-0.85% Si: 0.20-1.20% Mn: 0.50-1.50% Cr: 0.20-0.50% B: 0.0003- 0.0030%, further Nb: 0.01-0.05%, V: 0.05-0.
20%, Ti: 0.01 to 0.05%, and the remainder is iron and inevitable impurities. A method for producing a high-strength rail with weldability, characterized by accelerated cooling between 450°C and a rate of 1 to 4°C/sec.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31708587A JPH01159326A (en) | 1987-12-15 | 1987-12-15 | Manufacture of high-strength rail with weldability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31708587A JPH01159326A (en) | 1987-12-15 | 1987-12-15 | Manufacture of high-strength rail with weldability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01159326A true JPH01159326A (en) | 1989-06-22 |
Family
ID=18084259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31708587A Pending JPH01159326A (en) | 1987-12-15 | 1987-12-15 | Manufacture of high-strength rail with weldability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01159326A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02133544A (en) * | 1988-11-14 | 1990-05-22 | Nkk Corp | Rail steel stock excellent in quenching crack resistance |
| JP2010090456A (en) * | 2008-10-10 | 2010-04-22 | Nippon Steel & Sumikin Stainless Steel Corp | Joint of stainless steel reinforcing bar having superior corrosion resistance |
| JP2015158006A (en) * | 2014-01-21 | 2015-09-03 | 新日鐵住金株式会社 | Pearlite rail and production method thereof |
-
1987
- 1987-12-15 JP JP31708587A patent/JPH01159326A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02133544A (en) * | 1988-11-14 | 1990-05-22 | Nkk Corp | Rail steel stock excellent in quenching crack resistance |
| JP2010090456A (en) * | 2008-10-10 | 2010-04-22 | Nippon Steel & Sumikin Stainless Steel Corp | Joint of stainless steel reinforcing bar having superior corrosion resistance |
| JP2015158006A (en) * | 2014-01-21 | 2015-09-03 | 新日鐵住金株式会社 | Pearlite rail and production method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPS6323244B2 (en) | ||
| JPS629646B2 (en) | ||
| JPH09316598A (en) | Pearlitic rail, excellent in wear resistance and weldability, and its production | |
| JPH0730401B2 (en) | Method for producing high strength rail with excellent toughness | |
| JPH08246100A (en) | Pearlitic rail excellent in wear resistance and its production | |
| JP4344073B2 (en) | High strength steel excellent in high temperature strength and method for producing the same | |
| JP4264177B2 (en) | Method for producing a steel material having a coarse ferrite layer on the surface layer | |
| JP2004084068A (en) | Non-haettreated low yield ratio high tensile strength steel having excellent high temperature strength and production method therefor | |
| JPS613842A (en) | Manufacture of high strength rail | |
| JP3267772B2 (en) | Manufacturing method of high strength, high ductility, high toughness rail | |
| JPH0248608B2 (en) | ||
| JP4153650B2 (en) | Manufacturing method of high weldability rail | |
| JPH01159326A (en) | Manufacture of high-strength rail with weldability | |
| JPS6256523A (en) | Manufacture of high strength rail providing weldability | |
| JPH01159327A (en) | Manufacture of rail having high strength and high toughness | |
| JPH1192866A (en) | Bainitic steel rail excellent in joinability in weld zone, and its production | |
| JP2001152291A (en) | Bainitic rail excellent in resistance to rolling fatigue damage and internal fatigue damage and welded joint properties, and its manufacturing method | |
| JP4061141B2 (en) | Perlite high-strength rail excellent in ductility and manufacturing method thereof | |
| JP3117915B2 (en) | Manufacturing method of high wear resistant pearlite rail | |
| JPH0138853B2 (en) | ||
| JP3327065B2 (en) | Method for producing tempered high-strength steel sheet excellent in brittle crack propagation arrestability | |
| JPS6369918A (en) | Manufacture of high strength rail having superior toughness | |
| KR20200061920A (en) | Hot-rolled steel sheet for oil pipe with excellent heat treatment characteristics and method for manufacturing the same | |
| KR910003883B1 (en) | Making process for high tension steel | |
| JPH09295067A (en) | Manufacture of high strength bent pipe excellent in toughness at welded metal part |