JPS6364499B2 - - Google Patents
Info
- Publication number
- JPS6364499B2 JPS6364499B2 JP9215781A JP9215781A JPS6364499B2 JP S6364499 B2 JPS6364499 B2 JP S6364499B2 JP 9215781 A JP9215781 A JP 9215781A JP 9215781 A JP9215781 A JP 9215781A JP S6364499 B2 JPS6364499 B2 JP S6364499B2
- Authority
- JP
- Japan
- Prior art keywords
- cooling
- welding
- rail
- welded
- pressure
- 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.)
- Expired
Links
- 238000001816 cooling Methods 0.000 claims description 48
- 238000000034 method Methods 0.000 claims description 42
- 229910001562 pearlite Inorganic materials 0.000 claims description 13
- 239000000110 cooling liquid Substances 0.000 claims description 10
- 238000005304 joining Methods 0.000 claims description 8
- 239000010409 thin film Substances 0.000 claims description 7
- 229910001566 austenite Inorganic materials 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 2
- 230000001131 transforming effect Effects 0.000 claims description 2
- 238000003466 welding Methods 0.000 description 49
- 238000010791 quenching Methods 0.000 description 10
- 239000007789 gas Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 6
- 230000000171 quenching effect Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 238000005496 tempering Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000005275 alloying Methods 0.000 description 4
- 229910000734 martensite Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000003832 thermite Substances 0.000 description 4
- 230000009466 transformation Effects 0.000 description 4
- 238000009826 distribution Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000003303 reheating Methods 0.000 description 2
- 238000004904 shortening Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000010002 mechanical finishing Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
- C21D9/505—Cooling thereof
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Pressure Welding/Diffusion-Bonding (AREA)
- Heat Treatment Of Articles (AREA)
Description
【発明の詳細な説明】
本発明は、熱処理レールの接合方法の改良に関
するものであつて、具体的には熱処理レールの溶
接による場合に、従来避けることのできなかつた
軟化部の発生を防止することを目的とするもので
ある。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for joining heat-treated rails, and specifically, in the case of welding heat-treated rails, it is possible to prevent the occurrence of softened parts that could not be avoided in the past. The purpose is to
近年、鉄道輸送は高軸重化、高速化を志向しつ
つあり、そのためレールの使用条件は苛酷になる
傾向がある。その結果レール頭部の摩耗や疲労が
激しく、レール寿命は短くなり、保守作業にも支
障を来すのでレール頭部の高強度化が要求されて
いる。 In recent years, rail transportation has been moving toward higher axle loads and higher speeds, and as a result, the conditions for using rails have tended to become harsher. As a result, the rail head is subject to severe wear and fatigue, shortening the rail life and complicating maintenance work, so there is a demand for higher strength rail heads.
一般に、レール頭部の材質を改善するには次の
方法が知られている。 Generally, the following methods are known for improving the material of the rail head.
(イ) 合金元素を添加し、熱間圧延状態にて高強度
化を図る。(a) Adding alloying elements to increase the strength in the hot rolled state.
(ロ) 熱間圧延後再加熱熱処理を施して高強度化を
図る。(b) After hot rolling, perform reheating heat treatment to increase strength.
然るに、前記(イ)の方法は、合金元素添加による
コスト・アツプのみでなく、合金元素添加によつ
て水素割れ感受性が増大するため脱水素処理等の
製造工程を付加する必要を生じ、これがまたコス
トを高くすることになり、経済的に有利な方法で
はない。前記(ロ)の方法は、レール頭部の硬化法と
して適していて、次の２つの熱処理方法が採られ
ている。 However, the method (a) described above not only increases costs due to the addition of alloying elements, but also requires additional manufacturing steps such as dehydrogenation treatment because the addition of alloying elements increases hydrogen cracking susceptibility. This increases the cost and is not an economically advantageous method. The method (b) above is suitable as a method for hardening the rail head, and the following two heat treatment methods are adopted.
(a) 焼入―焼戻し法
(b) スラツク・クエンチ法による焼入れ法
しかしながら、前記(a)の方法によれば、たしか
にレール頭部より約５mmの深さまで硬化させるこ
とはできるが、焼戻しマルテンサイトを主体とす
る組織を呈し、大きな耐摩耗性向上は左程期待で
きない。又、前記(b)の方法は、近年、前記(a)法に
代つて採用されつつある方法であつて、炭素鋼レ
ール成分の鋼を熱間圧延後、火炎又は高周波によ
りAc3点以上に再加熱し、圧縮空気又は噴霧又は
水による加速冷却を施すことにより、低温域にて
パーライト変態を生じさせるものであつて、緻密
なパーライト組織を具備した耐摩耗性の大なる高
強度レールが得られることで知られている。(a) Quenching-tempering method (b) Quenching method using slack quench method However, according to method (a) above, it is certainly possible to harden the rail to a depth of about 5 mm, but the tempered martensite It exhibits a structure mainly consisting of , and no significant improvement in wear resistance can be expected. In addition, method (b) above is a method that has recently been adopted as an alternative to method (a) above, and is a method in which carbon steel rail component steel is heated to Ac 3 points or higher using flame or high frequency after hot rolling. By reheating and accelerating cooling with compressed air, spray, or water, pearlite transformation occurs in a low temperature range, and a high-strength rail with high wear resistance and a dense pearlite structure can be obtained. It is known for being
一方、昔から行われているレール継目部を継目
板とそれを緊締する結合方法は、破損防止や乗心
地の改善、騒音防止等の対策が必要であり、その
一環として溶接によるロングレー化も進められて
おり、レールの溶接が不可欠となりつつある。レ
ールの溶接法としては、フラツシユバツト溶接
法、ガス圧接法、テルミツト溶接法およびエンク
ローズドアーク溶接法などが挙げられるが、これ
らのうちフラツシユバツト圧接法、ガス圧接法の
２法が基地溶接に、テルミツト溶接法、エンクロ
ーズドアーク溶接法が現地溶接に採用されてい
る。後者のテルミツト溶接法およびエンクローズ
ドアーク溶接法の場合は、溶剤又は溶接棒を使用
するため溶接継手部の品質は添加合金の調合によ
り如何ようにも可能となるが、前者のフラツシユ
バツト圧接法及びガス圧接法の場合は、レールを
電気又はガスにより高温加熱し機械的に圧接する
ものであるから、溶接継手部組成は母材特性に依
存することになる。 On the other hand, the traditional method of connecting rail joints to joint plates by tightening them requires measures to prevent damage, improve ride comfort, and prevent noise, and as part of this, welding is being used to create long rails. rail welding is becoming essential. Rail welding methods include flat butt welding, gas pressure welding, thermite welding, and enclosed arc welding. Of these, two of these methods, flat butt welding and gas pressure welding, are base welding, and thermite welding. method, enclosed arc welding method is adopted for on-site welding. In the case of the latter, thermite welding and enclosed arc welding, solvents or welding rods are used, so the quality of the welded joint can be improved in any way possible by mixing additive alloys; however, in the former, flat butt welding and gas In the case of the pressure welding method, the rail is heated to a high temperature with electricity or gas and mechanically welded under pressure, so the composition of the welded joint depends on the properties of the base material.
ところで、例えば上記(b)のスラツク・クエンチ
レールは、当該熱処理によつてレール頭部を高強
度化したものであるから、フラツシユバツト圧接
或いはガス圧接によつて接合した場合、当該圧接
部は一たんオーステナイト化され、該圧接部が圧
接後そのまま放冷されると、第１図に示す如く非
接合部より硬度が著しく低下したいわゆる軟化部
を生ずる。この現象は前記(a)の焼入―焼戻しレー
ルでも同様に生ずる。この場合、圧接部は粗いパ
ーライト組織を呈し、軟化部を生ずるものであ
る。これの発生原因は第２図に示すように、溶接
後の冷却速度（800〜500℃間を１〜３℃／sec）
が、スラツク・クエンチ時の冷却速度（800〜500
℃間を５〜10℃／sec）に比し小さいことによる
ものであつて、高温側でパーライト変態を生じ硬
度低下をもたらすためである。 By the way, for example, in the slack quench rail shown in (b) above, the rail head has been strengthened by the heat treatment, so when it is joined by flat butt pressure welding or gas pressure welding, the pressure welded part is temporarily When the welded portion is austenitized and left to cool as it is after welded, a so-called softened portion is formed whose hardness is significantly lower than that of the non-welded portion, as shown in FIG. This phenomenon also occurs in the hardened and tempered rail of (a) above. In this case, the pressure welded portion exhibits a coarse pearlite structure, resulting in a softened portion. As shown in Figure 2, the cause of this is the cooling rate after welding (1~3℃/sec between 800~500℃).
However, the cooling rate during slack quench (800 to 500
This is because the temperature is small compared to 5 to 10°C/sec), and pearlite transformation occurs on the high temperature side, resulting in a decrease in hardness.
このように、圧接時当該個所に軟化部が発生す
ると、レール頭部の不均一摩耗や塑性変形をもた
らす原因となり、レール寿命を短くするし、保守
作業上からも重大な問題であり、改良が要望され
ていた。 In this way, if a softened part occurs at the relevant point during pressure welding, it will cause uneven wear and plastic deformation of the rail head, shortening the rail life and also being a serious problem in terms of maintenance work. It was requested.
本発明は、前記熱処理レールを圧接により接合
した場合の問題点を解決するためになされたもの
である。本発明の骨子とするところは、熱処理レ
ールを圧接（溶接）するに際し、軟化部の発生防
止のため圧接後直ちに当該圧接部を加速冷却する
ことにより軟化部の発生を防止するもので、その
冷却方法を特徴とする。 The present invention has been made in order to solve the problems when the heat-treated rails are joined by pressure welding. The gist of the present invention is to prevent the occurrence of softened parts when heat-treated rails are pressure-welded (welded) by accelerating cooling of the welded parts immediately after welding in order to prevent the occurrence of softened parts. Features a method.
即ち、本発明は、焼入―焼戻し又はスラツク・
クエンチを施した熱処理レールをフラツシユバツ
ト圧接又はガス圧接し、当該圧接部がオーステナ
イト域にある間に、接触壁が大なる弾性変形能を
有する薄膜で形成されかつその中を冷却液体が通
過するようにした冷却函を当接し、次いで当該函
内の液体圧力を調整することにより前記接触壁を
レール外形面に沿つて弾性変形させ両者の面接触
状態を維持しつつ当該圧接部の組織を微細パーラ
イトに変態させることを特徴とする熱処理レール
の接合方法である。 That is, the present invention provides hardening-tempering or slack-tempering.
The quenched heat-treated rails are flash butt welded or gas pressure welded, and while the welded portion is in the austenite region, the contact wall is formed of a thin film with large elastic deformability and the cooling liquid passes through it. Then, by adjusting the liquid pressure inside the box, the contact wall is elastically deformed along the outer surface of the rail, and while maintaining the state of surface contact between the two, the structure of the pressed part is changed to fine pearlite. This is a method for joining heat-treated rails characterized by transformation.
本発明の対象とするレールの組成は、特定され
るものではないが、C0.60〜0.85％、Si0.1〜0.8
％、Mn0.7〜1.5％残部鉄および不可避的不純物
からなるものを基本組成とし、必要に応じてこれ
に更にCr0.1〜0.8％、V0.01〜0.1％の１種又は２
種を含有させたものを用いることが好ましい。 Although the composition of the rail targeted by the present invention is not specified, C0.60~0.85%, Si0.1~0.8%
%, Mn0.7-1.5%, balance iron and unavoidable impurities, and if necessary, one or two of Cr0.1-0.8%, V0.01-0.1%
It is preferable to use one containing seeds.
上記組成を有し、スラツク・クエンチ又は焼入
―焼戻しを施すことによりその頭部を高強度とし
た熱処理レールを、フラツシユバツト圧接或いは
ガス圧接し（アプセツト部を機械仕上などでバリ
取りしたのち）、後述する接触式冷却方法により
前記圧接後の当該圧接部を微細パーライトに変態
させることにより軟化部発生を防止するものであ
るが、具体的にはレール頭部の表面が750℃以上
の温度で冷却を開始し、２〜10℃／sec（750〜500
℃間を25〜120秒で冷却）で冷却することにより
行われ、結果として圧接部に非溶接部と同様の品
質を付与するものである。 A heat-treated rail having the above composition and whose head has been made high-strength by being subjected to slack quenching or quenching and tempering is flattened or gas pressure welded (after deburring the upset part by mechanical finishing etc.), The contact cooling method, which will be described later, is used to prevent the occurrence of softened parts by transforming the welded part after the welding into fine pearlite. Specifically, the surface of the rail head is cooled at a temperature of 750°C or higher. 2 to 10℃/sec (750 to 500
This process is carried out by cooling the welded part between 25 and 120 seconds (25 to 120 seconds), and as a result, the pressure welded part has the same quality as the non-welded part.
本発明の方法は、焼入―焼戻し或いはスラツ
ク・クエンチのいずれかに限定したのは、これら
はレール頭部を120Kgｆ／mm以上の高強度とした
ものであるが、その接合を圧接により行つた場合
は、圧接時に当該圧接部がオーステナイト域で加
熱され、次いで放冷されるので熱処理前の材質に
戻り軟化部が発生するからである。 The method of the present invention is limited to either quenching-tempering or slack-quenching because these methods have a high strength rail head of 120 Kgf/mm or more, but the joining is performed by pressure welding. In this case, the pressure welded part is heated in the austenite region during pressure welding and then allowed to cool, so that the material returns to the material before heat treatment and a softened part occurs.
又、本発明の方法において、レールの溶接方法
をフラツシユバツト圧接又はガス圧接のいずかに
限定した理由は、先に説明したように他のテルミ
ツト溶接法又はエンクローズドアーク溶接法によ
るときは、溶接の際に使用する溶剤又は溶接棒に
合金元素を含有させることによつて、溶接部の強
度を如何ようにもコントロールすることが可能で
あり、本発明の方法によるまでもないからであ
る。 In addition, in the method of the present invention, the reason why the rail welding method is limited to either flash butt welding or gas pressure welding is because, as explained earlier, when using other thermite welding methods or enclosed arc welding methods, welding This is because the strength of the welded part can be controlled in any way by including alloying elements in the solvent or welding rod used in the process, and the method of the present invention is not required.
次に、本発明の方法の特徴とする冷却方法につ
いて説明する。レールに最も要求されるのは、そ
の組織を微細パーライトとし、高強度（引張強さ
120Kgｆ／mm以上）を得ることである。第３図に
示すように、オーステナイト化条件、冷却条件と
強度との間には密接な関係がある。すなわち、本
発明におけるレールの圧接工程の如き高温加熱
（1100℃以上）の場合は、微細パーライト組織
（Hvかたさ370〜400）が得られる冷却速度は２〜
10℃／secである。この場合冷却速度が２℃／sec
未満では前記圧接部に発生した軟化部の強度が非
溶接部の強度に劣り、また冷却速度が10℃／sec
を超えるとマルテンサイト組織や中間段階の組織
ができるので、割れ等を発生し易く、耐摩耗性も
十分でなくなるので好ましくない。 Next, a cooling method which is a feature of the method of the present invention will be explained. What is most required for rails is a fine pearlite structure and high strength (tensile strength).
120Kgf/mm or more). As shown in FIG. 3, there is a close relationship between austenitizing conditions, cooling conditions, and strength. In other words, in the case of high-temperature heating (1100°C or higher) such as in the rail pressure welding process of the present invention, the cooling rate at which a fine pearlite structure (Hv hardness 370-400) is obtained is 2-2.
10℃/sec. In this case, the cooling rate is 2℃/sec
If the temperature is less than 10°C/sec, the strength of the softened part generated in the pressure welded part will be inferior to that of the non-welded part, and the cooling rate will be less than 10℃/sec.
Exceeding this is not preferable because a martensitic structure or an intermediate-stage structure is formed, which tends to cause cracks, etc., and the wear resistance becomes insufficient.
冷却開始温度は750℃以上とするのが好ましい。
上記組成のレール鋼のAc3点が750℃近傍であり、
その冷却開始を750℃未満とすると、加速冷却前
に一部パーライト変態が生じて粗いパーライト組
織となり、加速冷却による強度向上の効果が小さ
くなるためである。 The cooling start temperature is preferably 750°C or higher.
The Ac 3 points of the rail steel with the above composition are around 750℃,
This is because if the cooling is started at less than 750°C, pearlite transformation occurs in part before accelerated cooling, resulting in a coarse pearlite structure, which reduces the strength improvement effect of accelerated cooling.
本発明は、前記圧接部の冷却に、先に出願人が
特願昭56−6278号で提案した接触式冷却方法を利
用したものである。前記接触式冷却方法が特に本
発明の圧接部の冷却に適する理由は、
(i) レール頭部のスラツク・クエンチにおいては
頭部のみを加熱し、冷却するものであるから、
圧縮空気によつても微細パーライト組織を得る
ために必要な冷却速度を得ることは可能である
が、レール接合（圧接）にあたつてはレール頭
部のみでなく接合個所のレール全体が高温加熱
されるため圧縮空気では必要な冷却速度を得る
ことが困難である。 The present invention utilizes a contact cooling method previously proposed by the applicant in Japanese Patent Application No. 56-6278 to cool the pressure-welded portion. The reason why the contact cooling method is particularly suitable for cooling the pressure welding part of the present invention is that (i) in slack quenching of the rail head, only the head is heated and cooled;
Although it is possible to obtain the cooling rate necessary to obtain a fine pearlite structure using compressed air, when joining (pressure welding) the rails, not only the rail head but also the entire rail at the joining point is heated to high temperatures. Because of this, it is difficult to obtain the necessary cooling rate with compressed air.
(ii) 噴霧冷却又は水冷による場合は、必要な冷却
速度を得ることは可能であるが、いわゆるハー
ドスポツトを生じ易く、好ましない。(ii) When using spray cooling or water cooling, it is possible to obtain the necessary cooling rate, but so-called hard spots tend to occur, which is not preferable.
(iii) 一方、本発明で利用する接触式冷却方法は、
レール頭部に当接する内壁薄膜の種類、函内に
流す冷却液体の種類、温度、採用する函内圧に
より、冷却速度も広範囲に変化させることが可
能であり、しかも冷却はレール頭部と膜との間
で行われるから、水等の冷却剤が直接触れるこ
となく、従つてハードポストを生ずることがな
い。又、本発明の対象とする圧接による軟化部
のみを合理的に冷却することが可能である。(iii) On the other hand, the contact cooling method used in the present invention is
The cooling rate can be varied over a wide range depending on the type of inner wall thin film that contacts the rail head, the type of cooling liquid flowing into the box, the temperature, and the pressure inside the box. Because the process is carried out between the two, there is no direct contact with coolant such as water, and therefore no hard posts occur. Further, it is possible to rationally cool only the softened portion due to pressure welding, which is the object of the present invention.
圧接による軟化部（フラツシユバツト圧接の場
合は100〜200mm、ガス圧接の場合は250〜400mm）
を均一冷却することを可能とする接触冷却方法を
第４図により説明する。図中の符号２は冷却函で
あり、剛性を有する材料例えば２〜10mm厚の鉄板
で形成された函体２′の下面に当る個所に、大な
る弾性変形能を有する薄膜例えば0.1〜0.3mm厚さ
の金属箔で形成された接触壁１が溶接、ろう付
け、ハンダ付け、又は押え板、パンキンを介して
ねじ止めする等の方法で水密的に固定されてい
る。３は冷却液体の注入口であり、４はその注出
口であり、５，６は夫々弁であつて、冷却液体を
強制的に注入し、注出させ前記弁５，６により冷
却函２の内圧及び流量を調整できる機能となつて
いる。７は冷却函２の内圧を開放する開放バイパ
スであり、８はその遮断弁である。Ｇは圧力計で
ある。前記接触壁１は前述の通り大なる弾性変形
能を有する薄膜で被冷却物体のレール頭部の形状
に対応する〓状にくぼみを持たせた形状に造られ
ており、冷却函２内を通過する冷却液体の函内圧
を高めることによりレール頭部１０へ密着し急冷
が行われるものである。 Softened part due to pressure welding (100 to 200 mm for flat butt welding, 250 to 400 mm for gas pressure welding)
A contact cooling method that makes it possible to cool uniformly will be explained with reference to FIG. Reference numeral 2 in the figure is a cooling box, and the lower surface of the box 2' is made of a rigid material such as a steel plate with a thickness of 2 to 10 mm, and is covered with a thin film having a large elastic deformability, such as 0.1 to 0.3 mm. A contact wall 1 formed of a thick metal foil is fixed in a watertight manner by welding, brazing, soldering, or screwing via a presser plate or punch. 3 is a cooling liquid inlet, 4 is its outlet, and 5 and 6 are valves, respectively, for forcibly injecting and discharging the cooling liquid, and the valves 5 and 6 are used to cool the cooling box 2. It has a function that allows you to adjust the internal pressure and flow rate. 7 is an open bypass for releasing the internal pressure of the cooling box 2, and 8 is a shutoff valve thereof. G is a pressure gauge. As mentioned above, the contact wall 1 is a thin film having a large elastic deformability and is made in a shape with a concave shape corresponding to the shape of the rail head of the object to be cooled, and the contact wall 1 is a thin film having a large elastic deformability. By increasing the pressure inside the box, the cooling liquid comes into close contact with the rail head 10 and is rapidly cooled.
この接触急冷方法を用いて圧接接合が行われた
直後の当該圧接部のレール頭部１０を冷却するに
は、先づ開放バイパス７の遮断弁８を開として冷
却函２の冷却液体内圧を零とし、次いで、第５図
に示す如く冷却函２を前記レール頭部１０へ当接
させ、鉤９によりレール底部１０′へ離脱しない
ようにセツトする。次に開放バイパス７の遮断弁
８を閉とし、冷却函２内の冷却液体の圧力を上げ
る。この時函内圧の上昇により前記冷却函２の函
体２′は剛性のある鉄板で形成されており、接触
壁１は薄膜で形成されているから、この接触壁１
が外方（レール頭部方向）へ向つて膨脹し、その
結果レール頭部１０へ密着する。このレール頭部
１０への接触壁１の密着は、冷却函２の函内圧を
高めれば高める程より接触が密になる訳であり、
この密着により接触壁１を介して冷却液体とレー
ル頭部１０との間に良好な接触伝熱が行われ、伝
熱による熱量は冷却函２内を通過する冷却液体例
えば水により奮熱されるので、レール頭部（圧接
部）の冷却が成立する。 In order to cool the rail head 10 of the pressure-welded part immediately after pressure-welding is performed using this contact quenching method, first open the shutoff valve 8 of the open bypass 7 to bring the internal pressure of the cooling liquid in the cooling box 2 to zero. Then, as shown in FIG. 5, the cooling box 2 is brought into contact with the rail head 10 and set using the hook 9 so that it will not come off to the rail bottom 10'. Next, the shutoff valve 8 of the open bypass 7 is closed, and the pressure of the cooling liquid in the cooling box 2 is increased. At this time, due to the increase in internal pressure of the box, the box body 2' of the cooling box 2 is made of a rigid iron plate, and the contact wall 1 is made of a thin film.
expands outward (toward the rail head), and as a result, comes into close contact with the rail head 10. The closer the contact wall 1 is to the rail head 10, the higher the internal pressure of the cooling box 2 is, the closer the contact becomes.
Due to this close contact, good contact heat transfer is performed between the cooling liquid and the rail head 10 via the contact wall 1, and the amount of heat due to heat transfer is exerted by the cooling liquid, such as water, passing through the cooling box 2. , the rail head (pressing part) is cooled.
最後に、好ましいレールの組成を挙げた理由を
説明すると、Ｃは強度確保上0.60％以上添加する
ことが好ましく、0.85％を超えると粒界に初析セ
メンタイトを生成させ、材質の脆化を引き起すの
で、その添加量を0.60〜0.85％とすることが好ま
しい。Siは脱酸元素として0.10％以上添加するこ
とが好ましく、かつSi量の増加はフエライト地を
強化させ強度向上をもたらし有効である。しかし
0.8％を超えると強度上昇の割合が小さく溶接継
手特性も低下させるので、その添加量を0.1〜0.8
％とすることが好ましい。MnはSiと同様脱酸元
素として添加するものであり、焼入性を上げるた
めに0.6％以上とすることが好ましく、1.5％を超
えると鋼のミクロ偏析によるマルテンサイト組織
を生じ易く、熱処理および溶接時に硬化や脆化を
生じ材質劣化を来すの恐れがあるので0.6〜1.5％
の範囲を添加することが好ましい。Crは0.1％以
上添加するとパーライトラメラー間隔を狭くし高
強度が得られる点で有効な元素であり、0.8％を
超えると焼入性が向上し、本発明の冷却時にマル
テンサイト組織を混入させるきらいがある。その
ようなことから0.1〜0.8％を添加することが好ま
しい。ＶもCrと同様添加により焼入性を上げ、
強度向上をもたらすが、0.1％以上含有させても
その効果は増した量に見合う程大きくなく且つ高
価な元素であるため0.1％以下添加することが好
ましい。 Finally, to explain the reason for listing the preferred composition of the rail, it is preferable to add C in an amount of 0.60% or more to ensure strength.If it exceeds 0.85%, pro-eutectoid cementite is generated at the grain boundaries, leading to embrittlement of the material. Therefore, the amount added is preferably 0.60 to 0.85%. It is preferable to add 0.10% or more of Si as a deoxidizing element, and increasing the amount of Si is effective in strengthening the ferrite base and improving strength. but
If it exceeds 0.8%, the rate of increase in strength will be small and the properties of welded joints will deteriorate, so the amount added should be 0.1 to 0.8%.
% is preferable. Like Si, Mn is added as a deoxidizing element, and is preferably 0.6% or more in order to improve hardenability. If it exceeds 1.5%, martensitic structure is likely to occur due to micro-segregation of the steel, and it is difficult to heat treat. 0.6 to 1.5% as there is a risk of hardening and embrittlement during welding, resulting in material deterioration.
It is preferable to add a range of . When added at 0.1% or more, Cr is an effective element in narrowing the pearlite lamellar spacing and obtaining high strength, and at more than 0.8%, hardenability improves and martensitic structure is less likely to be mixed in during cooling in the present invention. There is. For this reason, it is preferable to add 0.1 to 0.8%. Like Cr, V also improves hardenability by adding
Although it brings about an improvement in strength, even if it is added in an amount of 0.1% or more, the effect is not so great as to correspond to the increased amount, and since it is an expensive element, it is preferable to add it in an amount of 0.1% or less.
次に、本発明の熱処理レールの接合方法を、ス
ラツク・クエンチを施した50Nレールをフラツシ
ユバツト溶接法により接合する場合に適用した実
施例を示す。 Next, an example will be shown in which the heat-treated rail joining method of the present invention is applied to the case where slack-quenched 50N rails are joined by flash butt welding.
冷却条件：
水 温 25℃
水 量 300l／min／m2（接触伝熱面形成面
積当り）
冷却函内圧 １Kg／cm2Ｇ
内壁金属箔 0.2mm厚銅箔
上記の条件による冷却の速度は、第６図に示す
如く4.2〜5.4℃／sec（750〜500℃間、表面下５mm
深さ）であつた。又、水温：80℃で他の条件が上
記と同一の実施例では3.5〜4.5℃／sec（750〜500
℃間、表面下５mm深さ）であつた。この場合の表
面下５mmにおける硬度分布を第７図に示す。第７
図から明らかなように水温25℃の場合は冷却速度
が大きく、圧接部の硬度上昇が大で母材部と同程
度の硬度が得られる。Cooling conditions: Water temperature: 25℃ Water volume: 300l/min/m 2 (per contact heat transfer surface area) Cooling box internal pressure: 1Kg/cm 2 G Inner wall metal foil: 0.2mm thick copper foil The cooling speed under the above conditions is as follows: As shown in Figure 6, 4.2 to 5.4℃/sec (750 to 500℃, 5mm below the surface)
depth). In addition, in an example where the water temperature was 80°C and other conditions were the same as above, the rate was 3.5 to 4.5°C/sec (750 to 500°C).
℃, 5 mm depth below the surface). The hardness distribution 5 mm below the surface in this case is shown in FIG. 7th
As is clear from the figure, when the water temperature is 25°C, the cooling rate is high, and the hardness of the welded part increases greatly, achieving a hardness comparable to that of the base material.
尚、焼入―焼戻し熱処理レールにおいてもレー
ル頭部の硬度そのものは、スラツク・クエンチを
施したものと殆んど差がないので、本発明の方法
によつて接合しても何ら支障はない。 It should be noted that the hardness of the rail head itself in a quenched-tempered heat-treated rail is almost the same as that of a rail that has been subjected to slack quenching, so there is no problem in joining it by the method of the present invention.
第１図は従来方法によるフラツシユバツト圧接
による圧接部の硬度分布を示すグラフ図、第２図
は圧接後の冷却速度と組織硬度の関係を示したグ
ラフ図、第３図加熱温度、冷却速度と組織の関係
を示したグラフ図、第４図は本発明の方法に使用
する接触冷却方法とレール頭部を示す斜傾図、第
５図は接触冷却方法をレールにセツトした状態を
示す断面説明図、第６図は本発明方法よるレール
頭部の冷却速度を示すグラフ図、第７図は本発明
方法と従来方法（放冷）との圧接部硬度分布を示
すグラフ図、である。
１……接触壁、２……冷却函、３……注入口、
４……注出口、５，６……弁、７……開放バイパ
ス、８……遮断弁、９……鉤。
Figure 1 is a graph showing the hardness distribution of the welded part by conventional flash butt welding, Figure 2 is a graph showing the relationship between cooling rate and tissue hardness after pressure welding, and Figure 3 is heating temperature, cooling rate and texture. FIG. 4 is an oblique view showing the contact cooling method used in the method of the present invention and the rail head, and FIG. 5 is a cross-sectional explanatory view showing the contact cooling method set on the rail. , FIG. 6 is a graph showing the cooling rate of the rail head according to the method of the present invention, and FIG. 7 is a graph showing the hardness distribution of the pressure welding part between the method of the present invention and the conventional method (cooling). 1...Contact wall, 2...Cooling box, 3...Inlet,
4... Outlet, 5, 6... Valve, 7... Open bypass, 8... Shutoff valve, 9... Hook.
Claims (1)
た熱処理レールをフラツシユバツト圧接又はガス
圧接し、当該圧接部がオーステナイト域にある間
に、接触壁が大なる弾性変形能を有する薄膜で形
成されかつその中を冷却液体が通過するようにし
た冷却函を当接し、次いで当該函内の液体圧力を
調整することにより前記接触壁をレール外形面に
沿つて弾性変形させ両者の面接触状態を維持しつ
つ当該圧接部の組織を微細パーライトに変態させ
ることを特徴とする熱処理レールの接合方法。1 Heat-treated rails that have been quenched and tempered or slack-quenched are flat-butted or gas-welded, and while the welded portion is in the austenite region, the contact wall is formed of a thin film with large elastic deformability, and the is brought into contact with a cooling box through which a cooling liquid passes, and then by adjusting the liquid pressure inside the box, the contact wall is elastically deformed along the outer surface of the rail, and the surface contact between the two is maintained. A heat-treated rail joining method characterized by transforming the structure of the pressure-welded part into fine pearlite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9215781A JPS57207117A (en) | 1981-06-17 | 1981-06-17 | Joining method for heat treated rail |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9215781A JPS57207117A (en) | 1981-06-17 | 1981-06-17 | Joining method for heat treated rail |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57207117A JPS57207117A (en) | 1982-12-18 |
| JPS6364499B2 true JPS6364499B2 (en) | 1988-12-12 |
Family
ID=14046583
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9215781A Granted JPS57207117A (en) | 1981-06-17 | 1981-06-17 | Joining method for heat treated rail |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57207117A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6256524A (en) * | 1985-09-06 | 1987-03-12 | Nippon Steel Corp | Manufacture of high strength rail providing weldability |
| JP2008545537A (en) * | 2005-06-07 | 2008-12-18 | ユニバーシティ オブ ユタ リサーチ ファウンデーション | Method and system for residual tensile stress reduction |
| JP4869773B2 (en) * | 2006-04-21 | 2012-02-08 | 新日本製鐵株式会社 | Rail flash butt welding method |
| WO2013161026A1 (en) * | 2012-04-25 | 2013-10-31 | Ｊｆｅスチール株式会社 | Pearlite rail, flash butt welding method for pearlite rail, and method for manufacturing pearlite rail |
-
1981
- 1981-06-17 JP JP9215781A patent/JPS57207117A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57207117A (en) | 1982-12-18 |
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