JPH03249127A - Shot peening treatment for rail-welded joint - Google Patents
Shot peening treatment for rail-welded jointInfo
- Publication number
- JPH03249127A JPH03249127A JP4568290A JP4568290A JPH03249127A JP H03249127 A JPH03249127 A JP H03249127A JP 4568290 A JP4568290 A JP 4568290A JP 4568290 A JP4568290 A JP 4568290A JP H03249127 A JPH03249127 A JP H03249127A
- Authority
- JP
- Japan
- Prior art keywords
- rail
- shot peening
- shot
- welded joint
- welding
- 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
- 238000005480 shot peening Methods 0.000 title claims abstract description 33
- 238000003466 welding Methods 0.000 claims abstract description 37
- 238000000034 method Methods 0.000 claims abstract description 29
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- 238000005452 bending Methods 0.000 claims abstract description 7
- 230000007935 neutral effect Effects 0.000 claims abstract description 6
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 5
- 239000010959 steel Substances 0.000 claims abstract description 5
- 239000000463 material Substances 0.000 description 31
- 238000012545 processing Methods 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 238000013001 point bending Methods 0.000 description 5
- 230000007547 defect Effects 0.000 description 4
- 238000003754 machining Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000009661 fatigue test Methods 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 241001504592 Trachurus trachurus Species 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000003832 thermite Substances 0.000 description 2
- 238000005266 casting Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000012795 verification 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）
この発明は、鉄道用レールを現地あるいは工場において
溶接する場合の、溶接継手部の疲労強度を向上するため
のショットピーニング処理方法に関するものである。[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a shot peening treatment method for improving the fatigue strength of a welded joint when welding railway rails on-site or in a factory. .
（従来の技術）
鉄道用レールの溶接継手はロングレール敷設およびその
補修時に不可欠な要素である。レールの現地における溶
接方法としては、まずエンクローズ溶接法が挙げられる
。この場合、溶接余盛は完全に除去されるので応力集中
がなく、さらに後熱処理を受けるために＾い疲労強度を
示すが、作業能率が低く、たとえば特開昭５６−４３５
０号公報に記載されているような、作業能率向上と共に
狭開先による施工によって溶接時に発生する欠陥を防ぐ
ものや、特開昭６３−１６０７９９号公報に記載されて
いるような、＾炭素系溶接棒を用いた溶接で欠陥と割れ
の発生を防止することにより継手部信頼性を得る技術が
ある。(Prior Art) Welded joints for railway rails are essential elements when laying and repairing long rails. The first example of on-site welding methods for rails is the enclosure welding method. In this case, the welding excess is completely removed, so there is no stress concentration, and since it is subjected to post-heat treatment, it exhibits high fatigue strength, but the work efficiency is low.
0, which improves work efficiency and prevents defects that occur during welding due to narrow gap construction, and carbon-based There is a technology that improves the reliability of joints by preventing the occurrence of defects and cracks in welding using welding rods.
テルミット溶接法はたとえば溶接学会誌第５４巻第１号
（１９８５年）第４３〜４９頁に記載されているように
公知の技術であるが、この信頼性を向上する技術は、た
とえば特開昭５３−２９６４９号公報および特開昭５３
−２９６５０号公報に記載されているように溶接時の予
熱温度や溶剤量および余盛形状を管理することによるも
のである。The thermite welding method is a well-known technique, as described in, for example, Journal of the Welding Society, Vol. 54, No. 1 (1985), pages 43-49. Publication No. 53-29649 and Japanese Unexamined Patent Publication No. 1983
This is done by controlling the preheating temperature, the amount of solvent, and the shape of the extra layer during welding, as described in Japanese Patent No. 29650.
さらに、たとえば特開昭６０ｍｍ５４１４６号公報に記
載されているような、サブマージアーク溶接とエレクト
ロスフグ溶接を併用した自動溶融溶接法があるが、スラ
グの巻き込みと融合不良を防止することにより健全な溶
接継手部を得ることを目的とした技術である。Furthermore, there is an automatic fusion welding method that uses a combination of submerged arc welding and electrosphragm welding, such as that described in Japanese Patent Application Laid-Open No. 60mm54146. This is a technique aimed at obtaining joints.
以上のように、溶接時に発生する欠陥を未然に防止して
、その結果としてレール溶接継手部の信頼性を高める技
術があるが、実溶接作業時における欠陥の発生を皆無に
することはできないし、溶接時の材質的な劣化、および
溶接継手部に発生する残留応力や余盛部における応力集
中のために必ずしも＾い信頼性を有しているとはいえず
、したがって保守・点検が重要となる。そこで、ショッ
トピーニング処理加工により表面亀裂の発生を防止する
と信頼性を向上させる効果が＾い。As mentioned above, there are technologies that can prevent defects that occur during welding and, as a result, increase the reliability of rail welded joints, but it is not possible to completely eliminate defects that occur during actual welding work. However, due to material deterioration during welding, residual stress generated in the welded joint, and stress concentration in the reinforcement, it cannot necessarily be said that it has high reliability, so maintenance and inspection are important. Become. Therefore, preventing the occurrence of surface cracks by shot peening is effective in improving reliability.
ショットピーニング処理方法は、加工による表面硬化と
表面圧縮残留応力の発生によって疲労強度寿命を＾める
表面処理方法として、従来からたとえば自動車用のバネ
部材などに対して用いられており、鋼製小球を＾速度で
多数投射することによって材料表面を加工する処理法で
ある。バネ部材のような比較的小さな対象物の場合は、
表面加工の影響が顕著に生じるために表面硬度や残留応
力値のみを追及すればよいが、レール溶接継手部の場合
は形状のみならず材質も異なるため、バネ部材に対する
投射の条件をそのままレール溶接継手部に適用すること
はできない。また、溶接または鋳造によって製造される
レールクロッシング部にショットピーニング処理が施さ
れることがあるが、製造過程において処理されるもので
あり、さらに具体的な処理条件については定量的な指標
がない。Shot peening is a surface treatment method that prolongs fatigue strength life by hardening the surface and generating surface compressive residual stress, and has traditionally been used for automobile spring members, etc. This is a processing method that processes the surface of a material by projecting a large number of balls at ^ speed. For relatively small objects such as spring members,
Since the influence of surface processing is noticeable, it is only necessary to investigate the surface hardness and residual stress values, but in the case of rail welded joints, not only the shape but also the material differs, so rail welding can be performed without changing the projection conditions for the spring member. It cannot be applied to joints. In addition, shot peening is sometimes applied to rail crossings manufactured by welding or casting, but this treatment is performed during the manufacturing process, and there are no quantitative indicators regarding specific treatment conditions.
（発明が解決しようとする課題）
このように、レールの溶接継手部に存在する残留応力や
材質劣化によって疲労強度が低下することが必然であり
、このためにショットピーニング処理が有効であると考
えられる。本発明は、従来主として自動重用部材等の小
部品に対して施されてきたショットピーニング処理を、
厚肉部材に適用するための最適加工条件を明確化するも
のであり、材料が有する機械的特性と負荷応力状態に鑑
みて、投射される材料および投射条件による残留応力値
と加工深度の関係および疲労強度の検証から、ショット
ピーニング時における各処理条件を具体的に提供するも
のである。(Problem to be solved by the invention) As described above, fatigue strength inevitably decreases due to residual stress and material deterioration existing in the welded joints of rails, and shot peening treatment is considered to be effective for this purpose. It will be done. The present invention improves shot peening treatment, which has traditionally been applied mainly to small parts such as automatic heavy duty parts.
The purpose is to clarify the optimal processing conditions for applying to thick-walled parts, and to clarify the relationship between the residual stress value and processing depth depending on the material being projected and the projection conditions, taking into account the mechanical properties and loaded stress state of the material. From the verification of fatigue strength, each treatment condition during shot peening is specifically provided.
（課題を解決するための手段）
本発明は、レール溶接継手部に対して直径が１．０ｍｍ
以上１．８１以下でＨＲＣスケールで４８以上６０以下
の硬度を有する鋼製小球によってショットピーニング処
理することを特徴とするレール溶接継手部のショットピ
ーニング処理方法である。(Means for Solving the Problems) The present invention provides a rail welded joint with a diameter of 1.0 mm.
This is a shot peening treatment method for a rail weld joint, characterized in that the shot peening treatment is performed using a steel ball having a hardness of 48 or more and 60 or less on the HRC scale, which is 1.81 or less.
ショットピーニングの投射密度を４００ ｋｇｆ／ｍ’
以上１０００ ｋＨｆ／ｍ２以下とすること、レール溶
４１１部の曲げ中立軸よりＦ方のウェブ両面と足部の表
裏部にショットピーニング処理すること、レール溶接施
工後に５００℃以上６５０℃以ドの温度に３０秒以上保
持する溶接後熱処理を施′した後にショットピーニング
処理することは好ましい。Shot peening projection density to 400 kgf/m'
1000 kHf/m2 or less, shot peening treatment on both sides of the web in the F direction from the neutral axis of bending of the rail welding section 411 and the front and back of the foot, and a temperature of 500°C or more and 650°C or less after rail welding. It is preferable to carry out shot peening treatment after carrying out post-weld heat treatment for 30 seconds or more.
（作用）
レールの実使用時における荷重形態はいわゆる三点曲げ
応力状態であり、そのときの応力分布は設計上の曲げ中
立軸より上方がレール長手方向に圧縮、下方が引張応力
となる。最も引張応力値が厳しい箇所は足裏面であり、
その値は足表面の約１．６７倍である。さらに、溶接継
手部には全盛止燈部の形状効果に−よって応力集中が生
じ、その値は１．２５倍程度にも達する場合がある。こ
のように、三点曲げ荷重負荷時に足裏面の溶接継手部に
は相当に＾い値の引張応力が作用している。(Function) The load form during actual use of the rail is a so-called three-point bending stress state, and the stress distribution at that time is compressive stress in the longitudinal direction of the rail above the designed bending neutral axis, and tensile stress below. The area with the most severe tensile stress value is the sole of the foot.
Its value is approximately 1.67 times that of the foot surface. Furthermore, stress concentration occurs in the welded joint due to the shape effect of the full stop light part, and the stress concentration may reach about 1.25 times. In this way, when a three-point bending load is applied, a considerably high tensile stress acts on the welded joint on the sole of the foot.
さらに、溶接継手部には、溶接方法による発生箇所の相
違はあるが、材料の降伏応力に近い引張残留応力が発生
する。足表面にこの高い値の引張残留応力が発生した場
合には、荷重負荷時の応力値が低い足表面から疲労亀裂
の発生を見ることもあり、有害である。また、溶接部は
急加熱・急冷却の熱サイクルを受け、たとえば材料の伸
びが１０％にも達しない脆化した領域であって、発生し
た亀裂の進展を抑える能力が低く危険であり、表面処理
等による対策や材質制御が必要となる。Furthermore, tensile residual stress close to the yield stress of the material is generated in the welded joint, although the location differs depending on the welding method. If this high value of tensile residual stress occurs on the foot surface, fatigue cracks may occur from the foot surface where the stress value is low during load application, which is harmful. In addition, welded parts are subjected to thermal cycles of rapid heating and cooling, resulting in brittle areas where the elongation of the material does not reach 10%, for example, and the ability to suppress the propagation of cracks that occur is low and dangerous. Measures such as processing and material control are required.
以上のように、残留応力・負荷応力・材質ともに不利な
溶接継手部の疲労強度を向上させるには、ショットピー
ニング処理による表面圧縮残留応力によって亀裂の発生
を防止することが有効である。As described above, in order to improve the fatigue strength of welded joints that are disadvantageous in terms of residual stress, applied stress, and material, it is effective to prevent the occurrence of cracks by applying surface compressive residual stress through shot peening treatment.
加えて、レールのように比較的肉厚が厚い部材に対して
は、ショットピーニングによる加工深度を深めることが
処理効果を明確化するために必要である。In addition, for relatively thick members such as rails, it is necessary to deepen the processing depth by shot peening in order to clarify the processing effect.
ショットピーニング処理において重要なのは投射される
鋼製小球（以下、投射材という）の形状および硬度であ
る。投射を受けるレール（以下、被投射材という）に対
しである程度の範囲で高い硬度の投射材を使用する必要
があり、その範囲内でも＾い値の表面圧縮残留応力値を
得るには被投射材硬度から、ロックウェル硬さのＣスケ
ールＨＲ９で４８以上、好ましくは５０以上で、６０以
ドの硬度の投射材を用いることが必要である。この範囲
の硬度の投射材を用いた場合には５０ ｋ、ｆ／１１以
上の表面圧縮残留応力を得ることが可能であり、低い硬
度の投射材を使用した場合は残留応力値が低く、また＾
い硬度の投射材を使用すると最表面層で加工軟化が顕著
となり効果が低減する。What is important in the shot peening process is the shape and hardness of the shot steel pellets (hereinafter referred to as shot material). It is necessary to use a shot material with high hardness within a certain range for the rail that receives the shot (hereinafter referred to as the shot material), and even within that range, in order to obtain a high surface compressive residual stress value, In terms of material hardness, it is necessary to use a shot material having a hardness of 48 or more, preferably 50 or more, and 60 degrees or more on the Rockwell hardness C scale HR9. If a shot material with hardness in this range is used, it is possible to obtain a surface compressive residual stress of 50 k, f/11 or more, and if a shot material with a lower hardness is used, the residual stress value will be low. ^
If a shot material with a high hardness is used, processing softening will be noticeable in the outermost layer, reducing the effectiveness.
また、投射材の粒形状は被投射材の表面に切り欠きが発
生しない球形で、その直径は加工深度と表面粗度に影響
し、その範囲は１．０ｍ−以上、好ましくは１．４−一
以上、１．８１以ｒである。投射材直径が小さい場合に
は加工層深度が＾々５０μ−程度にしかならず、肉厚が
厚いためその効果が低く、また投射材の打痕で表面状態
が劣化して亀裂発生が容易となる。投射材直径を上記範
囲より大きくしても加工深度の増大効果は少なく、また
投射効率が悪くなるために適当でない。In addition, the particle shape of the shot material is spherical so that notches do not occur on the surface of the shot material, and its diameter affects the machining depth and surface roughness, and the range is 1.0 m or more, preferably 1.4 m. 1 or more and 1.81 or more. When the diameter of the shot material is small, the depth of the processed layer is only about 50 .mu.m, and the effect is low because of the thick wall, and the surface condition deteriorates due to the dents of the shot material, making it easy to generate cracks. Even if the diameter of the shot material is made larger than the above range, the effect of increasing the machining depth will be small and the shooting efficiency will deteriorate, so it is not appropriate.
投射材の投射量は投射密度として単位面積当りの投射材
重量によって表すが、２００ ｋｇｆ／ｍ”以上の投射
密度によってほぼ全面の処理が実現され、４００ ｋｇ
ｆ／曽２以上２以上投射残留応力値と加工深度共に安定
した値が得られるが、１０００ ｋｇｆ／ｍ２超投射す
ると過度な加工による表面軟化が顕著になる。The amount of shot material shot is expressed by the weight of shot material per unit area as the shot density, and treatment of almost the entire surface is achieved with a shot density of 200 kgf/m" or more, and 400 kg
f/so2 or more 2 or more Stable values can be obtained for both the residual stress value and the machining depth, but when the projection exceeds 1000 kgf/m2, surface softening due to excessive machining becomes noticeable.
投射速度に関しては特に範囲を定めないが、通常のショ
ットピーニング処理時の速度またはそれよりやや遅い速
度でよく、投射初速度は６０〜１００ｍ／秒の範囲が好
適である。There is no particular range for the projection speed, but it may be the speed of normal shot peening treatment or a slightly slower speed, and the initial projection speed is preferably in the range of 60 to 100 m/sec.
上述したように、荷重付加時の長手方向引張応力は設計
上の曲げ中立軸より下方にのみ発生するので、疲労強度
向上の手段としては曲げ中立軸より下方だけ、すなわち
ウェブ両面の下方に適用することで充分である。足表面
での応力値は足裏面より充分に低い値であるが、溶接残
留応力によりて疲労亀裂の発生点となることがあるため
足表面にもショットピーニング処理を施す必要がある。As mentioned above, longitudinal tensile stress occurs only below the designed bending neutral axis when a load is applied, so as a means of improving fatigue strength, it is applied only below the bending neutral axis, that is, below both sides of the web. That is enough. Although the stress value on the foot surface is sufficiently lower than that on the sole surface, it is necessary to apply shot peening treatment to the foot surface as well, since residual stress from welding can cause fatigue cracks to occur.
足裏面においては全面でほぼ均一な長手方向引張応力が
発生するため、その幅方向には全面に均一なショットピ
ーニング処理を施す必要がある。また、溶接時の熱影響
は数１０ｍｍの範囲であるので、溶接継手部を中心にし
て艮手力向は＾々１００＋＋＋ｍずつの範囲をショット
ピーニング処理すれば充分である。Since longitudinal tensile stress is generated almost uniformly over the sole surface of the foot, it is necessary to perform shot peening treatment uniformly over the entire surface in the width direction. Furthermore, since the thermal effect during welding is in the range of several tens of millimeters, it is sufficient to perform shot peening over a range of approximately 100 +++ m in the direction of force around the weld joint.
さらに、安定して高い疲労か命強度を得るためには、溶
接後熱処理を施した後にシラントビ−二ング処理を実施
することが好ましい。すなわち、ショットピーニングに
よって制御可能な領域は材料表面から１００μ−程度の
範囲であり、溶接によって急加熱・急冷却された材料内
部に残留する内部歪を除去することはできない。溶接継
手部およびその近傍を５００°Ｃ以上６５０°Ｃ以下の
範囲の温度で３０秒以上保持することによって鋼材内部
に含まれる炭素が球状化して安定し、破断伸びは１０％
以下であった状態から２０％以上に増大して疲労亀裂の
進展に対する抵抗が増す、また材料の比例限度が６０ｋ
ｇｆ／１１であった状態から８０ｋｇｆ／簡−２となり
、弾性範囲の拡大により疲労寿命が伸びる。５００℃未
満の温度ではこの効果が充分には生じず、６５０℃超の
温度では材料が軟化して疲労強度は低下する。Furthermore, in order to stably obtain high fatigue strength and life strength, it is preferable to perform silant beading treatment after performing post-weld heat treatment. That is, the range that can be controlled by shot peening is about 100 microns from the surface of the material, and it is not possible to remove the internal strain that remains inside the material that has been rapidly heated and cooled by welding. By holding the welded joint and its vicinity at a temperature in the range of 500°C to 650°C for 30 seconds or more, the carbon contained within the steel becomes spheroidized and stabilized, and the elongation at break is 10%.
The resistance to fatigue crack growth increases by more than 20% from below, and the proportional limit of the material increases to 60k.
From gf/11 to 80 kgf/si-2, the fatigue life is extended due to the expansion of the elastic range. At temperatures below 500°C, this effect is not sufficiently produced, and at temperatures above 650°C, the material softens and the fatigue strength decreases.
（実施例）
試験体はＲＥ １３２１ｂｓ＃ｔ （北米仕様）および
Ｊ Ｉ Ｓ ６０ ｋｇｆ／ｍのレールをエンクローズ
溶接法、テルミット溶接法および自動溶融溶接法によっ
て溶接したものであって、溶接後熱処理およびシ壺ット
ピーニングの処理条件を第１表に示し、第１図に三点曲
げ疲労試験の結果を示した６曲げ荷重は溶接部に負荷し
、応力値は足裏面における公称値にて表示している。試
験体の製作条件は各溶接法において同じであり、同一溶
接法の範囲で本発明の効果を比較・検証する。溶接法が
異なるときには試験体が異なり、さらにエンクローズ溶
接法の場合には前述したように溶接部％を完全に除去し
て後熱処理を実施するのが通常であるので、これを比較
の基本条件としたため他の溶接法よりも高い値の疲労強
度を示している。(Example) The test specimen was a rail of RE 1321bs#t (North American specification) and JIS 60 kgf/m welded by the enclosure welding method, thermite welding method, and automatic fusion welding method, and was heat treated after welding. Table 1 shows the processing conditions for the and seat peening, and Figure 1 shows the results of the three-point bending fatigue test.6 The bending load was applied to the welded part, and the stress value was expressed as the nominal value on the sole surface. ing. The test specimen manufacturing conditions are the same for each welding method, and the effects of the present invention will be compared and verified within the same welding method. When the welding method is different, the test specimen is different, and in the case of the enclosed welding method, as mentioned above, it is normal to completely remove the welded area and perform post-heat treatment, so this is the basic condition for comparison. Therefore, it shows a higher fatigue strength than other welding methods.
三点曲げ疲労試験において、ショットピーニング処理を
施さない状態に対し、投射材硬度（ＨＲｅ）と粒径がそ
れぞれ４８．０．８論−の投射材を使用してシ１ットビ
ーニング処理を行ったときの疲労寿命は１．５倍しか増
加しないのに対して、４８．１．２箇−の場合は４倍、
１．４曽−の場合は１２倍、５３．１．４−一の場合は
２０倍の疲労寿命を得ることができた。投射密度が４０
０ ｋｇｆ／簡２と８００ｋｇｆ／鋤２の場合、シタッ
トビーニング処理の程度を表すアークハイトの値は差異
が明確であるが、三点曲げ疲労寿命の差異は少ない、自
動溶融溶接法による試験体を用いて、後熱処理をした後
に適切な処理条件によってシシットビー二ング処理した
場合には、たとえば公称応力２３ｋｇｆ／ｍ論”で疲労
試験したと鯵に疲労限度以上の強度を有した。In a three-point bending fatigue test, when shot peening was performed using shot material with a shot peening hardness (HRe) and particle size of 48.0. The fatigue life of 48.1.2 increases by only 1.5 times, while that of 48.1.2 increases by 4 times.
In the case of 1.4-1, the fatigue life was 12 times longer, and in the case of 53.1.4-1, the fatigue life was 20 times longer. Projection density is 40
There is a clear difference in the arc height value, which indicates the degree of sitt beaning, between 0 kgf/simp 2 and 800 kgf/plow 2, but there is little difference in the three-point bending fatigue life of the test specimen made using the automatic fusion welding method. When the horse mackerel was subjected to a post-heat treatment and then subjected to a hard beaning treatment under appropriate treatment conditions, the horse mackerel had a strength exceeding the fatigue limit when subjected to a fatigue test at a nominal stress of 23 kgf/m, for example.
実際の鉄道での負荷荷重は一回当り高々１５トン程度（
応力値で約１０ ｋｇｆ／ｍｍ２）であるので、本発明
によるシ謄フトビーニング処理により信頼性の＾い溶接
継手強度を保証することが可能となる。The actual load on railways is about 15 tons at most (
Since the stress value is approximately 10 kgf/mm2), the shaft beaning treatment according to the present invention makes it possible to guarantee reliable welded joint strength.
（発明の効果）
鉄道軌道においてロングレールの使用が普及し、種々の
溶接方法が提唱されているなかで、溶接継手部の信頼性
が要求されている。溶接部は溶融・凝固の過程において
その材質を適切に制御することが困難であり、シシット
ビーニングによる表面強化処理によって、実使用状況に
対する強度すなわち疲労強度が向上することの意義は大
きい。疲労強度を向上させるための処理条件を定量化し
たためこれを実現する処理機が明確化され、作業が容易
でさらに短時間で処理可能となって高い信頼性が得られ
るという顕著な効果がある。(Effects of the Invention) As the use of long rails on railway tracks becomes widespread and various welding methods are proposed, reliability of welded joints is required. It is difficult to properly control the material properties of welded parts during the melting and solidification process, and it is of great significance that surface strengthening treatment using shishit beaning improves the strength against actual usage conditions, that is, fatigue strength. Since the processing conditions for improving fatigue strength have been quantified, the processing machine that achieves this has been clarified, which has the remarkable effect of making the process easier, faster, and more reliable.
第１図は本発明による疲労強度の向上を示す図である。 FIG. 1 is a diagram showing the improvement in fatigue strength according to the present invention.
Claims (4)
１．８ｍｍ以下でＨ＿Ｒ＿Ｃスケールで４８以上６０以
下の硬度を有する鋼製小球によってショットピーニング
処理することを特徴とするレール溶接継手部のショット
ピーニング処理方法。(1) The rail weld joint is shot peened using small steel balls with a diameter of 1.0 mm or more and 1.8 mm or less and a hardness of 48 or more and 60 or less on the H_R_C scale. shot peening treatment method.
ｍ＾２以上１０００ｋｇｆ／ｍ＾２以下とすることを特
徴とする請求項１記載のレール溶接継手部のショットピ
ーニング処理方法。(2) Shot peening projection density to 400kgf/
2. The shot peening treatment method for a rail welded joint according to claim 1, wherein the shot peening treatment method is at least m^2 and at most 1000 kgf/m^2.
と足部の表裏部にショットピーニング処理することを特
徴とする請求項１または２記載のレール溶接継手部のシ
ョットピーニング処理方法。(3) The method for shot peening a rail weld joint according to claim 1 or 2, wherein shot peening is performed on both sides of the web below the neutral bending axis of the rail weld and the front and back of the foot.
温度に３０秒以上保持する溶接後熱処理を施した後にシ
ョットピーニング処理することを特徴とする請求項１〜
３のいずれか記載のレール溶接継手部のショットピーニ
ング処理方法。(4) After rail welding, post-weld heat treatment is performed by holding the rail at a temperature of 500°C or more and 650°C or less for 30 seconds or more, and then shot peening treatment is performed.
3. The shot peening treatment method for a rail weld joint according to any one of Item 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4568290A JPH03249127A (en) | 1990-02-28 | 1990-02-28 | Shot peening treatment for rail-welded joint |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4568290A JPH03249127A (en) | 1990-02-28 | 1990-02-28 | Shot peening treatment for rail-welded joint |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03249127A true JPH03249127A (en) | 1991-11-07 |
Family
ID=12726165
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4568290A Pending JPH03249127A (en) | 1990-02-28 | 1990-02-28 | Shot peening treatment for rail-welded joint |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03249127A (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05255735A (en) * | 1992-03-11 | 1993-10-05 | Nippon Steel Corp | Improvement of fatigue strength of weld zone of rail |
| US5393433A (en) * | 1992-03-11 | 1995-02-28 | Aquasource, Societe En Nom Collectif | Method using separation membranes to treat a fluid containing matter in suspension and in solution |
| JP2008274745A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long welded rail and manufacturing method for the same |
| JP2008274414A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long rail and manufacturing method therefor |
| JP2008274415A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long rail and manufacturing method therefor |
| WO2010109837A1 (en) | 2009-03-27 | 2010-09-30 | 新日本製鐵株式会社 | Device and method for cooling welded rail section |
| WO2010116680A1 (en) | 2009-03-30 | 2010-10-14 | 新日本製鐵株式会社 | Method of cooling welded rail section, device for cooling welded rail section, and welded rail joint |
| KR101114528B1 (en) * | 2009-11-11 | 2012-02-27 | 한국생산기술연구원 | Method for Treating the Surface of Steel Welding Joint |
| JP2012107503A (en) * | 2007-03-30 | 2012-06-07 | Nippon Steel Corp | Manufacturing method of long rail |
| US10144983B2 (en) | 2011-05-25 | 2018-12-04 | Nippon Steel and Sumitomo Metal Corporation | Method of reheating rail weld zone |
| US10544479B2 (en) | 2014-04-08 | 2020-01-28 | Nippon Steel Corporation | Heat treatment device, heat treatment method, and rail steel |
-
1990
- 1990-02-28 JP JP4568290A patent/JPH03249127A/en active Pending
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05255735A (en) * | 1992-03-11 | 1993-10-05 | Nippon Steel Corp | Improvement of fatigue strength of weld zone of rail |
| US5393433A (en) * | 1992-03-11 | 1995-02-28 | Aquasource, Societe En Nom Collectif | Method using separation membranes to treat a fluid containing matter in suspension and in solution |
| JP2012132308A (en) * | 2007-03-30 | 2012-07-12 | Nippon Steel Corp | Manufacturing method of long rail |
| JP2008274414A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long rail and manufacturing method therefor |
| JP2008274415A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long rail and manufacturing method therefor |
| JP2012107503A (en) * | 2007-03-30 | 2012-06-07 | Nippon Steel Corp | Manufacturing method of long rail |
| JP2008274745A (en) * | 2007-03-30 | 2008-11-13 | Nippon Steel Corp | Long welded rail and manufacturing method for the same |
| JP2013053373A (en) * | 2007-03-30 | 2013-03-21 | Nippon Steel & Sumitomo Metal Corp | Method for manufacturing long rail |
| WO2010109837A1 (en) | 2009-03-27 | 2010-09-30 | 新日本製鐵株式会社 | Device and method for cooling welded rail section |
| US8353443B2 (en) | 2009-03-27 | 2013-01-15 | Nippon Steel Corporation | Device and method for cooling rail weld zone |
| WO2010116680A1 (en) | 2009-03-30 | 2010-10-14 | 新日本製鐵株式会社 | Method of cooling welded rail section, device for cooling welded rail section, and welded rail joint |
| US8557064B2 (en) | 2009-03-30 | 2013-10-15 | Nippon Steel & Sumitomo Metal Corporation | Method of cooling rail weld zone, and rail weld joint |
| KR101114528B1 (en) * | 2009-11-11 | 2012-02-27 | 한국생산기술연구원 | Method for Treating the Surface of Steel Welding Joint |
| US10144983B2 (en) | 2011-05-25 | 2018-12-04 | Nippon Steel and Sumitomo Metal Corporation | Method of reheating rail weld zone |
| US10544479B2 (en) | 2014-04-08 | 2020-01-28 | Nippon Steel Corporation | Heat treatment device, heat treatment method, and rail steel |
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