JP3410626B2 - Lap welding method of galvanized steel sheet using laser beam - Google Patents
Lap welding method of galvanized steel sheet using laser beamInfo
- Publication number
- JP3410626B2 JP3410626B2 JP08559597A JP8559597A JP3410626B2 JP 3410626 B2 JP3410626 B2 JP 3410626B2 JP 08559597 A JP08559597 A JP 08559597A JP 8559597 A JP8559597 A JP 8559597A JP 3410626 B2 JP3410626 B2 JP 3410626B2
- Authority
- JP
- Japan
- Prior art keywords
- welding
- output
- galvanized steel
- laser beam
- steel sheet
- 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 - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/02—Iron or ferrous alloys
- B23K2103/04—Steel or steel alloys
Landscapes
- Laser Beam Processing (AREA)
Description
【0001】[0001]
【発明の属する技術分野】本発明は亜鉛めっき鋼板のレ
ーザー重ね溶接方法に関するものである。TECHNICAL FIELD The present invention relates to a laser lap welding method for galvanized steel sheets.
【0002】[0002]
【従来の技術】薄鋼板をレーザー溶接する場合、溶接部
に高い加工精度が要求されるため、突き合わせ溶接より
は重ね溶接が適用される場合が極めて多い。薄鋼板のレ
ーザー溶接は高速、非接触、連続溶接であり、従来多用
されている抵抗溶接より強度、部品の設計裕度において
優れている。しかしめっき鋼板の重ね溶接では重なり部
分のめっき金属が溶接部に欠陥を生じさせることがあ
り、レーザー溶接の際の大きな問題となっている。特に
低融点低沸点の亜鉛がめっき金属の場合には、ブローホ
ール、ピット等亜鉛蒸気に起因する欠陥が数多く発生し
て、溶接部の強度特性を低下させる大きな要因となる。
このため溶接時に発生する亜鉛蒸気を逃がすための方法
が検討されてきた。2. Description of the Related Art When laser welding a thin steel sheet, a lap welding is often applied rather than a butt welding because a high working accuracy is required for a welded portion. Laser welding of thin steel sheets is high-speed, non-contact, continuous welding, and is superior in strength and component design latitude to resistance welding, which has been widely used in the past. However, in the lap welding of plated steel sheets, the plated metal in the overlapping portion may cause defects in the welded portion, which is a major problem in laser welding. In particular, when zinc having a low melting point and a low boiling point is a plated metal, many defects such as blowholes and pits caused by zinc vapor occur, which is a major factor that deteriorates the strength characteristics of the welded portion.
For this reason, methods for escaping zinc vapor generated during welding have been studied.
【0003】特に鋼板の間に隙間をもうけて亜鉛蒸気を
逃がす方法が極めて有効であると多くの報告がなされ
(例えばJ.Heyden, K.Nilssonら,
Proc.6th Int.Conf.Laser
in Manufacturing,93−104,
May, 1989)、まためっき厚さとその際に必要
な鋼板間隙間の定量化も試みられている(R.Akht
er and W.M.Steen, J.Laser
Apprications, Vol.3,No.2
1991)。In particular, many reports have been made that the method of escaping zinc vapor through a gap between steel sheets is extremely effective (for example, J. Heyden, K. Nilsson et al.
Proc. 6th Int. Conf. Laser
in Manufacturing, 93-104,
May, 1989), and the quantification of the plating thickness and the required gap between the steel sheets has been attempted (R. Akht).
er and W. M. Steen, J.M. Laser
Applications, Vol. 3, No. Two
1991).
【0004】これとは別に鋼板間の隙間を設けることな
しに間欠的にレーザービームを入射しかつ波形制御を行
うことにより亜鉛蒸気の発生を抑制することが提案され
ている。(特開平5−50278号公報)。Apart from this, it has been proposed to suppress the generation of zinc vapor by intermittently injecting a laser beam and controlling the waveform without providing a gap between the steel sheets. (JP-A-5-50278).
【0005】[0005]
【発明が解決しようとする課題】しかし、生産技術とし
ては鋼板間に意図的に隙間を設けることは工程上、手間
がかかりコスト上昇を招く。また隙間を精度よく管理す
ることも極めて困難で、特に薄鋼板の溶接の場合隙間が
目的値より大きくなると溶接不良が生じ溶接が不可能に
なる。目的値より小さい場合は当然ブローホール、ピッ
ト等の欠陥が発生することになる。However, as a production technique, intentionally providing a gap between the steel sheets causes labor in the process and raises the cost. Further, it is extremely difficult to accurately control the gap, and particularly in the case of welding thin steel plates, if the gap becomes larger than the target value, welding failure occurs and welding becomes impossible. If it is smaller than the target value, naturally defects such as blow holes and pits will occur.
【0006】特開平5−50278号公報に示されてい
るように、間欠的にレーザービームを入射する方法は亜
鉛蒸気に起因する欠陥の低減には有効ではあるが間欠的
なレーザービームの入射によりスパッタの飛散が多く、
表面性状の悪化・作業性の低下を招くおそれがあり、ま
た間欠レーザービームは連続レーザーと比較して、同一
溶接速度では溶接幅が細くなる傾向があり、その際に重
ね溶接部のせん断強度が低下する欠点がある。As disclosed in JP-A-5-50278, the method of intermittently injecting a laser beam is effective in reducing defects caused by zinc vapor, but the method of intermittently injecting a laser beam A lot of spatter is scattered,
The surface quality may deteriorate and workability may deteriorate, and the intermittent laser beam tends to have a narrower welding width at the same welding speed as compared with the continuous laser beam. There is a drawback to decrease.
【0007】本発明はこれらの問題を解決し、亜鉛めっ
き鋼板のレーザー重ね溶接において健全な溶接部を得る
ことが可能な溶接方法を提供することにある。An object of the present invention is to solve these problems and to provide a welding method capable of obtaining a sound weld in laser lap welding of galvanized steel sheet.
【0008】[0008]
【課題を解決するための手段】本発明は前記課題を解決
するものであって、レーザービームを用いた亜鉛めっき
鋼板の重ね溶接方法において、レーザービームを連続的
に照射しかつ出力を常時変化させることを特徴とする亜
鉛めっき鋼板の重ね溶接方法である。DISCLOSURE OF THE INVENTION The present invention is to solve the above problems, and in a lap welding method for a galvanized steel sheet using a laser beam, the laser beam is continuously irradiated and the output is constantly changed. It is a lap welding method for galvanized steel sheets characterized by the above.
【0009】[0009]
【発明の実施の形態】本発明のレーザー溶接方法は連続
発振のレーザービームを熱源として用い、そのレーザー
ビームを常時照射しつつ、かつ平均出力は貫通溶接が可
能な範囲に収まるようにし、出力が常時変化させるよう
に制御することによって、健全な亜鉛めっき鋼板の重ね
溶接を可能とする。溶接時に発生する亜鉛蒸気は鋼板間
の隙間が全く存在しない場合、レーザー溶接時に生成す
る溶融池、あるいはキーホールから排出されるが、それ
らの排出能力を超えて亜鉛蒸気が発生する場合に、ブロ
ーホールもしくは激しい場合には溶接金属を吹き飛ばす
現象(ピットと称する)が生じる。そのため生成する亜
鉛蒸気量を低減させ、かつ排出能力を高めることが有効
である。BEST MODE FOR CARRYING OUT THE INVENTION The laser welding method of the present invention uses a continuous wave laser beam as a heat source, constantly irradiates the laser beam, and keeps the average output within a range where penetration welding is possible. By controlling so that it constantly changes, it is possible to perform sound lap welding of galvanized steel sheets. Zinc vapor generated during welding is discharged from the molten pool or keyhole generated during laser welding when there is no gap between steel sheets, but when zinc vapor is generated beyond its discharge capacity, it is blown. In the case of a hole or a severe case, a phenomenon (called a pit) of blowing away the weld metal occurs. Therefore, it is effective to reduce the amount of zinc vapor produced and increase the discharge capacity.
【0010】本発明では出力の低い部分では亜鉛蒸気の
発生を押さえ、かつ出力を常時変化させることにより、
溶融池およびキーホールの大きさを変動させ、亜鉛蒸気
を強制的に排出させることにより健全な溶接が可能にな
った。なお、出力変化は貫通溶接が可能な平均出力を維
持する範囲で変化させ、最高出力と最低出力がそれぞれ
平均出力の上下25%以上になり、かつ両者が少なくと
も一秒間に10回以上繰り返されることが望ましい。ま
た出力0の状態を継続させないことによりスパッタの飛
散を押さえ、かつ溶接幅を強度が十分に得られる領域に
維持することが可能である。In the present invention, by suppressing the generation of zinc vapor in the low output portion and constantly changing the output,
By changing the sizes of the weld pool and keyhole and forcibly discharging zinc vapor, sound welding became possible. The output change is changed within a range that maintains the average output capable of penetration welding, the maximum output and the minimum output are 25% or more above and below the average output, and both are repeated at least 10 times per second. Is desirable. Further, by not continuing the state of output 0, it is possible to suppress the scattering of spatter and maintain the welding width in a region where sufficient strength can be obtained.
【0011】[0011]
【実施例】次に本発明のレーザー溶接方法の具体的な実
施例について詳細に説明する。レーザーとしてフラッシ
ュランプで励起される連続発振YAGレーザーを使用し
て溶接を行う場合について述べる。通常の連続発振レー
ザー、間欠型のパルス発振レーザーは図5、6に示すよ
うな出力パターンであるが、フラッシュランプへ供給す
る電流を連続的に変化させることにより図7に示すよう
な出力パターンが得られる。この原理を用いて、1.0
mm厚さの亜鉛めっき鋼板(母材引張強度28kgf/
mm2 )の2枚重ね溶接を2kWYAGレーザーで行
う。今回使用するレーザーは出力変化をさせた場合に得
られる最大出力は4kWである。EXAMPLES Next, specific examples of the laser welding method of the present invention will be described in detail. A case where welding is performed using a continuous wave YAG laser excited by a flash lamp as a laser will be described. Normal continuous wave lasers and intermittent pulsed lasers have output patterns as shown in FIGS. 5 and 6, but the output pattern as shown in FIG. 7 can be obtained by continuously changing the current supplied to the flash lamp. can get. Using this principle, 1.0
mm-thick galvanized steel sheet (base material tensile strength 28 kgf /
mm 2 ) two-layer lap welding is performed with a 2 kW YAG laser. The maximum output of the laser used this time when the output is changed is 4 kW.
【0012】表1に種々のレーザー出力パターンで亜鉛
めっき鋼板を重ね溶接を行った場合の結果を示す。ここ
で、欠陥率は溶接長100mmあたりブローホール、ピ
ットの存在する長さの比で示す。強度はせん断引張試験
結果であり1mm2 あたりの強度である。比較のため通
常の連続発振とパルス発振で鋼板間ギャップを設けて実
験を行った例も示す。Table 1 shows the results when lap welding was performed on galvanized steel sheets with various laser output patterns. Here, the defect rate is indicated by the ratio of the length of blow holes and pits per 100 mm of welding length. The strength is the result of the shear tensile test and is the strength per 1 mm 2 . For comparison, an example is also shown in which an experiment was performed with a gap between steel plates provided by normal continuous oscillation and pulse oscillation.
【0013】表1に示すように従来の連続発振、パルス
発振では欠陥が非常に多く観察される。鋼板間ギャップ
を設けると溶接欠陥は皆無になるが、パルス発振の場合
はスパッタの飛散は多く表面性状が悪い。溶接部の引張
強度も鋼板間ギャップの無い場合とパルス発振の場合は
強度は母材以下であり実用上問題がある。As shown in Table 1, many defects are observed in the conventional continuous oscillation and pulse oscillation. If a gap between the steel sheets is provided, no welding defects will occur, but in the case of pulse oscillation, spatter will be scattered and the surface quality will be poor. Regarding the tensile strength of the welded portion, the strength is less than that of the base metal when there is no gap between the steel sheets and in the case of pulse oscillation, which is a practical problem.
【0014】本発明の出力パターン(図1、2、3、
4)では上記とは全く異なる結果が得られる。特に最高
出力と最低出力が平均出力の上下25%以上離れ、繰り
返し数が10回/秒以上で最も欠陥低減効果が大きい。
また引張強度は母材強度を超えて十分な強度を確保して
いる。The output patterns of the present invention (FIGS. 1, 2, 3,
In 4), a completely different result is obtained. In particular, the maximum output and the minimum output are separated by 25% or more above and below the average output, and the number of repetitions is 10 times / second or more, the greatest defect reduction effect.
Moreover, the tensile strength exceeds the strength of the base metal and secures sufficient strength.
【0015】[0015]
【表1A】 [Table 1A]
【0016】[0016]
【表1B】 ※1. 繰り返し数は1秒間に繰り返されるビーム出力パターン数(単位Hz) ※2. 溶接速度の単位はm/分 ※3. 強度は単位面積あたりの強度(kgf/m2 ) ※4. 連続発振は図5、パルス発振は図6[Table 1B] * 1. The number of repetitions is the number of beam output patterns repeated in 1 second (unit: Hz) * 2. The unit of welding speed is m / min * 3. Strength is strength per unit area (kgf / m 2 ) * 4. Figure 5 shows continuous oscillation and Figure 6 shows pulse oscillation.
【0017】[0017]
【発明の効果】本発明は連続的にレーザービームを照射
しつつかつ出力を常時変化させる方法によって亜鉛めっ
きされた鋼板の重ね溶接を行う場合に鋼板間にギャップ
を設けること無しに欠陥が無く強度の高い健全なレーザ
ー溶接を提供することが可能である。INDUSTRIAL APPLICABILITY In the present invention, when lap welding of galvanized steel sheets is performed by a method of continuously irradiating a laser beam and constantly changing the output, there is no defect between the steel sheets and the strength is high without defects. It is possible to provide high sound laser welding.
【図1】本発明の出力パターンを示す図である。FIG. 1 is a diagram showing an output pattern of the present invention.
【図2】本発明の出力パターンを示す図である。FIG. 2 is a diagram showing an output pattern of the present invention.
【図3】本発明の出力パターンを示す図である。FIG. 3 is a diagram showing an output pattern of the present invention.
【図4】本発明の出力パターンを示す図である。FIG. 4 is a diagram showing an output pattern of the present invention.
【図5】連続発振レーザーの出力パターンを示す図であ
る。FIG. 5 is a diagram showing an output pattern of a continuous wave laser.
【図6】間欠型のパルス発振レーザーの出力パターンを
示す図である。FIG. 6 is a diagram showing an output pattern of an intermittent pulsed laser.
【図7】フラッシュランプへ供給する電流を連続的に変
化させて得られる出力パターンを示す図である。FIG. 7 is a diagram showing an output pattern obtained by continuously changing a current supplied to a flash lamp.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7,DB名) B23K 26/00 - 26/42 ─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. 7 , DB name) B23K 26/00-26/42
Claims (3)
の重ね溶接方法において、レーザービームを時間的に連
続照射しかつ出力を常時変化させることを特徴とする亜
鉛めっき鋼板の重ね溶接方法。1. A lap welding method for a galvanized steel sheet using a laser beam, which comprises continuously irradiating a laser beam with time and constantly changing the output.
な溶接幅を得る目的で、出力ゼロの状態が連続的に存在
しないことを特徴とする請求項1記載の亜鉛めっき鋼板
の重ね溶接方法。2. The lap welding method for a galvanized steel sheet according to claim 1, wherein a zero output state does not continuously exist for the purpose of preventing welding spatter scattering and obtaining a welding width capable of ensuring strength.
せ亜鉛蒸気を除去する目的で、最高出力と最低出力が平
均出力の上下25%以上になり、かつ変動の繰り返し数
が1秒間に10回以上となるように制御することを特徴
とする請求項1又は2記載の亜鉛めっき鋼板の重ね溶接
方法。3. The maximum output and the minimum output are 25% or more above and below the average output for the purpose of varying the size of the molten pool and the keyhole to remove zinc vapor, and the number of repetitions of the variation is 10 per second. The lap welding method for a galvanized steel sheet according to claim 1 or 2, wherein the lap welding is controlled so that the number of times is at least one.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP08559597A JP3410626B2 (en) | 1997-03-21 | 1997-03-21 | Lap welding method of galvanized steel sheet using laser beam |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP08559597A JP3410626B2 (en) | 1997-03-21 | 1997-03-21 | Lap welding method of galvanized steel sheet using laser beam |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH10263858A JPH10263858A (en) | 1998-10-06 |
JP3410626B2 true JP3410626B2 (en) | 2003-05-26 |
Family
ID=13863186
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP08559597A Expired - Fee Related JP3410626B2 (en) | 1997-03-21 | 1997-03-21 | Lap welding method of galvanized steel sheet using laser beam |
Country Status (1)
Country | Link |
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JP (1) | JP3410626B2 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8253062B2 (en) | 2005-06-10 | 2012-08-28 | Chrysler Group Llc | System and methodology for zero-gap welding |
JP2008213004A (en) * | 2007-03-06 | 2008-09-18 | Tokyu Car Corp | Laser welding method and laser welding apparatus |
CN108581197B (en) * | 2018-04-17 | 2020-02-18 | 北京工业大学 | Laser energy modulation welding method |
CN108817670B (en) * | 2018-06-08 | 2020-02-18 | 北京工业大学 | High-power laser-arc hybrid welding energy modulation welding method |
-
1997
- 1997-03-21 JP JP08559597A patent/JP3410626B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
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JPH10263858A (en) | 1998-10-06 |
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