Grant-in-Aid for Developmental Scientific Research (B).
|Research Institution||Osaka University|
MATSUNAWA Akira Welding Research Institute, Osaka University, Professor, 溶接工学研究所, 教授 (20029119)
宮田 修 日本電装(株), 第1生産技術部, 係長
数藤 和義 ミヤチテクノス(株), 開発技術部, 主任
藤井 義正 ミヤチテクノス(株), 開発技術部, 部長
KATAYAMA Seiji Welding Research Institute, Osaka University, Assistant, 溶接工学研究所, 助手 (10144528)
TAKEMOTO Tadashi Welding Research Inst., Osaka University, Associate Professor, 溶接工学研究所, 助教授 (60093431)
内田 高弘 ミヤチテクノス(株), 開発部, 課長
斉藤 実 ミヤチテクノス(株), 開発部, 次長
SAITOH Minoru Miyachi Technos Co.Ltd., R&D Division, Senior Manager
UCHIDA Takahiro Miyachi Technos Co.Ltd., R&D Division, Manager
MIYATA Osamu Nippon Denso Co.Ltd., No.1 Production Engineering Division, Manager
|Project Fiscal Year
1991 – 1993
Completed(Fiscal Year 1993)
|Budget Amount *help
¥12,500,000 (Direct Cost : ¥12,500,000)
Fiscal Year 1993 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1992 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1991 : ¥7,400,000 (Direct Cost : ¥7,400,000)
|Keywords||Laser / Pulsed Laser / Laser Welding / Pulse Shaping / Porosity / Solidification Crack / Rapid Solidification / Microsegregation / レーザ / パルスレーザ / レーザ溶接 / 波形制御 / ポロシティー / 凝固割れ / 急速凝固 / ミクロ偏析 / 波系制御 / レーザー / レーザー加工 / パルスレーザー / レーザープラズマ / 逆制動放射 / 散乱 / 溶接欠陥 / 高温割れ / レ-ザ- / レ-ザ-加工 / パルスYAGレ-ザ- / パルス発振波形 / ポロシティ / スポット溶接 / 溶接性 / 金属材料|
1) Determination of Optimum Pulse Shape for Laser Processing (Conducted by A.Matsunawa and S.Katayama)
Austenetic stainless steels and aluminium alloys are known as difficult materials for welding because of formations of various defects such as porosity and crack formations, particularly, in pulsed laser welding. In ordert to eleiminate or suppress these defects, theoretical and experimental works were conducted by considering laser irradiation conditions as well as material's constants, and optimum pulse shape and its allied parameters for each material were determined to drastically eliminate defects formation.
2) Fusion and Solidification Characteristics of Pulse Shaped Laser Welding and Construction of Mathematical Model (Conducted by A.Matsunawa, T.Takemoto and S.Katayama)
Mathematical models of fusion and solidification of conduction mode laser spot welding and microsegregation of laser rapidly quenched weld metal were developed considering the latent heat of fution, and the calcul
ated growth rate of dendrite and distribution of microsegregation were experimentally verified. The developed models were proved to be effective to predict the optimum shape to suppress the solidification crack.
3) Application of Pulse Shaped YAG Laser to Welding of Automotive Parts used Free Cutting Stainless Steel (Conducted by S.Katayama and O.Miyata)
In free cutting stainless steels, elements such as Sulpher and Bismas are added to the metal to improve the cutting propertiy but it greatly deteriorates the weldability in fusion welding because of solidification cracking. In this work, the newly developed pulse shaped YAG laser welding was applied to weld the free cutting stainless steel to ordinary austenetic stainless steel in automotive part, and crack free weld was obtained successfully.
4) Optimization and Improvement of Power Source of Pulse Shapable YAG Laser and Beam Delivery by Optical Fiber (Conducted by A.Matsunawa, M.Saitoh and T.Uchida)
A power source which enabled the pulse shaping of YAG laser was developed and optimized its circuit constants by actual welding, and also improved a beam delivery system by optical fiber to obtain the optimum power density distribution at the focal point. Less