ようこそ ゲスト さん
雑誌ブラウズ
雑誌 全て
大阪大学 刊行物
ランキング
アクセスランキング
ダウンロードランキング
博士論文のみをさがす
このアイテムのアクセス数:
52
件
(
2021-04-18
17:12 集計
)
このアイテムへのリンクには次のURLをご利用ください:http://hdl.handle.net/11094/6896
閲覧可能ファイル
ファイル
フォーマット
サイズ
閲覧回数
説明
jwri40_01_025
pdf
396 KB
67
論文情報
タイトル
Numerical Model of Gas Metal Arc with Metal Vapor for Heat Source in Welding
著者
Tsujimura, Yoshihiro
Tsujimura, Yoshihiro
Tashiro, Shinichi
Tashiro, Shinichi
Tanaka, Manabu
Tanaka, Manabu
キーワード等
GMA welding
Metal vapor
Simulation
抄録
In gas metal arc (GMA) welding, an arc discharge is applied for melting and joining metals. An electric arc is established between a base metal cathode and a consumable wire anode. By the high heat flux from the arc plasma, a droplet forms at the tip of wire and a weld pool forms at the base metal. Arc plasma is composed of large amounts of metal vapor from the droplet and the weld pool. From past studies, it is known that a mixture of metal vapor affects the properties of the arc plasma, such as electrical conductivity and radiative emission coefficient. Numerical models need many assumptions and time for complicated calculations. Therefore, to reduce assumptions and calculation time, a simplified model of the GMA welding arcs ignoring metal transfer is built. In the present model, special account is taken of the amounts of metal vapor, enthalpy of droplet and wire melting rate. These are calculated simultaneously. And then, the present model assumes a steady state, and that arc length is constant. Therefore, the wire feed rate is equal to the calculated wire melting rate. And then, the wire feed rate and the wire melting rate are balanced to keep arc length constant. We study the effects of metal vapor on the heat source properties of GMA welding arcs by using this model. The calculated mole fraction distribution is in agreement with the observed optical image separating bright regions at the arc center, dominated by the metal vapor, and dark regions at the outer arc. The highest temperatures occur at the edge of the arc core. Higher welding currents lead to faster melting and feed rates of consumable wire because of larger heat inputs, such as thermal conduction from the arc plasma and ohmic heating at the wire. For balance of larger heat inputs and faster feed rates of the wire, temperatures of the tip of wire, namely droplet, are kept constant though higher welding currents. This result is experimentally known, however this model enable it to be understood as a physical phenomenon.
公開者
大阪大学接合科学研究所
公開者の別表記
Joining and Welding Research Institute, Osaka University
公開者 (ヨミ)
オオサカ ダイガク セツゴウ カガク ケンキュウジョ
掲載誌名
Transactions of JWRI
巻
40
号
1
開始ページ
25
終了ページ
29
刊行年月
2011-06
ISSN
03874508
NCID
AA00867058
URL
http://hdl.handle.net/11094/6896
言語
英語
カテゴリ
紀要論文 Departmental Bulletin Paper
Transactions of JWRI / Vol.40 No.1 (2011-06)
論文詳細を表示
著者版フラグ
publisher
NII資源タイプ
紀要論文
ローカル資源タイプ
紀要論文
dcmi資源タイプ
text
DCTERMS.bibliographicCitation
Transactions of JWRI.40(1) P.25-P.29
DC.title
Numerical Model of Gas Metal Arc with Metal Vapor for Heat Source in Welding
DC.creator
Tsujimura, Yoshihiro
Tashiro, Shinichi
Tanaka, Manabu
DC.publisher
大阪大学接合科学研究所
DC.language" scheme="DCTERMS.RFC1766
英語
DCTERMS.issued" scheme="DCTERMS.W3CDTF
2011-06
DC.identifier" scheme="DCTERMS.URI
http://hdl.handle.net/11094/6896
DC.subject
GMA welding
Metal vapor
Simulation
DCTERMS.abstract
In gas metal arc (GMA) welding, an arc discharge is applied for melting and joining metals. An electric arc is established between a base metal cathode and a consumable wire anode. By the high heat flux from the arc plasma, a droplet forms at the tip of wire and a weld pool forms at the base metal. Arc plasma is composed of large amounts of metal vapor from the droplet and the weld pool. From past studies, it is known that a mixture of metal vapor affects the properties of the arc plasma, such as electrical conductivity and radiative emission coefficient. Numerical models need many assumptions and time for complicated calculations. Therefore, to reduce assumptions and calculation time, a simplified model of the GMA welding arcs ignoring metal transfer is built. In the present model, special account is taken of the amounts of metal vapor, enthalpy of droplet and wire melting rate. These are calculated simultaneously. And then, the present model assumes a steady state, and that arc length is constant. Therefore, the wire feed rate is equal to the calculated wire melting rate. And then, the wire feed rate and the wire melting rate are balanced to keep arc length constant. We study the effects of metal vapor on the heat source properties of GMA welding arcs by using this model. The calculated mole fraction distribution is in agreement with the observed optical image separating bright regions at the arc center, dominated by the metal vapor, and dark regions at the outer arc. The highest temperatures occur at the edge of the arc core. Higher welding currents lead to faster melting and feed rates of consumable wire because of larger heat inputs, such as thermal conduction from the arc plasma and ohmic heating at the wire. For balance of larger heat inputs and faster feed rates of the wire, temperatures of the tip of wire, namely droplet, are kept constant though higher welding currents. This result is experimentally known, however this model enable it to be understood as a physical phenomenon.
citation_title
Numerical Model of Gas Metal Arc with Metal Vapor for Heat Source in Welding
citation_author
Tsujimura, Yoshihiro
Tashiro, Shinichi
Tanaka, Manabu
citation_publisher
大阪大学接合科学研究所
citation_language
英語
citation_date
2011-06
citation_journal_title
Transactions of JWRI
citation_volume
40
citation_issue
1
citation_firstpage
25
citation_lastpage
29
citation_issn
03874508
citation_public_url
http://hdl.handle.net/11094/6896
citation_keywords
GMA welding
Metal vapor
Simulation