{"title":"Improving current window in keyhole welding with double-layers hybrid arc heat source","authors":"ZuMing Liu , BoHan Jia , XuMin Guo , XingChuan Zhao","doi":"10.1016/j.jmatprotec.2024.118646","DOIUrl":null,"url":null,"abstract":"<div><div>Keyhole welding can be easily achieved with a plasma arc, but the process window is narrow because too high arc pressure will damage the keyhole stability. Double-layers hybrid arc heat source was developed by compositing an outer layer of free arc into the center plasma arc jet, the arc heat power can be adjusted in wide range with suppression of arc pressure changing. Keyhole stability was tested to be improved with 6mm-thick stainless steel in previous works, but the stability principle is not yet discussed. In this paper, keyhole welding tests were carried out with thicker steel plates to evaluate the usable welding current window improvement and the weld pool stabilization principle. Results show that the usable current window with the hybrid arc is nearly double wider over that with plasma arc in the 6mm-, 8mm- and 16mm-thick plates. The added free arc heat is deposited into the keyhole bottom with limited ratio, the backside weld width increases much more (about 2.4–6 folders) slowly by increasing the free arc current than by increasing the plasma arc current. Keyhole weld pool stabilization principle is outlined: if the plasma arc is given, arc pressure is almost fixed, surface tension in backside weld surface decreases slowly with the free arc current, weld pool force balance can be achieved in much wider range of welding current. Smooth front and backside weld surfaces are easily obtained with hybrid arc. The research indicates that, for application of the developed hybrid arc system in keyhole welding field, the plasma arc should get the fully penetration threshold, the free arc current is used as the process adjuster, the usable welding current range is very wide.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"334 ","pages":"Article 118646"},"PeriodicalIF":6.7000,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Materials Processing Technology","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0924013624003649","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, INDUSTRIAL","Score":null,"Total":0}
引用次数: 0
Abstract
Keyhole welding can be easily achieved with a plasma arc, but the process window is narrow because too high arc pressure will damage the keyhole stability. Double-layers hybrid arc heat source was developed by compositing an outer layer of free arc into the center plasma arc jet, the arc heat power can be adjusted in wide range with suppression of arc pressure changing. Keyhole stability was tested to be improved with 6mm-thick stainless steel in previous works, but the stability principle is not yet discussed. In this paper, keyhole welding tests were carried out with thicker steel plates to evaluate the usable welding current window improvement and the weld pool stabilization principle. Results show that the usable current window with the hybrid arc is nearly double wider over that with plasma arc in the 6mm-, 8mm- and 16mm-thick plates. The added free arc heat is deposited into the keyhole bottom with limited ratio, the backside weld width increases much more (about 2.4–6 folders) slowly by increasing the free arc current than by increasing the plasma arc current. Keyhole weld pool stabilization principle is outlined: if the plasma arc is given, arc pressure is almost fixed, surface tension in backside weld surface decreases slowly with the free arc current, weld pool force balance can be achieved in much wider range of welding current. Smooth front and backside weld surfaces are easily obtained with hybrid arc. The research indicates that, for application of the developed hybrid arc system in keyhole welding field, the plasma arc should get the fully penetration threshold, the free arc current is used as the process adjuster, the usable welding current range is very wide.
期刊介绍:
The Journal of Materials Processing Technology covers the processing techniques used in manufacturing components from metals and other materials. The journal aims to publish full research papers of original, significant and rigorous work and so to contribute to increased production efficiency and improved component performance.
Areas of interest to the journal include:
• Casting, forming and machining
• Additive processing and joining technologies
• The evolution of material properties under the specific conditions met in manufacturing processes
• Surface engineering when it relates specifically to a manufacturing process
• Design and behavior of equipment and tools.