VPPAW穿孔特性与焊缝成形稳定性的研究及控制
摘要
穿孔的稳定过渡是影响等离子焊缝成形的重要因素。基于其过程复杂、研究手段有限的特点,本文以温度场分布对过渡成形的影响为主要研究对象,实现穿孔稳定成形过程的控制。
通过穿孔过程分解研究,揭示出焊接工艺参数在小孔稳定建立过程中的影响规律。试验结果表明,焊接电流是影响穿孔加热速度及温度场分布的主要因素;离子气流量是影响穿孔挖掘速度及小孔形状的重要因素,并通过改变穿孔时间对加热过程施加影响;送丝时刻可改变穿孔成形,但对温度变化影响小。
鉴于穿孔过程的复杂性,起弧程序采用弱规范加热、强规范挖掘的控制策略,使穿孔加热过程与穿孔挖掘过程相对独立,达到降低控制难度,提高控制精度的目的。
在此基础上,通过控制起弧程序,确保穿孔时刻小孔周围的温度场分布接近优良焊缝的温度场分布,最终实现起弧的稳定成形。试验证实,穿孔时刻的温度场分布状态是影响起弧稳定成形的决定因素,其实质是保证穿孔时刻的熔池分别达到力和热的稳定平衡状态,小孔自稳定调节过程最短。
The stable transition of the keyhole weld pool in starting process seriously influences on the formation of weld during plasma arc welding. This keyhole establishing process is very complex and is not researched diffusely recently. By investigating the temperature field distribution’influence on the stable transition, as the main subject investigated, how to control the process parameters to complete the stable keyhole transition will be studied in this paper.
By analysis of the establishing process of the keyhole weld pool, the regularities of the welding parameters are obtained. The welding current mainly influences on the heating rate and the temperature distribution in the establishing of the keyhole. The plasma gas flow rate, which also affects the heating process by changing the occurrence time of the keyhole, can influences on the rate of excavating the keyhole and the geometrical size of the keyhole severely. The wire feed time can change the formation of weld in the starting process, but it doesn’t have any effect on the temperature.
Owing to the complexity of the keyhole establishing process, a new control mode, heating the weld pool by weak process parameters and excavating the keyhole by strong process parameters, is adopted. This control mode can reduce the difficulty of the control, improve the accuracy by making the heating process independent of the excavating process relatively.
Based on the above results, make sure the temperature filed distribution near the keyhole close to that near the satisfactory weld at the occurrence time of the keyhole by controlling the process parameters, the uniform formation of weld in the starting process is finished at last. The conclusion that the temperature fired distribution near the keyhole at the occurrence time of the keyhole is the decisive effect of the uniform formation of weld in starting process is proved. To keep the keyhole weld pool’s thermal and mechanical conditions balance respectively at the occurrence time of the keyhole, which aim is to shorten the keyhole’s self-regulating process seriously, is the essential of success.
通过穿孔过程分解研究,揭示出焊接工艺参数在小孔稳定建立过程中的影响规律。试验结果表明,焊接电流是影响穿孔加热速度及温度场分布的主要因素;离子气流量是影响穿孔挖掘速度及小孔形状的重要因素,并通过改变穿孔时间对加热过程施加影响;送丝时刻可改变穿孔成形,但对温度变化影响小。
鉴于穿孔过程的复杂性,起弧程序采用弱规范加热、强规范挖掘的控制策略,使穿孔加热过程与穿孔挖掘过程相对独立,达到降低控制难度,提高控制精度的目的。
在此基础上,通过控制起弧程序,确保穿孔时刻小孔周围的温度场分布接近优良焊缝的温度场分布,最终实现起弧的稳定成形。试验证实,穿孔时刻的温度场分布状态是影响起弧稳定成形的决定因素,其实质是保证穿孔时刻的熔池分别达到力和热的稳定平衡状态,小孔自稳定调节过程最短。
The stable transition of the keyhole weld pool in starting process seriously influences on the formation of weld during plasma arc welding. This keyhole establishing process is very complex and is not researched diffusely recently. By investigating the temperature field distribution’influence on the stable transition, as the main subject investigated, how to control the process parameters to complete the stable keyhole transition will be studied in this paper.
By analysis of the establishing process of the keyhole weld pool, the regularities of the welding parameters are obtained. The welding current mainly influences on the heating rate and the temperature distribution in the establishing of the keyhole. The plasma gas flow rate, which also affects the heating process by changing the occurrence time of the keyhole, can influences on the rate of excavating the keyhole and the geometrical size of the keyhole severely. The wire feed time can change the formation of weld in the starting process, but it doesn’t have any effect on the temperature.
Owing to the complexity of the keyhole establishing process, a new control mode, heating the weld pool by weak process parameters and excavating the keyhole by strong process parameters, is adopted. This control mode can reduce the difficulty of the control, improve the accuracy by making the heating process independent of the excavating process relatively.
Based on the above results, make sure the temperature filed distribution near the keyhole close to that near the satisfactory weld at the occurrence time of the keyhole by controlling the process parameters, the uniform formation of weld in the starting process is finished at last. The conclusion that the temperature fired distribution near the keyhole at the occurrence time of the keyhole is the decisive effect of the uniform formation of weld in starting process is proved. To keep the keyhole weld pool’s thermal and mechanical conditions balance respectively at the occurrence time of the keyhole, which aim is to shorten the keyhole’s self-regulating process seriously, is the essential of success.
引文
1 Philip Chien. Welding the Space Shuttle’s Al-Li External Tank Presents a Challenge. Welding Journal. 1998, 77(6): 45~47.
2 吕耀辉. 铝合金变极性穿孔型等离子弧焊接工艺的研究. 北京工业大学工学博士学位论文. 2003, 4: 2~5.
3 廖志谦, 王忠平. 钛合金厚板的等离子焊接. 材料开发于应用. 2005, 20(4): 27~28.
4 董春林, 吴林, 邵亦陈. 穿孔等离子弧焊发展历史与现状. 中国机械工程. 2000, 11(5): 577~581.
5 B.Zheng, H.J.Wang, Q.L.Wang, etc. Control for Weld Penetration in VPPAW of Aluminum Alloys Using the Front Weld Pool Image Signal. Welding Research Supplement. 2000, 12: 363~371.
6 Yu D Shchitsyn, V Yu Shchitsyn, H Herold, etc. Plasma welding of aluminium alloys. Welding International. 2003, 17(10): 825–832.
7 张修智. LYH12CZ 高强铝合金联合交流等离子弧焊接新工艺研究. 金属科学与工艺. 1985, (9): 111~116.
8 杨士勤, 董嵩申等. 交流等离子弧正极性焊铝的研究. 金属科学与工艺. 1985, 7: 108~114.
9 Kou S, Le Y. Improve Weld Quality by Low Frequentcy Arc Oscillation. Welding Journal. 1985, 64(3): 51~55.
10 M. J C, Qugley M B C. Keyhole Stability in Plasma Arc Welding. Welding Journal. 1975. 54(11): 401-s~404-s.
11 NASA. Fully Automated Variable Polarity Plasma Arc Welding. Research and Technology. 1992: 35~42.
12 Fuerschbach, P.W. Cathode Cleaning and Heat Input in Variable Polarity Plasma Arc Welding of Aluminum. Welding Journal. 1998, 77(2): 76~85.
13 J. Ding. Friction Stir Welding Process Development. MSFC Research and Technology Annual Report. Office of Aeronautics and Space Transportation Technology. 2000, (2): 13~19.
14 Nunes A C. Variable polarity plasma arc welding in space shuttle external tank. Welding Journal. 1984, 63(9): 27~35.
15 沈江红. 铝合金中厚板变极性等离子电弧焊焊接工艺的研究. 宇航材料工艺. 1997, (3): 46~54.
16 刘志华, 赵冰, 赵青. 21 世纪航天工业铝合金焊接工艺技术展望. 导弹与航天运载技术. 2002, (5): 2~4
17 吕耀辉, 陈树君, 殷树言. 铝合金变极性等离子弧焊接电源的研制. 航天制造技术. 2003, (1): 3~5.
18 Li Keqin, Shen Jianghong, Xie Feng, Hu Mingchen, Zhang Lingyun. Development of Variable Polarity Plasma Arc Welding Equipment. Aerospace Materials & Technology. 2002, (6): 39~42.
19 卢亚静, 胡绳荪, 易小林等. 小孔等离子弧焊接中小孔状态的传感技术研究. 电焊机. 2004, 34(2): 36~39.
20 杨春利, 林三宝. 电弧焊基础. 哈尔滨工业大学出版社. 2003, 2: 122~123.
21 雷玉成, 郑惠锦, 程晓农. 铝合金等离子立焊穿孔熔池的计算机模拟. 焊接学报. 2003, 24(1): 44~47
22 韩俭, 胡绳荪, 傅育文. 等离子弧焊接小孔行为检测方法概述. 电焊机. 2004, 34(4): 36~39.
23 Yaowen Wang, Qiang Chen. On-line quality monitoring in plasma-arc welding. Journal of Materials Processing Technology. 2002,120: 270~274.
24 Zhang.S.B, Zhang.Y.M. Efflux plasmacharge-based sensing and control of joint penetration during keyhole plasma are welding. Welding Journal. 2001, (7): 157~162.
25 Metcalfe.J.C. Automatic control of plasma welding utilizing the keyhole sfflux plasma. Welding and Metal Fabrication. 1975, (11): 674~677.
26 胡白喜, 黄从达. 利用声音信号进行脉冲等离子弧全位置焊接质量控制系统的研究. 焊接. 1984, (3): 10~14.
27 Emad Saad, Huijun Wang, Radovan Kovacevic. Classification of molten pool modes in variable polarity plasma arc welding based on acoustic signature. Journal of Materials Processing Technology. 2006, 174: 127~136.
28 Zhang.Y.M, Zhang.S.B, Liu.Y.C.A. Plasma cloud charge sensor for pulse keyhole process control. Measurement Science and Technology. 2001, (12): 1~6.
29 王海燕, 陈强, 王耀文等. 等离子焊接小孔效应的电弧电压信号检测. 清华大学学报. 2001, 41(8): 1~4.
30 王耀文, 陈强, 孙振国等. 等离子弧焊接穿孔行为的声信号传感. 机械工程学报. 2001, 37(1): 53~56.
31 Martinez L F, Marques R E, Mcclure J C. Front sidekeyhole detection in aluminum alloys. Welding Journal. 1971, (5): 49~51.
32 董春林, 朱轶峰, 吴 林. 穿孔等离子弧焊正面弧光传感技术研究. 机械工程学报. 2001, 37(3): 30~33.
33 刘中华. 视觉传感 VPPAW 焊缝成形实时控制系统. 哈尔滨工业大学博士学位论文. 2001, 12: 36~62.
34 Zhang Y M, Wu L, Walcott B L, etc. Determining joint penetration in GTAW with vision sensing of weld face geometry. Welding Journal. 1993, 72(10): 463s~469s
35 代大山, 宋永伦, 江 伟. 小孔等离子弧焊接质量控制的研究概况及发展. 焊接技术. 2000, 29(6): 2~4.
36 Hsu Y F, Rubinsky B. Two-dimensional heat transfer study on the key hole plasma arc process. Heat Mass Transfer. 1988, 31(7):1409~1421.
37 Russell G, Keanini, Boris Rubinsky. Three-dimensional simulation of the plasma arc welding process. Heat Mass Transfer. 1993, 36(13): 3283~3298.
38 董红刚, 高洪明, 吴林. 固定电弧等离子弧焊接热传导的数值计算. 焊接学报. 2002, 23(4): 24~26.
39 陈焕明, 江淑园, 谢美蓉. 穿孔等离子弧焊熔池形成过程的仿真. 科技成果学术论文. 2003, (7): 28~30, 74
40 王怀刚, 武传松, 张明贤. 小孔等离子弧焊接热场的有限元分析. 焊接学报. 2005, 26(7): 49~53.
41 薛德涛. 铝合金等离子弧立焊小孔动态稳定性研究. 哈尔滨工业大学硕士学位论文. 1991, 3: 43~46.
42 王祝堂, 田荣璋. 铝合金及其加工手册. 第二版. 中南大学出版社, 2000: 803, 808.
43 王振琪, 吴晓明, 杨一平. 物理化学. 化学工业出版社, 2002: 253~254.
44 雷玉成, 郑惠锦. 穿孔法等离子弧立焊焊缝成形机理初探. 江苏理工大学学报(自然科学版). 2000, (1):61~64.
2 吕耀辉. 铝合金变极性穿孔型等离子弧焊接工艺的研究. 北京工业大学工学博士学位论文. 2003, 4: 2~5.
3 廖志谦, 王忠平. 钛合金厚板的等离子焊接. 材料开发于应用. 2005, 20(4): 27~28.
4 董春林, 吴林, 邵亦陈. 穿孔等离子弧焊发展历史与现状. 中国机械工程. 2000, 11(5): 577~581.
5 B.Zheng, H.J.Wang, Q.L.Wang, etc. Control for Weld Penetration in VPPAW of Aluminum Alloys Using the Front Weld Pool Image Signal. Welding Research Supplement. 2000, 12: 363~371.
6 Yu D Shchitsyn, V Yu Shchitsyn, H Herold, etc. Plasma welding of aluminium alloys. Welding International. 2003, 17(10): 825–832.
7 张修智. LYH12CZ 高强铝合金联合交流等离子弧焊接新工艺研究. 金属科学与工艺. 1985, (9): 111~116.
8 杨士勤, 董嵩申等. 交流等离子弧正极性焊铝的研究. 金属科学与工艺. 1985, 7: 108~114.
9 Kou S, Le Y. Improve Weld Quality by Low Frequentcy Arc Oscillation. Welding Journal. 1985, 64(3): 51~55.
10 M. J C, Qugley M B C. Keyhole Stability in Plasma Arc Welding. Welding Journal. 1975. 54(11): 401-s~404-s.
11 NASA. Fully Automated Variable Polarity Plasma Arc Welding. Research and Technology. 1992: 35~42.
12 Fuerschbach, P.W. Cathode Cleaning and Heat Input in Variable Polarity Plasma Arc Welding of Aluminum. Welding Journal. 1998, 77(2): 76~85.
13 J. Ding. Friction Stir Welding Process Development. MSFC Research and Technology Annual Report. Office of Aeronautics and Space Transportation Technology. 2000, (2): 13~19.
14 Nunes A C. Variable polarity plasma arc welding in space shuttle external tank. Welding Journal. 1984, 63(9): 27~35.
15 沈江红. 铝合金中厚板变极性等离子电弧焊焊接工艺的研究. 宇航材料工艺. 1997, (3): 46~54.
16 刘志华, 赵冰, 赵青. 21 世纪航天工业铝合金焊接工艺技术展望. 导弹与航天运载技术. 2002, (5): 2~4
17 吕耀辉, 陈树君, 殷树言. 铝合金变极性等离子弧焊接电源的研制. 航天制造技术. 2003, (1): 3~5.
18 Li Keqin, Shen Jianghong, Xie Feng, Hu Mingchen, Zhang Lingyun. Development of Variable Polarity Plasma Arc Welding Equipment. Aerospace Materials & Technology. 2002, (6): 39~42.
19 卢亚静, 胡绳荪, 易小林等. 小孔等离子弧焊接中小孔状态的传感技术研究. 电焊机. 2004, 34(2): 36~39.
20 杨春利, 林三宝. 电弧焊基础. 哈尔滨工业大学出版社. 2003, 2: 122~123.
21 雷玉成, 郑惠锦, 程晓农. 铝合金等离子立焊穿孔熔池的计算机模拟. 焊接学报. 2003, 24(1): 44~47
22 韩俭, 胡绳荪, 傅育文. 等离子弧焊接小孔行为检测方法概述. 电焊机. 2004, 34(4): 36~39.
23 Yaowen Wang, Qiang Chen. On-line quality monitoring in plasma-arc welding. Journal of Materials Processing Technology. 2002,120: 270~274.
24 Zhang.S.B, Zhang.Y.M. Efflux plasmacharge-based sensing and control of joint penetration during keyhole plasma are welding. Welding Journal. 2001, (7): 157~162.
25 Metcalfe.J.C. Automatic control of plasma welding utilizing the keyhole sfflux plasma. Welding and Metal Fabrication. 1975, (11): 674~677.
26 胡白喜, 黄从达. 利用声音信号进行脉冲等离子弧全位置焊接质量控制系统的研究. 焊接. 1984, (3): 10~14.
27 Emad Saad, Huijun Wang, Radovan Kovacevic. Classification of molten pool modes in variable polarity plasma arc welding based on acoustic signature. Journal of Materials Processing Technology. 2006, 174: 127~136.
28 Zhang.Y.M, Zhang.S.B, Liu.Y.C.A. Plasma cloud charge sensor for pulse keyhole process control. Measurement Science and Technology. 2001, (12): 1~6.
29 王海燕, 陈强, 王耀文等. 等离子焊接小孔效应的电弧电压信号检测. 清华大学学报. 2001, 41(8): 1~4.
30 王耀文, 陈强, 孙振国等. 等离子弧焊接穿孔行为的声信号传感. 机械工程学报. 2001, 37(1): 53~56.
31 Martinez L F, Marques R E, Mcclure J C. Front sidekeyhole detection in aluminum alloys. Welding Journal. 1971, (5): 49~51.
32 董春林, 朱轶峰, 吴 林. 穿孔等离子弧焊正面弧光传感技术研究. 机械工程学报. 2001, 37(3): 30~33.
33 刘中华. 视觉传感 VPPAW 焊缝成形实时控制系统. 哈尔滨工业大学博士学位论文. 2001, 12: 36~62.
34 Zhang Y M, Wu L, Walcott B L, etc. Determining joint penetration in GTAW with vision sensing of weld face geometry. Welding Journal. 1993, 72(10): 463s~469s
35 代大山, 宋永伦, 江 伟. 小孔等离子弧焊接质量控制的研究概况及发展. 焊接技术. 2000, 29(6): 2~4.
36 Hsu Y F, Rubinsky B. Two-dimensional heat transfer study on the key hole plasma arc process. Heat Mass Transfer. 1988, 31(7):1409~1421.
37 Russell G, Keanini, Boris Rubinsky. Three-dimensional simulation of the plasma arc welding process. Heat Mass Transfer. 1993, 36(13): 3283~3298.
38 董红刚, 高洪明, 吴林. 固定电弧等离子弧焊接热传导的数值计算. 焊接学报. 2002, 23(4): 24~26.
39 陈焕明, 江淑园, 谢美蓉. 穿孔等离子弧焊熔池形成过程的仿真. 科技成果学术论文. 2003, (7): 28~30, 74
40 王怀刚, 武传松, 张明贤. 小孔等离子弧焊接热场的有限元分析. 焊接学报. 2005, 26(7): 49~53.
41 薛德涛. 铝合金等离子弧立焊小孔动态稳定性研究. 哈尔滨工业大学硕士学位论文. 1991, 3: 43~46.
42 王祝堂, 田荣璋. 铝合金及其加工手册. 第二版. 中南大学出版社, 2000: 803, 808.
43 王振琪, 吴晓明, 杨一平. 物理化学. 化学工业出版社, 2002: 253~254.
44 雷玉成, 郑惠锦. 穿孔法等离子弧立焊焊缝成形机理初探. 江苏理工大学学报(自然科学版). 2000, (1):61~64.