PDF《埋弧自动焊》

3 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 ? 焊缝必须是直的 ? 焊缝必须干净,事先用砂轮打磨 ? 焊丝的位置非常重要 ? 焊剂应该覆盖整个电弧 ? 焊剂应该干燥 焊接过程中需要注意的问题 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 ? There are several ways to increase productivity further, relative to single wire only: C Twin-arc: Welding with two wires and one power source. C Tandem: Welding with two wires and two power sources. C Grain: Welding with the addition of metal powder. C Cold wire: Welding with the addition of cold wire. 生产率的比较 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 DC power source + - Twin - arc welding Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 A6S W/Twin Arc Kit A6 Twin arc Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 AC power source DC power source + - Direction of welding ~

30 mm Tandem arc Welding Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 Single pool - Highest deposition rate Twin pool - Travel speed limited by undercut Very resistant to porosity and cracks Tandem arc Welding

4 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 A6 Tandem Subarc Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 ? 提高焊接速度和熔敷率 ? 降低降低母材金属的稀释率,获得较高的冲击强 度Iron Powder feed unit Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 Iron Powder Feed Unit Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 ? 1,6 ? 2,0 ? 2,5 ? 3,2 ? 4,0 ? 5,0 ? 6,0

200 400

600 800

1000 1200 Ampere 9,0 kg/h 10,3 kg/h 9,5 kg/h 11,4 kg/h 10,6 kg/h 18,8 kg/h 21,8 kg/h 2,7 kg/h 3,8 kg/h 3,5 kg/h 3,4 kg/h 4,6 kg/h 5,7 kg/h 5,6 kg/h SAW的熔敷率 ? 对于不同直径的焊丝,推荐的电流和熔敷率 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 kg/m Welding speed in m/h 0,4 0,3

0 0,1 0,2

40 80

60 100

160 140

120 焊剂的消耗 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 ? Higher amperage gives deeper penetration Higher voltage gives wider penetration. The arc length gets extended. 焊接电流和电弧电压的影响

5 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 ? Longer stick-out gives higher deposition rate, but also more shallow penetration. ? Above: Penetration at different stick-out ? Right: Deposition rate at different stick-outs. A:

25 mm B:

57 mm C:

83 mm 干伸长的影响 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 ? Deepest penetration with positive electrode. Normally, the welding machine is equipped with DC positive electrode. ? At constant amperage, the penetration gets deeper with smaller wire diameter, due to the higher current density. 极性和焊丝直径 Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 Backhand Vertical Forehand ? The wire angle influences both penetration, the weld convexity, and the tendency to undercutting. ? Backhand gives high penetration, narrow and high weld convexity, and relatively high risk for undercutting. ? Vertical welding gives normal values. ? Forehand gives low penetration, wide and low weld convexity, and relatively slight risk for undercutting. Influence of wire angle Copyright ? 2006, 林三宝 http://weld.hit.edu.cn 现代焊接生产技术国家重点实验室 Root defect Examples of incorrect weld joints ? Welding with too high current and / or too slow speed, results in an incorrect cross - section. There is a big risk for cracking. ? Too high voltage can cause an incomplete penetration ........