摘要:
应用具有自由表面的流体稳定性理论,分析了焊接熔池失稳的产生机理,并对双丝共熔池MAG焊接脉冲电流不同相位关系对焊缝成形的影响进行了试验观察与分析.结果表明,双丝脉冲电流为同步相位时,电弧周期性的熄灭可以减少对熔池的加热量,防止熔池过长而失稳.双丝脉冲电流为交替相位关系时,主机与从机电弧交替出现,使熔池始终处于电弧的加热之下,热输入量大,熔化态金属的长度较长,产生驼峰焊道的可能性加大.双丝脉冲电流为随机相位时,主机、从机焊丝电弧时而同步燃烧或同步熄灭,时而交替燃烧与熄灭;同步熄灭时,熔池可及时冷却,交替燃烧与熄灭时,熔池始终处于电弧的加热之下,熔池难以及时冷却,因此焊缝表面不均匀.
Abstract:
The theory of stability of a liquid with free surface was applied to understand the instability phenomenon in bead formation.The experiment and analysis were carried out to discuss the effects on the bead formation for different current phases.The result showed that with the pulse current of the host and the accessory changed synchronously,the twin arc extinguished periodically.Then the heat which was transferred into the molten pool was decreased.This helped to avoid the molten pool to be too long and avoided the unstability of the liquid metal.When the pulse current of the host and the accessory changed alternately,the workpiece was heated by the arc throughout the welding process.As a result,the molten pool was very long,which gave way to the unstability of bead formation and pinch effect of the liquid metal,so that it finally leaded to the humping phenomenon.When the pulse current phase of the host and the accessory changed indefinitely,the arc burned and extinguished in random.At the same time,the twin arc extinguished and the molten pool solidified in time.But when the twin arc extinguished,the molten pool could solidify in time and an uneven weld appearance was formed.
百度学术
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