等离子弧焊小孔电压与规范参数的关系初探

Three Calculation Formulas to Help ImplementEffective Adaptive Control for Producing HighQuality KeyholeMode Plasma Arc Weld

对小孔法等离子弧焊小孔电压与离子气流量、焊接速度及焊接电流的关系进行了初步探讨。对实际焊接过程中所测数据，利用逐步回归分析法进行了处理，得出了相应的数学关系式。

In adaptive control of keyholemode plasma arc welding (PAW), trial and error procedure has been still unavoidable and has impeded the widening of its application. I worked out three formulas that could make trialanderror procedure unnecessary. The said three calculation formulas were obtained with methods that were known but were, to my best knowledge, never employed in connection with PAW control. Specifically experimental measurement of keyhole voltage while actual PAW was proceeding was known and stepbystep regression was likewise known. But in the past, PAW researchers preferred to measure keyhole voltage with other methods that appeared to me to be less satisfactory. Eqs.(16),(17),and (18) give keyhole voltage in terms of v (welding speed), Q Ⅱ (flow of plasma gas), and I (welding current) respectively. The designer may select any one of the three formulas that he feels to be most convenient for implementing his control design. Fig.2 shows the highquality keyholemode plasma arc weld obtained with adaptive control which was implemented with the help of eq.(18). The circumferential plasma arc weld, 10 mm in thickness, and 100 mm in inside diameter, did not require previous beveling of the edge to be cut and welding it once only gave a completely satisfactory weld.