LNG储罐用9%Ni钢自动立缝焊接系统设计

发布时间：2018-08-11 13:33

【摘要】：伴随着全球液化天然气(Liquefied natural gas,简称LNG)消耗量持续增长,低温韧性优良的9%Ni钢成为建造LNG低温储罐的主要用材。9%Ni钢在LNG储罐壁板立缝焊接作为储罐建造的重要焊接工序,目前,主要采用手工焊,这种焊接效率低,劳动条件差,强度高,焊接质量不易保证,故研究出方便简单、高效快速、焊接质量优质的LNG储罐用9%Ni钢自动立缝焊接系统成为了首要任务。首先,本文根据自动立缝焊机方案设计要求,对焊接用材9%Ni钢焊接性能进行分析,提出了合理的焊接工艺及焊接方法,并设计了基值与峰值电流可调节的脉冲焊;摆动器可实现焊枪摆动控制和氩弧脉冲电流同频、同相、同脉宽的控制方式;热丝电流输入值通过建立热丝控制模型,实现PID控制算法对热丝电流输入值的控制;弧压调高根据弧压与弧长的关系,实现了可变增益的PID弧长跟踪控制算法;通过PI算法实现送丝电机的稳定送丝等控制策略,并根据焊接策略控制要求设计焊接设备的机械结构。然后,根据焊控工艺及控制要求,对硬件电路选型,设计了一套基于西门子S7-1200 PLC控制器的自动立缝弧焊专机控制系统。并对焊接流程及脉冲焊、摆动器摆动、热丝电流输入值、弧压调高、稳定送丝等功能进行了软件设计。该系统控制台面板上放置触摸屏及操作按钮,系统能实现对外部信号的采集、人机对话,设定参数、显示焊接时序、运动状态,并基于PAC的Indu Soft组态软件,对焊接在线监测系统进行开发,完成PAC与S7-1200 PLC的通讯,实现焊接成本管理、数据管理、设备管理、人员管理、品质管理。最后,通过现场试验及客户使用表明,PLC控制系统硬件抗干扰能力强、维护简单、可靠性提高,软件能满足焊接工艺过程控制要求,焊缝质量检测合格。整个系统实现了LNG储罐用9%Ni钢自动立缝焊接系统在焊接工艺过程的机械化、自动化控制。
[Abstract]:With the increasing consumption of global liquefied natural gas (Liquefied natural gas,) for short (LNG), 9%Ni steel with good low temperature toughness has become the main material for building LNG low temperature storage tank. The vertical seam welding of LNG storage tank wall plate is an important welding procedure. At present, Manual welding is mainly used. The welding efficiency is low, the working conditions are poor, the strength is high, the welding quality is not easy to guarantee, so the research is convenient, simple, efficient and fast. The automatic vertical seam welding system of 9%Ni steel for LNG storage tank with high welding quality has become the primary task. Firstly, according to the design requirements of automatic vertical seam welding machine, the welding performance of 9%Ni steel is analyzed, the reasonable welding process and welding method are put forward, and the pulse welding with adjustable base value and peak current is designed. The wiggler can realize the control of welding torch swing and argon arc pulse current in the same frequency, same phase and same pulse width, and the hot wire current input value can be controlled by PID control algorithm by establishing the hot wire control model. According to the relationship between arc voltage and arc length, the variable gain PID arc length tracking control algorithm is realized, and the stable wire feeding strategy of wire feeder motor is realized by Pi algorithm. The mechanical structure of welding equipment is designed according to the requirements of welding strategy control. Then, according to welding control technology and control requirements, a set of automatic vertical arc welding machine control system based on Siemens S7-1200 PLC controller is designed for hardware circuit selection. The software design of welding process, pulse welding, swing of swinging device, input value of hot wire current, adjustment of arc voltage, stable wire feeding and so on are carried out. The system controls the display of touch screen and operation button on the counter board. The system can realize the acquisition of external signals, man-machine dialogue, setting parameters, displaying welding timing, moving state, and Indu Soft configuration software based on PAC. The welding on-line monitoring system is developed, the communication between PAC and S7-1200 PLC is completed, and welding cost management, data management, equipment management, personnel management and quality management are realized. Finally, through field test and customer usage, it is shown that PLC control system has strong hardware anti-interference ability, simple maintenance, improved reliability, the software can meet the requirements of welding process control, and the weld quality inspection is qualified. The whole system realizes the mechanization and automation control of 9%Ni steel automatic vertical seam welding system in the welding process of LNG storage tank.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TE972;TG457.11

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