Positioner for cylindrical welded structure welding

Welding of longitudinal weld and outer girth weld of cylinder.There are mainly two kinds of welds on the cylindrical welding structure.One is the weld parallel to the cylinder axis,which is called longitudinal weld,and the other is the weld around the circumference of the cylinder,also known as girth weld.When the diameter of the cylinder is small,the single side welding and double-sided forming are generally adopted.When the cylinder diameter is large,the double-sided welding is generally used.Most of the pressure vessels used in petrochemical enterprises and boilers used in thermal power enterprises are relatively large in diameter,so the double-sided welding is basically adopted.

From the point of view of welding positioner method,the submerged arc welding is almost used in the welding of the cylinder at present,and the shielded metal arc welding is only used when the back cover welding or welding defect repair is required,and electroslag welding is generally used when the cylinder wall thickness is large.In addition,boilers and pressure vessels are equipment with explosion risk,which requires high welding quality.At the same time,local structure stress is relatively complex,and there are many kinds of steel products.Some steel products have poor weldability,and new technology and new technology are widely used.Therefore,the technical level of operators is required to be higher,and the requirements of welding procedures and management system are relatively strict.

For the welding of outer longitudinal seam and outer circumferential seam of cylinder,when submerged arc automatic welding is adopted,the cylinder body is generally placed on the roller carrier.When welding the outer longitudinal weld,the cylinder can be placed on the roller carrier and fixed.The tube welding positioner moves along the special track on the platform to complete the welding work at the welding speed;when welding the outer circumferential weld.The welding machine is fixed so that the cylinder can rotate and circle on the roller carrier at the welding speed to complete the welding work.In this way,we can design a platform type positioner,one is monorail positioner,the other is double track positioner.

During welding,the head of submerged arc welding machine is placed on the platform of positioner and fixed.The platform can move up and down along the column to adjust the distance between the welding machine and the weldment,and move along the track according to the welding speed to complete the welding work of longitudinal weld outside the cylinder.When welding the outer ring weld,the positioner is fixed,so the welding machine is fixed.The cylinder rotates on the roller frame under the platform to complete the welding work.The diameters of boilers and pressure vessels are large and small.In order to adapt to the welding of different diameter cylinders,cantilever positioner can also be designed.Compared with another pipe positioner,this positioner has greater flexibility.In addition to the same motion form,the welding head can move in a straight line along the cantilever arm,and the cantilever can be wound the column rotates.

Based on the welding process of boiler,pressure vessel and other cylindrical welding structures,based on the most of the submerged arc welding technology,this paper studies and designs the positioner which is suitable for the welding of longitudinal and circumferential welds inside and outside the cylinder,so that the boiler and pressure vessel manufacturing enterprises can greatly improve the welding production in the welding process efficiency,ensure joint quality, reduce labor intensity of workers.