Automated Straight Seam Welding System for Shell Courses, LT-MZ1222 Column & Boom Manipulator for Full-Length Longitudinal Welds

In the manufacturing of storage tanks, pressure vessels, boiler barrels and large cylindrical steel structures, longitudinal straight seam welding is the most critical primary welding process. The long straight welds on rolled shell courses directly determine the overall structural rigidity, pressure bearing capacity, sealing performance and safety service life of finished cylindrical equipment.

Traditional manual longitudinal seam welding has inherent technical defects. When welding long-distance straight seams, manual operation cannot maintain constant walking speed, stable arc length and uniform heat input. It easily causes weld track deviation, uneven penetration, wavy weld beads, undercut, porosity, slag inclusion and local incomplete fusion. These defects lead to low product qualification rate, massive polishing and rework, long production cycles and extreme dependence on highly skilled welders, which seriously restricts standardized mass production of tank and pressure vessel workshops.

The LT-MZ1222 Automatic Column & Boom Welding Manipulator is industrially customized for high-precision longitudinal straight seam welding of large rolled steel plates and shell courses. Different from circumferential welding mode, this equipment adopts a workpiece fixed + welding torch mobile precision linear welding technology. The welding boom travels steadily and linearly across the full length of the weld seam, achieving constant speed, fixed track and uniform heat input throughout the whole welding process. Cooperated with welding turning rolls to fix cylindrical shell plates, it builds a professional automated longitudinal seam welding workstation.

The equipment fully supports submerged arc welding (SAW), CO₂ gas shielded welding and MIG/MAG welding processes. It is suitable for mass welding of carbon steel, stainless steel and low alloy steel plates. It is widely used in large tank factories, pressure vessel manufacturing workshops, boiler processing plants and cylindrical steel structure production enterprises. The machine can freely switch to circumferential girth welding mode to realize dual-process integrated production.

Longitudinal seam welding for shell courses requires an extremely straight welding track and consistent thermal penetration effect. This manipulator adopts an industrial standardized linear automatic welding principle, with stable and repeatable welding logic:

1. Workpiece Fixed Positioning — Place the rolled tank shell course or flat cylinder steel plate on heavy-duty welding turning rolls. The turning rolls lock the workpiece position to ensure no shaking, displacement or rotation during longitudinal welding, providing a stable welding foundation.
2. Precision Torch Alignment — Adjust the vertical column height and boom extension distance, and fine-tune the welding torch through an XYZ three-dimensional micro-adjustment mechanism to accurately center the weld groove, compensating for plate assembly errors and groove deviation.
3. Parameter Intelligent Setting — Set precise welding current, voltage, travelling speed and arc length compensation through the PLC touch screen system according to plate thickness, material and groove type.
4. Full-Stroke Constant-Speed Linear Welding — The horizontal boom drives the welding torch to move horizontally and linearly at a constant preset speed, travelling through the full length of the longitudinal seam. The whole process realizes stable arc burning, uniform heat input and consistent penetration.
5. One-Time Continuous Weld Forming — Complete uninterrupted full-length straight seam welding, forming flat, dense, uniform and defect-free longitudinal welds that fully meet NDT non-destructive testing standards.

For circumferential welding production of pipe fittings and barrel ring seams, the equipment can switch the working mode: the workpiece rotates at a constant speed, and the welding torch is fixed, realizing high-precision girth seam welding.

The vertical main column is made of thickened national standard steel plates through integral full welding and secondary vibration aging stress relief treatment. The overall structure has ultra-high rigidity, strong anti-deformation ability and zero shaking during full-stroke long-distance movement. It completely avoids welding track deviation caused by frame vibration and ensures ultra-stable support for long-seam precision welding.

Closed rectangular high-strength boom structure with optimized anti-bending and anti-torsion mechanical design. The horizontal travelling guide rail is precision-machined, with smooth operation, uniform feeding speed and no jitter. It guarantees a straight and consistent welding track for ultra-long longitudinal seams.

Adopts industrial motor and precision gear-rack transmission structure. The lifting action is stable, silent and highly accurate. It can fine-adjust the torch height in real time according to different plate thicknesses, multi-layer welding layers and groove depths to ensure optimal arc ignition position and penetration effect.

Horizontal travelling speed adopts frequency conversion stepless adjustable design. Operators can scientifically match the travelling speed according to steel material, plate thickness and welding process requirements, realizing precise control of welding heat input and improving weld density and toughness.

Equipped with X, Y, Z three-direction manual micro-adjustment function. For uneven assembly gaps, plate misalignment and multi-layer multi-pass welding, the torch position can be accurately fine-tuned to always align with the weld centerline, effectively eliminating welding deviation defects.

Industrial dedicated PLC core control + high-definition human-machine touch screen interface. It supports real-time parameter modification, multi-group welding process recipe storage, one-key saving and fast recall. It can preset standard parameters for common shell plate specifications, realizing rapid switching of different products and continuous batch automated production.

All power cables, signal control lines and air pressure pipelines are fully built into high-strength industrial drag chains. It effectively prevents cable stretching, extrusion, friction damage and aging during long-term reciprocating movement, greatly improving equipment stability and overall service life.

Equipped with upper and lower lifting limit protection, front and rear travelling limit protection, emergency stop button and mechanical anti-collision device. It completely avoids equipment overtravel, collision failure and workshop safety accidents, fully complying with heavy industrial safety operation specifications.

The constant-speed linear travelling system ensures consistent arc length, stable heat input and uniform penetration from the starting point to the ending point of the longitudinal seam. The weld surface is flat and smooth, with dense internal structure, no undercut, no porosity and no slag inclusion. The one-time pass rate is extremely high, fully meeting pressure vessel and tank NDT testing standards.

Aiming at the production characteristics of large-size and long-seam rolled shell plates, it solves the industry pain point of unstable quality and difficult standardization of manual long-seam welding, greatly improving the qualification rate of cylinder blank rolling and forming processes.

Preset standard welding recipes for conventional plate thicknesses and seam lengths. No repeated mechanical debugging and parameter calibration are required during order switching, greatly reducing setup time and enabling continuous automated production.