Processing of steel for tubular trusses

Pipe truss processing is a complex and meticulous task, widely used in various large-scale building structures. The following provides a detailed explanation from the aspects of material preparation, processing procedures, and quality control:

1. Material Preparation: Based on design requirements, accurately procure standard-compliant pipes, commonly including Q235B, Q355B, etc., ensuring that material certifications and inspection reports are complete. Conduct visual inspections of the procured pipes to check for defects such as cracks, dents, and corrosion. Simultaneously, use measuring tools to verify whether the pipe dimensions, such as diameter and wall thickness, meet the standards.

2. Processing Procedures

• Cutting and Blanking: According to the length specified in the design drawings, use equipment such as CNC cutting machines and sawing machines to cut the pipes, ensuring that the cut ends are smooth and perpendicular to the pipe axis, with errors controlled within the allowable range.

• Intersecting Line Processing: Pipes at the nodes of the truss require intersecting line cutting. Using CNC intersecting line cutting machines, input precise 3D model data to cut accurate intersecting line shapes, ensuring the connection accuracy of the pipes at the nodes.

• Pipe Bending: For pipe sections requiring curvature, use professional pipe bending equipment for processing. During the bending process, strictly control the bending radius and angle, employing medium-frequency heating bending technology to ensure that the pipes do not develop wrinkles, cracks, or other issues during bending.

• Assembly and Welding: On the assembly platform, assemble the cut and processed pipes according to the design drawings. Use positioning fixtures and clamps to ensure the accurate relative positions of the members. Employ welding methods such as CO₂ gas shielded welding and manual arc welding. During welding, strictly control parameters such as welding current, voltage, and welding speed.

• Surface Treatment: After welding is completed, perform surface treatment on the pipe truss to remove impurities such as welding slag, spatter, and corrosion. Use shot blasting for derusting to achieve a Sa2.5-grade derusting standard on the steel surface. Then, carry out anti-corrosion coating according to design requirements, typically applying primer first, followed by intermediate and top coats. The thickness of each coat and the coating interval must comply with relevant standards.

3. Quality Control: At various stages of the processing, set up quality inspection points to conduct strict quality checks for each procedure. Inspection content includes dimensional accuracy, welding quality, and surface treatment quality. Perform overall dimensional verification of the completed pipe truss using measuring equipment such as total stations to check whether the truss's overall dimensions, member spacing, and diagonal lengths meet design requirements. Conduct non-destructive testing on welded parts, such as ultrasonic testing and radiographic testing, to ensure that welding quality meets design requirements.