1. What Precision Is Based On
Member fabrication accuracy follows the design drawings, shop drawings and acceptance standards such as the relevant acceptance requirements in GB 50205. Allowable deviations differ by member type (columns, beams, trusses, girts), so the standard stated on the drawings governs.
2. Controlling Deviation in Each Process
- Cutting: control surface squareness, kerf width and groove angle.
- Drilling: control hole position, diameter and the relative position of hole groups.
- Assembly and welding: control section geometry and longitudinal deviation.
- Straightening and shaping: correct welding distortion to restore required dimensions.
3. Managing Welding Distortion
Distortion is controlled by combining proper groove design, symmetrical welding sequence, pre-setting (counter-deformation) and post-weld straightening; important members follow the WPS and inspection plan with records.
4. How Parts Are Accepted
Dimensions are re-measured against the drawings with records for critical dimensions; dimensional inspection records and NDT reports are provided as required. Inspection methods and ratios are agreed per project, and special requirements can be discussed.
5. What to Prepare Before Fabrication
Provide complete drawings, tolerance requirements (especially hole positions and end preparation), inspection requirements and delivery information so manufacturability and scheduling can be reviewed against the drawings.
For custom member fabrication, see our custom steel components page, or send drawings directly for a review and quote.