Strenx® hot-rolled high-strength structural steel

In practice, for trailer applications, distortion due to welding is more critical than the static strength of the welds. Follow these tips to minimize the amount of distortion due to the welding operation: 

  • Weld with as low a heat input as possible
  • Minimize the cross sectional area of the weld, as in the illustration below
  • Prebend, clamp or angle the parts before welding in order to compensate for the shrinking
  • Avoid irregular gaps in the root
  • Use symmetrical welds, as in the illustration below
  • Minimize reinforcements and optimize the throat thickness of the fillet welds
  • Weld from rigid areas to loose ends
  • Optimize the welding sequence

Cross-section of the weld and how it influences the angle deviation.

Use a symmetrical welding sequence.

To avoid a curved or deformed longitudinal beam after welding of the web, displace the web in relation to the center of the flange. This makes it possible to locate the longitudinal welds in the neutral layer of the flanges, as in the illustration below.

Displacing the web in relation to the flange makes it possible to weld in the neutral layer of the flange, which avoids deformations from welding.

Strenx® cold-rolled high-strength structural steel (CR)

In order to avoid heavy deformation of Strenx® CR steels, follow these guidelines:

  • Weld with as a low heat input as possible.
  • Use a wire with a small diameter (0.8 mm).
  • Downhill welding technique reduces the heat input and is recommended if permitted by the application and the production conditions.
  • If the application allows a small gap between the welds, intermittent welding can be used.
  • If the application requires a sealed connection, silicon or adhesives could be used instead of welding to seal the connection and prevent corrosion to arise.
  • Use lap welds instead of butt welds.
  • Welding of thin sheets requires a short distance between the tack welds (80–120 mm).
  • Power sources for MAG welding have greatly evolved, making it possible to weld thin sheets with approximately 50% lower heat input.
  • If the joint is accessible from both sides, resistance spot welding can be used instead of fusion welding.
  • Avoid welding and use mechanical joining, which ensures very low or no deformation.