What factors will affect the crane steel plate deformation?

The thin plate structures such as beams and columns of bridge cranes and beam cranes not only undergo bending deformation after welding, but there are also local convex or concave wave deformations on the cover and web. More importantly, the strength and rigidity of the components are reduced.

So, what factors will affect the deformation of the steel plate?

The influence of the pre-bending of the main beam.

• In the manufacturing process of the main girder of bridge cranes and beam cranes, if the web pre-bending is too large or too small, it means that excessive welding bending deformation is selected to achieve a regular camber, which will increase the welding internal stress of the beam and cause the main beam deformation of the beam web.
• When the main beam is horizontally tortuous, tensile stress will occur on one side of the cover plate, the corresponding web plate will also have uniform tensile stress, and the other side of the cover plate will also have compressive stress.
• The superposition of these compressive stresses will cause larger compressive stresses in some parts of the web, and then cause the deformation of the web of the double-girder bridge crane.

Angular deformation caused by fillet welds.

• The beams and columns of bridge cranes and beam cranes are all made of cover plates, webs, ribs and other sheet materials, and they are connected by fillet welds.
• The welding angle deformation caused by the fillet weld is also one of the factors that cause the plate deformation.
• Because the fillet welds between the cover plate and the web, and between the cover plate and the ribs are not uniformly heated along the thickness of the plate, the welds shrink horizontally to form plate deformation.
• When the welding foot size is kept, the angular deformation resistance of the plate is proportional to the cube of the plate thickness.

Influence of longitudinal welding stress.

• Welding stress occurs in the longitudinal welds of beams and columns of bridge cranes and beam cranes.
• The compressive stress between the cover plate and the web is relatively large. When the compressive stress is greater than the critical compressive stress of the steel plate, the cover plate and the middle of the web will be deformed.
• The critical stress is proportional to the square of the plate thickness. The larger the plate thickness, the smaller the possibility of deformation.

The inherent deformation of the material itself.

• Some crane manufacturers do not have steel plate straighteners, and the materials used are not leveled.
• The deformation of beams, column covers, and webs has exceeded the promised deformation of beams and columns.