For instance, a thin floor structure with deformation between the beams is a clear sign of damage. A damaged structure increases structural loads on the liners, requiring higher toughness and thicker lining material to compensate. In such cases, a recommended solution is Hardox^® 450 with a thickness of 18 or 20 mm. 
A new or well-maintained structure provides an ideal foundation for designing a lightweight liner package. This allows for the use of thinner materials like Hardox^® 500 Tuf in the tail section.
 
The Hardox^® liner must be fully welded around its edges, but it should first be securely tack welded before final welding to the structure. To prevent deflection in the middle area, plug welding the liner is essential. The dimensions of the plug weld are determined by the plate thickness and the welding method used. While smaller plug welds are generally favored to minimize wear, they must still be sufficiently sized to ensure a high-quality weld. To minimize wear, position the longer side of the plug weld perpendicular to the direction of material flow.
The figure below illustrates tack welding, welding direction and plug welding. For high-quality tack welding, special attention should be given to the weld stops. More guidance is available in Chapter 14 of the SSAB Welding Handbook.

a) Tack welding b) Fillet weld passes c) Plug welding with welding start.

The distance between liner plates should be tight. As a rule of thumb, the gap can be equal to the plate thickness.