When fastening a bolt, it is essential to apply the prescribed torque to achieve the correct pre-tension – typically about 80% of the bolt’s yield strength. Bolts perform best when they are long and slender, since this design allows for more deflection without losing pre-tension. In contrast, conical bolts sunk into the plate create a shorter clamp length. Another important consideration is the condition of the wear plates and backing plates. Hardox^® plates are extremely hard, and any deflection caused by thermal cutting can result in a mismatch, creating unwanted gaps between the liner and backing plate. These gaps can be difficult to tighten properly and can compromise the pre-tension, increasing the risk of the nut loosening over time. To avoid this, it is important to use flat liner plates and ensure that the backing plate is straight and properly aligned. 

Hardox® steel is delivered with flatness guarantees, and one of its key properties is minimal distortion during thermal cutting. This low distortion ensures that plates can be pre-tightened properly without the risk of gaps forming between the liner and backing plate. As a result, bolted joints remain secure throughout the entire operation.  When installing liners, remove any dirt, deburr the edges of both the liner and backing plates, and cross-tighten the bolted joints. 

If the liners can only be installed from the liner side, achieving the correct pre-tension becomes more challenging due to uncertainties in friction caused by countersinking. For better results, machined countersinking and lubrication are recommended to improve installation quality. In contrast, countersinking done via plasma or waterjet creates rougher surfaces, which increases friction uncertainty and makes it harder to achieve consistent pre-tension.