There were two main problems with the "hardened" steels. In practice is was difficult to get the surface hardening any deeper than 4mm, where the full working depth needed to be 10mm. Therefore, the rolls frequently needed to be removed and re-hardened. The second problem was that the hardened shell was vulnerable to cracking, and thus spoiled the finish of the rolled product.

Changing the roll design to a welded type using Weldclad 4 enabled the full working depth of the roll to be used, with consistent hardness throughout. Once the roll had worn down to it's minimum size it could be rebuilt again with Weldclad 4 at a significant cost saving over replacement of the original iron rolls. Additionally the Weldclad 4 rolls dramatically reduced "pick up" problems and were less prone to marking during adverse mill conditions.