Metallic structure control Materials which are generally used for construction of components to be lined are: carbon steel, alloyed steel or aluminium. Stainless steels, such as AISI 304, can be used only in special cases. Surfaces to be lined must be easily accessible, without sharp edges and corners. Prescriptions contained in the norm DIN 28051 must be carefully followed. Drawing of the item to be lined must be checked and approved by the lining applicator. All surfaces to be rubber lined must be processed, welded and finished as requested by DIN 28053. The surfaces to be lined must be free from oil, grease, paint. The surfaces to be lined must be continuous, welded, connected and grinded. In case of air spaces, drillings of the unlined sides is requested. If the drilling is not possible, it is necessary to perform a check of the welds which must be able to withstand mechanical or thermal stresses. The welds must be continuous, free from marginal cuts, porosity or absence of penetration or excessive protrusion.