6 Pipes and tubes of metal; Lined and coated pipes and tubes of metal; Metal pipes with lining for protection against wear; Metal building materials in the nature of metal boards, plates, panels, plankings, slabs, pipes, inserts, castings, fittings and linings having a coating based on minerals, ceramics, artificial resins and plastics, including in combination with other materials, all for use in lining and reinforcing bunkers, silos, pipelines, conveyor chutes and channels, mixers and other storage, conveying and processing equipment and installations for pourable or conveyable materials in bulk; metal building materials, namely, wear-resistant and abrasion-resistant metal building materials, in particular metal building boards, moulded and formed parts in the nature of metal plates, screen plates, panels, plankings, slabs, inserts, castings, fittings and linings for conduits, chutes, channels, conveyors, containers, bunkers, silos, mixers and pipes, hollow parts in the nature of metal tubes, tanks, containers, hoppers, plankings, inserts, castings, fittings and linings, metal pipes, pipe parts in the nature of hard overlay welded pipe parts, hard cast pipe parts, metal pipe bends, metal pipe fittings, metal pipe linings, metal pipe couplings and joints; Metal building materials, namely, sheet metal linings, reinforcements, namely, metal reinforcement materials for building, steel plates and sheets, moulded parts, namely, mouldings of metal for cornices, pipe parts, namely, metal pipe fitting, metal pipe supports, metal pipe couplings and joints, metal pipe clips and metal spacing inserts and inserts for recesses for protection against wear, with the aforesaid made substantially in whole or in part of metal; metal building materials in the nature of unprocessed and semi-processed materials of metal for protection against wear; Linings of metal for building purposes used as reinforcements for bunkers, silos, mixers, pipelines, conveyor chutes and channels and other storage, conveying and processing equipment and installations for pourable or conveyable bulk goods, with the aforesaid made substantially in whole or in part of metal