6 Pipes and tubes of metal; lined and coated pipes and tubes of metal; pipes and tubes of metal with linings or coatings for protecting against wear, corrosion, abrasion, decay, acid, moisture and heat, and for promoting slip; wear-resistant, corrosion-resistant, abrasion-resistant, adhesion-resistant, impact-resistant, rot-resistant, acid-resistant, moisture-resistant, heat-resistant and slide-promoting 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 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; wear-resistant, corrosion-resistant, abrasion-resistant, adhesion-resistant, impact-resistant, acid-resistant and moisture-resistant metal building materials in the nature of building panels of metal, mouldings of metal for cornices, plankings, coverings or inserts, hollow bodies in the nature of metal tubes, tanks, containers, hoppers, plankings, inserts, castings, fittings and linings, 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 made of metal, in particular cast stainless steel, cast steel or grey cast iron, including in connection with other materials and aggregates in the form of hard 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 bulk goods; Wear-resistant, impact-resistant, abrasion-resistant and impact and abrasion-resistant panels in the nature of wall, floor and building panels of metal, preformed metal parts in the nature of tubes, plankings, coverings, inserts, castings and fittings and linings in the nature of sheet metal linings and linings of metal for building purposes made from highly wear-resistant cast stainless steel, cast steel, grey cast iron, all with and without subsequent tempering, for use in the transport of bulk goods, in particular on silos, slides and chutes for heavy industry, the metallurgical industry and in the mining industry, and for use in transporting stones and soil