5　Production Process

5.1　The Horizontal Extrusion Process

5.1.1　The horizontal extrusion process shall comprise raw-material preparation，extrusion forming，pipe finishing，heat treatment and product inspection.

5.1.2　Raw-material preparation shall include straightening，peeling，cutting，drilling，end-face machining，visual inspection and grinding.Other procedures may be added depending on product variety.

5.1.3　Extrusion forming shall comprise billet cleaning，reheating，descaling，lubrication for expanding，piercing or expanding，descaling，secondary reheating，lubrication for extrusion，extruding，cooling and collection.Other procedures may be added depending on product variety.

5.1.4　Pipe finishing shall comprise straightening，cutting to length，pipe-end treatment，inside and outside surface processing，weighing，spray marking，printing and packing.Other procedures may be added depending on product variety.

5.1.5　Online solution treatment，offline solution treatment，normalizing & tempering treatment，annealing and the like may be used for heat treatment.

5.1.6　Product inspection shall include non destructive test（NDT），inside and outside surface inspection and outline dimension inspection.Other procedures may be added depending on product variety.