Abstract: Waste plastics including solid plastics, thin plastics, and foamy plastics are fed into a ring die of an extrusion molding machine. The waste plastics are either semi-melted or melted, and are then extruded onto an outer circumferential surface the ring die through die cavities. Thus, granular plastic moldings are extruded onto the outer circumferential surface of the ring die through the die cavities, and are then cut or scraped from the outer circumferential surface of the ring die. The pellets have a melt-solidified surface, and have a strength sufficient to reach a predetermine zone in a raceway of a furnace and a grain diameter sufficient to be fed at a velocity higher than a limiting velocity thereof during injection to the furnace.

Abstract: An electric-resistance-welded steel pipe with high strength consists essentially of 0.05 to 0.30 wt. % C, 0.6 to 2.0 wt. % Mn, 0.03 to 0.70 wt. % Si, and 0.01 to 0.05 wt. % Nb. The balance is Fe and inevitable impurities, the steel pipe having a martensitic phase ratio of 60 to 100% and having a tensile strength of 120 to 170 kgf/mm.sup.2.

Abstract: An electric-resistance-welded steel pipe with high strength. The pipe consists essentially of (a) 0.05 to 0.30 wt. % C, (b) 0.6 to 2.0 wt. % Mn, (c) 0.03 to 0.70 wt. % Si, (d) (i) 0.5 wt. % or less Mo by itself or (ii) 0.5 wt. % or less Mo with 1.2 wt. % or less Cr or (iii) 0.5 wt. % or less Mo with 0.1 wt. % or less V or (iv) 0.1 wt. % or less V and (e) the balance being Fe and inevitable impurities. The steel pipe has a martensitic phase in an amount of 60 to 100% and has a tensile strength of 120 to 170 kgf/mm.sup.2. The steel pipe is useful as an impact bar for the inside of an automobile door.