EXTRUSION FORMING OF NOZZLE

摘要

PURPOSE:To enhance swelling efficiency and to obtain a nozzle product only by cutting a roughly forged nozzle in a method that extrudes a roughly forged nozzle from slug by specifying the shape of material and swelling it without generating the change of shape. CONSTITUTION:A lump slug 11 having a projected part 13 on the body 12 with the nearly same curved face as external shape of the body 1 of the product is used. The projected part 13 is positioned at planned nozzle part. The diameter d4 is diameter d1 of the nozzle product plus finishing allowance. The projected shoulder part 14 is not rounded and the bottom 16 is made flat. The stug 11 is heated and put on a die 5 having the nearly same internal shape as external shape of the product. The projection 13 is fitted to a die hole 6, and the body 12 is extruded by lowering an extruding punch 7. Thus, a swelled part 17 having small rollover of the bottom face 16' is formed in the hole 6. The height h' of the rollover decreases with increase of the length h0 of straight wall. By making the length h0 longer than the length H of the nozzle product by finishing allowance, cutting of roughly forged nozzle can be performed omitting shape correction by secondary forging after extrusion.