| 摘要 |
PROBLEM TO BE SOLVED: To improve the sliding characteristic of a barrel for a plastic extruder and to prolong the service life of a screw as a mating material. SOLUTION: The barrel for a plastic extruder is composed of a high silicon stainless steel having a composition containing, by weight, <=0.1% C, 2-6% Si, <=3% Mn, 4-9% Ni, 8-18% Cr, <=2% Mo, 0.2-4% Cu and 0.1-2% of (Nb+Al). The barrel is manufactured, e.g. by the steps of: (a) working the high silicon stainless steel after solution heat treatment into a prescribed rough shape by machining; (b) applying precipitation hardening treatment to increase hardness; (c) applying grinding to the surface to modify deformation due to heat treatment; (d) applying gas nitriding treatment in an NH3 atmosphere to precipitate nitrides in the surface layer part; and (e) finishing the inside peripheral surface into the prescribed dimensions by grinding to get the barrel finished.
|
