TUBE END BENDING PREVENTING DEVICE IN SIZING MILL FOR SEAMLESS STEEL TUBE

摘要

PROBLEM TO BE SOLVED: To reduce the cutting allowance of a tube end and to product a seamless steel tube with an excellent yield by providing a wear resistant layer on the guide surface coming into contact with the steel tube and moreover arranging so that the gap between a rolling roll and the guide becomes a specified value or below. ;SOLUTION: A sizing mill is composed of plural roll stands, and the guide 4 for preventing the bending of the seamless steel tube under rolling is provided between the final stand 1 and the stand 2 just before the final stand. In this guide 4, the gap between the roll and the guide is meant by (g) and the difference of the roll caliber surface and the guide inner peripheral surface is meant by (d). In order to roll without the tube being caught (g) is necessitated to be ≤3mm. Further, the guide is arranged so that (d) becomes e.g. ≤1.5mm at the maximum. Also, wear resistant metal containing Cr₃C₂ powder (compounding ratio 50%) is thermally sprayed on the guide surface coming into contact with the tube.;COPYRIGHT: (C)1998,JPO