METHOD FOR PRODUCING SEAMLESS METAL PIPE

摘要

A solid billet is piercing-rolled using a 4 roll-type inclined rolling mill including larger-diameter cone-type main rolls arranged horizontally or vertically to face each other across a pass line and smaller-diameter auxiliary rolls arranged vertically or horizontally to face each other similarly across the pass line between the facing main rolls, while maintaining a feed angle β and cross angle γ of the main rolls and a feed angle β′ and cross angle γ′ of the auxiliary rolls to be within the ranges: 5°≦“β, β′”≦25°; 3°≦“γ, γ′”≦35°; and 10°≦“β+γ, β′+γ′”≦55°.

主权项

1. A method for producing a seamless metal pipe, the method including piercing-rolling a solid billet, the method comprising:
using a 4 roll-type inclined rolling mill that includes a pair of larger-diameter cone-type main rolls supported at both ends and arranged horizontally or vertically to face each other across a pass line and a pair of smaller-diameter auxiliary rolls supported at both ends and arranged vertically or horizontally to face each other similarly across the pass line between the facing main rolls; and maintaining a feed angle β of the cone-type main rolls, a cross angle γ of the main rolls, a feed angle β′ of the auxiliary rolls of a cone type, and a cross angle γ′ of the auxiliary rolls to be within following ranges.
5°≦“β, β′”≦25°3°≦“γ, γ′”≦35°10°≦“β+γ, β′+γ′”≦55°