Method for producing seamless metal pipe
AssigneeNippon Steel & Sumitomo Metal Corporation
InventorChihiro Hayashi
Life of this patent
Estimating the term…
Abstract
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°.
Claims5
A method for producing a seamless metal pipe, the method comprising:
- piercing-rolling a solid billet using a 4 roll inclined rolling mill that includes a pair of cone-shaped main rolls having roll shafts supported at opposing ends thereof and arranged horizontally or vertically to face each other across a pass line and a pair of cone-shaped auxiliary rolls having roll shafts supported at opposing ends thereof and arranged vertically or horizontally to face each other similarly across the pass line between the facing main rolls, wherein the diameter of the main rolls is larger than the diameter of the auxiliary rolls;
- and
- maintaining a feed angle β of the cone-shaped main rolls, a cross angle γ of the main rolls, a feed angle β′ of the auxiliary rolls, and a cross angle γ′ of the auxiliary rolls to be within following ranges:
- 5°≤β, β′≤25°;
- 3°≤γ, γ′≤35°;
- and
- 10°≤β+γ, β′+γ′≤55°.
Dependencies are inferred from the claim text.