Titanium slab for hot rolling produced by electron-beam melting furnace, process for production thereof, and process for rolling titanium slab for hot rolling

Patent metadata

Field	Value
Publication number	US-9962760-B2
Application number	US-201013148392-A
Country	US
Kind code	B2
Filing date	Feb 8, 2010
Priority date	Feb 9, 2009
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A titanium slab is appropriate for hot rolling, is produced by electron beam melting furnace, has superior linearity so that it can be fed into a hot rolling machine without performing breaking down process or other subsequent correcting process after production, and has good structure having no cracks at the corner parts. A process for production thereof is also provided. The titanium slab is directly produced by a mold of an electron beam melting furnace, and has the deformation of not more than 5 mm for the thickness direction versus the longitudinal direction and deformation of not more than 2.5 mm for the width direction versus the longitudinal direction, both per a length of 1000 mm of the slab. The process for production of this titanium slab for hot rolling has a step of using an electron beam melting furnace in which its rectangular mold has mold walls of a long side and mold walls of a short side, and a step of pouring molten metal from one of the mold walls of a short side. Furthermore, a mold having chamfered parts at the corner parts can be used in the process.

First claim

The invention claimed is:

1. A process for production of a titanium slab for hot rolling, comprising:
using an electron beam melting furnace, in which a rectangular mold having a ratio (W/D) of the width (W) versus the thickness (D) of the rectangular mold is in the range from 2 to 10 is equipped, in a melting chamber maintained at a reduced pressure,
pouring molten metal from the top of shorter side wall of the mold, wherein intensity of electron beam irradiated to the surface of the poured molten titanium pool in the rectangular mold is controlled in the manner which decreases the intensity from one of the shorter side walls of the mold to the opposite shorter side wall of the mold where the molten metal is poured,
withdrawing out from the rectangular mold a titanium slab having a deformation of not more than 5 mm for the thickness direction versus the longitudinal direction, a deformation of not more than 2.5 mm for the width direction versus the longitudinal direction, both per a length of 1000 mm of the slab, and having a ratio (L/W) of the length (L) versus the width (W) is not less than 5, into an ingot chamber maintained at a reduced pressure,
cutting off an interface of the melting chamber and the ingot chamber,
filling the ingot chamber with argon gas to recover pressure inside the ingot chamber until a normal pressure,
cooling the slab down to room temperature in the ingot chamber, and then moving the slab to the atmosphere.

2. The process for production of the titanium slab for hot rolling according to claim 1 , wherein chamfered parts are formed at corners of the rectangular mold and the chamfered part is shaped similar to the equilibrium solid phase line which is the interface between the molten metal pool in the mold and the surrounding solidified phase.

3. The process for production of the titanium slab for hot rolling according to claim 1 , wherein a mold is used in which chamfered parts are formed at corners of the rectangular mold, the chamfered parts are part of circular arc, and the radius of curvature (rc) of the circular arc is in a range of 2 to 50 mm.

4. The process for production of the titanium slab for hot rolling according to claim 3 , wherein a mold is used in which the radius of curvature (rc) of the chamfered parts of the rectangular mold has a proportional relationship with a ratio (α) of the length of a short mold wall in the thickness direction of the titanium slab versus a length of the long mold wall in the width direction of the slab.

5. The process for production of the titanium slab for hot rolling according to claim 1 , wherein the produced titanium slab has a ratio (W/T) of the width (W) versus the thickness (T) being in the range from 2 to 10, and a ratio (L/W) of the length (L) versus the width (W) being not less than 5, and the length thereof being not less than 5000 mm.

Assignees

• Tanaka Hisamune
• Yamamoto Norio
• Shiraki Takeshi
• Oda Takashi
• Miyazaki Yoshimasa
• Fujii Yoshihiro
• Takahashi Kazuhiro
• Toho Titanium Co Ltd
• Nippon Steel & Sumitomo Metal Corp

Inventors

• Tanaka Hisamune
• Yamamoto Norio
• Shiraki Takeshi
• Oda Takashi
• Miyazaki Yoshimasa
• Fujii Yoshihiro
• Takahashi Kazuhiro

Classifications

• B21B1/42

  for step-by-step or planetary rolling (making tubes by pilgrim-step rolling B21B21/00) · CPC title

• B22D11/041 Primary

  for vertical casting (B22D11/043, B22D11/049 - B22D11/059 take precedence) · CPC title

• Y10T428/12389

  having variation in thickness · CPC title

• B22D21/005

  with high melting point, e.g. Be 1280 degrees C, Ti 1725 degrees C · CPC title

• B22D11/001 Primary

  of specific alloys · CPC title