PRODUCTION METHOD OF ROLLED SHEET FOR COLD-ROLLING, AND PRODUCTION METHOD OF PURE TITANIUM SHEET

• US 20180298479A1
• Filed: 03/16/2016
• Published: 10/18/2018
• Est. Priority Date: 03/25/2015
• Status: Active Grant

• Current Assignee: Klaus Schmidt
• Original Assignee: Klaus Schmidt
• Inventors: KIMIJIMA, Kazuya, KOBAYASHI, Masanori, SHIOGAMA, Tohru, TAMURA, Keitaro, FUJII, Yasuyuki
• Granted Patent: US 10,640,859 B2
• Time in Patent Office: Days
• CPC Class Codes: B21B 1/22 for rolling plates, strips, bands or sheets of indefinite length B21B1/42 takes precedence
• CPC Class Codes: B21B 2001/225 by hot-rolling
• CPC Class Codes: B21B 3/00 Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metalsaltering special metallurgical properties of alloys, other than structure consolidation or mechanical properties resulting therefrom C21D, C22F
• CPC Class Codes: C22C 14/00 Alloys based on titanium
• CPC Class Codes: C22F 1/18 High-melting or refractory metals or alloys based thereon
• CPC Class Codes: C22F 1/183 of titanium or alloys based thereon

Abstract

An aspect of the present invention is a production method of a rolled sheet for cold-rolling, the method being characterized by including: a hot-rolling step for forming a rolled sheet by hot-rolling a pure titanium material while coiling; and an annealing step for annealing the hot-rolled sheet after the hot-rolling step, the coiling temperature in the hot-rolling step being 500° C. or less, and the annealing step being controlled so that the percentage area of recrystallized grains in the microstructure of the hot-rolled sheet after annealing is at least 90% and the mean grain size of the recrystallized grains is 5 μm to 10 μm.

Claims

1. A method for producing rolled sheet for cold-rolling, the method comprising:

hot-rolling a pure titanium material while coiling; and

annealing a hot-rolled sheet formed by the hot-rolling,

wherein;

a coiling temperature in the hot-rolling is less than or equal to 500°

C; and

the annealing is controlled such that a percentage area of recrystallized grains in a microstructure of the hot-rolled sheet after the annealing is greater than or equal to 90%, and that a mean grain diameter of the recrystallized grains is greater than or equal to 5 μ

m and less than or equal to 10 μ

m.

2. The method according to claim 1, wherein:

the annealing comprises;

raising a temperature of the hot-rolled sheet formed by the hot-rolling to an elevated temperature T falling within a range of greater than or equal to 650°

C. and less than or equal to 750°

C., and

maintaining the hot-rolled sheet after the raising of the temperature, at the elevated temperature T; and

the maintaining is carried out for a duration t of selected from following ranges (1) to (3), depending on a range of the elevated temperature T;

(1) 160 sec≤

t≤

200 sec in a case of 650°

C.≤

T<

680°

C.;

(2) 80 sec≤

t≤

160 sec in a case of 680°

C.≤

T≤

720°

C.; and

(3) 40 sec≤

t≤

80 sec in a case of 720°

C.<

T≤

750°

C.

3. A method of producing a pure titanium sheet, the method comprising cold-rolling a rolled sheet obtained by the method of claim 1, without carrying out intermediate annealing.

4. The method of claim 3, wherein a total rolling reduction in the cold-rolling is greater than 85%.