Thin, narrow tube and drawing apparatus and drawing method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-10271971-B2
Application number	US-201314417852-A
Country	US
Kind code	B2
Filing date	Aug 2, 2013
Priority date	Aug 3, 2012
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

Provided is a thin, narrow tube for use in a biodegradable medical device formed from a round tube made of a magnesium material as the base material, in which a desired outer diameter and an inner diameter are provided with good precision over the entire region in a longitudinal direction and a circumferential direction, and the length of biodegradation time can be controlled without changing a material composition. The thin, narrow tube is a thin, narrow tube of a biodegradable medical device, in which the thin, narrow tube is a round tube made of crystals containing magnesium (Mg) having a hexagonal crystal structure, and when the crystals forming the round tube are viewed in a round tube axis direction of the round tube, a hexagonal basal plane (0001) is oriented at a predetermined inclination angle with respect to a circumferential direction perpendicular to a radial direction (a direction from an inner surface to an outer surface) of the round tube.

First claim

The invention claimed is:

1. A tube of a biodegradable medical device,
said tube comprising a round tube made of a magnesium alloy (Mg) having a hexagonal crystal structure, and
the magnesium alloy forming the round tube, viewed in a round tube axis direction of the round tube, having hexagonal basal planes (0001) of crystals of magnesium alloy oriented at a predetermined inclination angle with respect to a circumferential direction perpendicular to a radial direction of the round tube,
wherein the orientation is specified in a pole figure obtained by using an electron back-scatter diffraction (EBSD) method performed on a radial cross-section of the round tube,
a signal caused by a high-density orientation structure A having a peak intensity of 6/7 or more of a maximum peak intensity in the hexagonal basal plane (0001) is present within an inclination angle of ±30° with respect to the circumferential direction,
the high-density orientation structure A is oriented, and
angle zones in which a signal caused by a low density orientation structure B having a peak intensity of 1/7 of the maximum peak intensity in the hexagonal basal plane (0001) is observed are discretely provided.

2. The tube according to claim 1 , wherein the high-density orientation structure A is further oriented in a spiral shape in a longitudinal direction of the round tube.

Assignees

• Aist

Inventors

• Hanada Kotaro
• Matsuzaki Kunio

Classifications

• B21C1/24

  by means of mandrels · CPC title

• A61F2210/0004

  bioabsorbable · CPC title

• C22C1/02

  by melting {(C22C1/1036 takes precedence)} · CPC title

• C21D2201/05

  Grain orientation · CPC title

• C22F1/06

  of magnesium or alloys based thereon · CPC title