METHOD FOR PRODUCING PRESS-FORMED PRODUCT

• US 20130199258A1
• Filed: 09/30/2011
• Published: 08/08/2013
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: Klaus Schmidt
• Original Assignee: Klaus Schmidt
• Inventors: Naitou, Junya, Okita, Keisuke, Ikeda, Shushi
• Granted Patent: US 9,358,602 B2
• Time in Patent Office: Days
• US Class Current: 72/342.5
• CPC Class Codes: B21D 22/022 by heating the blank or stamping associated with heat treatment C21D takes precedence
• CPC Class Codes: B21D 22/20 Deep-drawing special deep-drawing arrangements in, or in connection with, presses B21D24/00
• CPC Class Codes: B21D 22/208 by heating the blank or deep-drawing associated with heat treatment C21D takes precedence
• CPC Class Codes: B21D 22/22 with devices for holding the edge of the blanks B21D22/24 - B21D22/30 take precedence; shaping over a die without external former B21D11/02
• CPC Class Codes: B21D 24/02 Die-cushions
• CPC Class Codes: B21D 24/04 Blank holders; Mounting means therefor
• CPC Class Codes: B21D 37/16 Heating or cooling

Abstract

There is provided a useful method for producing a press-formed product without making the structure of a press tool complicated, which product has favorable formability in a level so as to be able to be produced by deep drawing, and which product is produced by press-forming a thin steel sheet with a punch and a die, in which the thin steel sheet is heated to a temperature not lower than an Ac₃ transformation point thereof, and the press-forming is then started, wherein the forming is carried out so that a temperature difference in the thin steel sheet is adjusted to be not higher than 200° C. at a stage when the thin steel sheet has reached one third of a forming height.

Claims

1. A method for producing a formed product by press-forming a thin steel sheet with a punch and a die, comprising:

heating the thin steel sheet to a temperature not lower than an Ac₃ transformation point thereof; and

then starting the press-forming,

wherein the forming is carried out so that a temperature difference in the thin steel sheet is adjusted to be not higher than 200°

C. at a stage when the thin steel sheet has reached one third of a forming height.

2. The production method according to claim 1, wherein the forming is carried out so that the time from the start of the forming to the finish of the forming is adjusted to be not longer than 0.3 seconds.

3. The production method according to claim 1, wherein the forming is started at a temperature higher than a martensitic transformation start temperature Ms of the thin steel sheet.

4. The production method according to claim 3, wherein the forming is started at a temperature not higher than 800°

C.

5. The production method according to claim 1, wherein the forming is started at a temperature not higher than a martensitic transformation start temperature Ms of the thin steel sheet.

6. The production method according to claim 1, wherein the forming is carried out by drawing with a blank holder.