Title:
A METHOD FOR MANUFACTURING AN ULTRA-HIGH-TENSILE, EXPANDED METAL OF STEEL
Document Type and Number:
WIPO Patent Application WO/2003/020456
Kind Code:
A1
Abstract:
The invention relates to a method for manufacturing an ultra-hig-tensile expanded metal of steel. The initial work piece used and constituted of a metal work piece of iron, which has been alloyed with chromium, nickel and carbon in predetermined proportions, is plastically cold worked in order to, during controlled temperature conditions with respect to the metal, that is to say the work piece and fina product, provide a strong deformation hardening at the same time as the alloy maintains a good ductility.
Inventors:
CARLSSON LEIF (SE)
GROTH HANS (SE)
Application Number:
PCT/SE2002/001577
Publication Date:
March 13, 2003
Filing Date:
September 04, 2002
Assignee:
AVESTAPOLARIT AB (SE)
CARLSSON LEIF (SE)
GROTH HANS (SE)
International Classes:
B21D31/04; C21D7/10; C21D6/04; (IPC1-7): B21D31/04; C21D7/10
Foreign References:
| US2018085A | 1935-10-22 | | | |
| US4649607A | 1987-03-17 | | | |
Attorney, Agent or Firm:
Bjelkstam, Peter (Bergenstråhle & Lindvall AB Box 17704 S- Stockholm, SE)
Claims:
Claims
| 1. |
!. A method for manufacturing an ultrahightensile expanded metal of steel, characterized in that the initial work piece used and constituted of a metal work piece of iron alloyed with chromium, nickel and carbon in predetermined proportions, is plastically cold worked to provide a strong deformation hardening that gives the final product a strong, many times increased strength, that is to say a high yield point, as compared to the yield point of the initial work piece. |
| 2. |
A method according to claim 1, characterized in that the work piece consisting of iron that is plastically worked is alloyed with 17% Cr, 7% Ni and 0, 1% C or closely related alloys. |
| 3. |
A method according to claim 1, characterized in that the alloyed work piece is formed in traditional machines for manufacturing expanded metals to increase its yield point from an original low yield point to a final product that completely or partially obtains a higher yield point. |
| 4. |
A method according to claim 1,2 or 3, characterized in that the original low yield point is about 300 MPa and the higher one is more than 700 MPa. |
| 5. |
A method according to claim 1,2 or 3, characterized in that the initial work piece is cooled to or is kept at a controlled temperature before and during the forming operation to obtain a controlled, maximal strength independently of the degree of deformation during the forming operation. |
| 6. |
A method according to any one of the preceding claims 1,2, 3 or 5, characterized in that the temperature to which the work piece has been cooled or the temperature that is maintained during the forming operation is about196 < T < 70°C. |
| 7. |
A method according to claim 1,2, 3,5 or 6, characterized in that the final product is cooled or is kept at a controlled temperature to obtain a controlled maximal strength in dependently of the degree of deformation during the forming operation. |
| 8. |
A method according to claim 7, characterized in that the temperature to which the final product is cooled or the temperature that is maintained after the forming operation is about196 zu T < 70°C. |
Description:
A method for manufacturing an ultra-high-tensile, expanded metal of steel The present invention relates to a method for manufacturing an ultra-high-tensile expanded metal of steel.<BR> <P>4 When manufacturing an expanded metal one usually starts from metallic work pieces, preferably of soft steel with good forming properties. During the forming operation one achieves a certain degree of deformation hardening, which however is insufficient for obtaining an ultra-high-tensile final product. In case one should start from a material that initially is ultra-high- tensile with a yield point preferably more than 700 MPa, this material would not have sufficient ductility to be formed to expanded metal. This is so because the material would break during the forming operation.
The object of the present invention is to provide a method for manufacturing an ultra-high-tensile expanded metal, which is constituted of iron that has been alloyed to give a strong deformation hardening when being subjected to plastic cold machining in combination with maintaining good ductility of the alloy at the same time as the final product achieves a yield point more than 700 MPa. The characterising features of the invention are stated in the subsequent claims.
Thanks to the invention one has now provided a method for manufacturing an ultra-high-tensile expanded metal of steel, which in an excellent manner fulfils its object at the same time as the manufacture can take place very rationally with already existing machines to low cost.
The invention is described in more detail with the aid of the embodiment below.
In a preferred embodiment of the invention, the expanded metal manufactured according to the invention is constituted of a work piece of iron, which has been alloyed with chromium, nickel and carbon in predetermined proportions. In the example chosen the iron is alloyed with 17% Cr, 7% Ni and 0, 1% C or alloys closely related to these and that the temperature of the work piece before and/or during the manufacturing operation has achieved or is kept at a controlled level, wherein a strong but controlled deformation hardening is achieved when plastic cold working the work piece in combination with maintaining a good ductility of the alloy. Furthermore, the temperature of the finally formed expanded metal is controlled after the working operation. The alloyed metal work piece that forms the initial work piece is formed in traditional machines for expanded metal fabrication to increase its yield point from an original, low yield point of about 300 MPa to a final product that completely or partially obtains a yield point of more than 700 MPa.
