Aluminum alloy precision plates

Patent metadata

Field	Value
Publication number	US-12371768-B2
Application number	US-202017765345-A
Country	US
Kind code	B2
Filing date	Sep 29, 2020
Priority date	Oct 4, 2019
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

The present invention relates to plates with a thickness of between 8 and 50 mm and made from aluminum alloy with a composition, as % by weight, Si: 0.7-1.3; Mg: 0.6-1.2; Mn: 0.65-1.0; Fe: 0.05-0.35; at least one element selected from Cr: 0.1-0.3 and Zr: 0.06-0.15; Ti<0.15; Cu<0.4; Zn<0.1; other elements <0.05 each and <0.15 in total, the remainder aluminum, and the method for manufacturing same. The plates according to the invention are particularly useful as precision plates, in particular for producing elements of machines, for example assembly or inspection equipment. The plates according to the invention have improved dimensional stability in particular during the machining steps, while having sufficient static mechanical properties, and excellent suitability for anodizing.

First claim

The invention claimed is:

1. A method for manufacturing an aluminum alloy plate with a final thickness of between 20 and 30 mm, wherein
a) a rolling ingot is cast from aluminum alloy with the composition, as % by weight, Si: 0.7-1.3; Mg: 0.6-1.2; Mn: 0.85-1.0; Fe: 0.05-0.35; at least one element selected from Cr: 0.1-0.3 and Zr: 0.06-0.15; Ti<0.15; Cu<0.04; Zn<0.1; other elements <0.05 each and <0.15 in total, remainder aluminum,
b) said rolling ingot is homogenized,
c) said rolling ingot is rolled at a temperature of at least 340° C. and no more than 420° C. to obtain a plate,
d) optionally heat treatment and/or cold rolling of the plate thus obtained is carried out,
e) a solution heat treatment of the plate, optionally heat treated and/or cold rolled is carried out, and said plate is quenched,
f) said plate thus solution heat treated and quenched is stress relieved by controlled stretching with a permanent elongation of 1 to 5%,
g) aging of the plate thus stretched is carried out,
h) optionally said plate thus aged is machined to obtain a plate with a final thickness of at least 20 mm;
wherein product of maximum deflection difference in directions L and LT multiplied by rolling-exit thickness is less than 4, differences in deflections considered for obtaining maximum value being firstly difference in deflection between deflection measured for a bar of dimensions 400 mm×30 mm×rolling-exit thickness and deflection measured for said bar after machining of ¼ of thickness thereof, and secondly difference in deflection between deflection measured for the previous bar and deflection measured for said previous bar after supplementary machining of ¼ of thickness thereof, all deflection measurements being made with the bar placed on two supports 390 mm apart and the deflections being expressed in mm, all measurements being made before optional final machining;
wherein the plate is a precision plate.

2. The method according to claim 1 , wherein the Cr content is between 0.15 and 0.25% by weight and the Zr content is less than 0.05% by weight.

3. The method according to claim 1 , wherein the Fe content is between 0.08 and 0.15% by weight.

4. The method according to claim 1 , wherein the homogenizing temperature is between 515° C. and 545° C.

5. The method according to claim 1 , wherein the hot-rolling temperature is maintained at at least 350° C. and the maximum rolling mill draft of passes during hot rolling is less than 50%.

6. The method according to claim 1 , wherein the hot-rolling temperature is maintained at at least 350° C. and the maximum rolling mill draft of passes during hot rolling is less than 50%.

7. The method according to claim 1 , wherein exit temperature of the hot rolling is no more than 410° C.

8. A plate with a final thickness of between 20 and 30 mm made from aluminum alloy with a composition, as % by weight, Si: 0.7-1.3; Mg: 0.6-1.2; Mn: 0.85-1.0; Fe: 0.05-0.35; at least one element selected from Cr: 0.1-0.3 and Zr: 0.06-0.15; Ti<0.15; Cu<0.04; Zn<0.1; other elements <0.05 each and <0.15 in total, remainder aluminum, obtained by:
a) a rolling ingot is cast from the aluminum alloy with the composition
b) said rolling ingot is homogenized,
c) said rolling ingot is rolled at a temperature of at least 340° C. and no more than 420° C. to obtain a plate,
d) optionally heat treatment and/or cold rolling of the plate thus obtained is carried out,
e) a solution heat treatment of the plate, optionally heat treated and/or cold rolled is carried out, and said plate is quenched,
f) said plate thus solution heat treated and quenched is stress relieved by controlled stretching with a permanent elongation of 1 to 5%,
g) aging of the plate thus stretched is carried out,
h) optionally said plate thus aged is machined to obtain the plate with the final thickness of at least 20 mm;
wherein product of maximum deflection difference in directions L and LT multiplied by rolling-exit thickness is less than 4, differences in deflections considered for obtaining maximum value being firstly difference in deflection between deflection measured for a bar of dimensions 400 mm×30 mm×rolling-exit thickness and deflection measured for said bar after machining of ¼ of thickness thereof, and secondly difference in deflection between deflection measured for the previous bar and deflection measured for said previous bar after supplementary machining of ¼ of thickness thereof, all deflection measurements being made with the bar placed on two supports 390 mm apart and the deflections being expressed in mm, all measurements being made before optional final machining;
wherein the plate is a precision plate.

9. The plate according to claim 8 , having a yield strength Rp0.2 (LT) of at least 240 MPa, and/or an ultimate tensile strength Rm (LT) of at least 280 MPa, and/or an elongation at rupture A % of at least 8%.

10. The plate according to claim 8 , wherein the ratio between Taylor factor in longitudinal direction measured at 1/12th of the thickness and ½ of thickness is between 0.90 and 1.10, measurements being made before optional final machining.

11. The plate according to claim 8 , wherein the Cr content is 0.15-0.25% by weight and/or the Zr content is 0.08-0.13% by weight.

12. The plate according to claim 8 , wherein the Fe content is 0.08-0.15% by weight.

13. The plate according to claim 8 , wherein the Mg content is 0.6-0.8% by weight.

14. The plate according to claim 8 , wherein the Si content is 0.8-1.0% by weight.

15. The plate according to claim 8 , wherein the final thickness is between 25 and 30 mm.

Assignees

• Constellium Issoire
• Constellium Valais Sa
• Constellium Valais Sa Ltd

Inventors

• Arsene Sylvie
• Ratchev Petar
• Calabretto Nicolas
• Jaquerod Christophe

Classifications

• C22C21/02 Primary

  with silicon as the next major constituent · CPC title

• C22F1/043 Primary

  of alloys with silicon as the next major constituent · CPC title

• C22F1/002 Primary

  by rapid cooling or quenching; cooling agents used therefor · CPC title

• C22C21/08

  with silicon · CPC title

• C22C21/00

  Alloys based on aluminium · CPC title