Method of making aluminum brazing sheet

Patent metadata

Field	Value
Publication number	US-2025303504-A1
Application number	US-202218706909-A
Country	US
Kind code	A1
Filing date	Nov 1, 2022
Priority date	Nov 2, 2021
Publication date	Oct 2, 2025
Grant date	—

Abstract

Provided herein is a method for making aluminium brazing sheets comprises of, a) providing a core of first aluminium alloy; b) cladding said core, on one or two sides, with a second aluminium alloy, forming a laminate structure; c) performing a primary cold rolling of said laminate structure so as to roll bond core and cladding 5 alloy of said laminate structure; and d) performing at least one secondary cold rolling step of roll bonded laminate structure to obtain aluminium brazing sheet of desired thickness.

First claim

1 - 17 . (canceled)

18 . A process of making an aluminium alloy brazing sheet, the process comprising the steps of—
a. performing a primary cold rolling of a laminate structure comprising a core sheet of first aluminium alloy and a cladding sheet on at least one side of the core sheet with a second aluminium alloy, in a rolling mill to obtain a primary roll bonded laminate structure;
b. performing at least one secondary cold rolling of the primary roll bonded laminate structure in the rolling mill to obtain the aluminium alloy brazing sheet;
wherein the ratio (D/T) of the roll diameter (D) of the rolling mill in step a. to the thickness (T) of primary roll bonded laminate structure is in a range of 30 to 500, and the percentage of thickness reduction carried out during step a. is 40-70% further wherein the core sheet and the cladding sheet have their respective hardness (H core /H cladding ) in a ratio in the range of 0.8 to 1.2 and the primary roll bonded laminate structure exiting the rolling mill has a temperature in a range of more than 50 up to 150° C.

19 . The process as claimed in claim 18 , wherein the primary rolling is performed with rolling speed in a range of 2 to 600 meters per minute (mpm).

20 . The process as claimed in claim 18 , wherein the core sheet and the cladding sheet have their respective thickness in a ratio in the range of 5 to 20.

21 . The process as claimed in claim 18 , additionally comprising a step of annealing the core sheet and the cladding sheet before primary cold rolling in step a.

22 . The process as claimed in claim 21 , wherein the annealing step is carried out at a temperature of 180-450° C. for 1-6 hours.

23 . The process as claimed in claim 18 , additionally comprising a step of annealing the aluminium alloy brazing sheet after step b.

24 . The process as claimed in claim 23 , wherein the annealing step is carried out at a temperature of 180-450° C. for 1-6 hours.

25 . The process as claimed in claim 18 , wherein the core sheet and the cladding sheet are surface treated before the primary cold rolling.

26 . The process as claimed in claim 25 , wherein the surface treatment is selected from chemical cleaning and mechanical abrasion.

27 . The process as claimed in claim 26 , wherein the chemical cleaning is carried out with an inorganic acid selected from HCl, H2SO4, HNO3, or an alkali selected from NaOH or KOH.

28 . The process as claimed in claim 26 , wherein the mechanical abrasion is carried out with emery paper, steel brushes of confirmations selected from straight wire, twisted wire, and criss-cross wire.

29 . The process as claimed in claim 25 , wherein the core sheet and cladding sheet have surface roughness, Ra (Roughness Average) of above 0.5 microns.

30 . The process as claimed in claim 18 , wherein the primary roll bonded laminate structure has width in a range of 300-1500 mm.

31 . An aluminium alloy brazing sheet comprising:
a. a core sheet of first aluminium alloy; and b. a cladding sheet on at least one side of the core sheet with a second aluminium alloy;
wherein the sheet has Silicon particles greater than 400 particles/sqmm/% Si content.

32 . The brazing sheet as claimed in claim 31 , wherein variation in thickness of the cladded layer in the laminate is ±0.4%.

33 . The brazing sheet as claimed in claim 31 , wherein the incipient melting of the silicon particles starts at 570° C.

Assignees

• Hindalco Industries Ltd
• Indian Institute Of Tech Madras

Inventors

• Panigrahi Sushanta Kumar
• Srivastava Vivek

Classifications

• B32B15/016 Primary

  all layers being formed of aluminium or aluminium alloys · CPC title

• B23K35/286

  Al as the principal constituent · CPC title

• B21B2003/001

  Aluminium or its alloys · CPC title

• B21B3/00

  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 metals}(altering special metallurgical properties of alloys, other than structure consolidation or mechanical properties resulting therefrom C21D, C22F) · CPC title

• B23K2103/10

  Aluminium or alloys thereof · CPC title