Claims:We claim:
1. A method to improve strength of dissimilar steel-aluminium cold metal transfer (CMT) weld-brazed joints comprising the steps of:
• taking aluminium alloy (AA5052) plate;
• taking dual phase steel (DP600) plate;
• cleaning the surfaces of the sheets using acetone prior to the joining in order to remove dirt;
• placing the aluminium alloy (AA5052) plate at the top and dual phase steel (DP600) plate at the bottom in lap configuration;
• using Aluminium based Silicon enriched (AlSi5) filler wire for cold metal transfer (CMT) weld-brazing;
• welding by cold metal transfer (CMT) weld-brazing to join the aluminium alloy (AA5052) plate at the top and dual phase steel (DP600) plate at predetermined constant weld feed rate, with predetermined overlapping distance, with predetermined boost phase current, and at predetermined weld feed rate (WFR) during wait phase;
• using pure argon (99.99 %) as shielding gas to protect the molten pool from atmospheric contamination.

2. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing with defect-free and efficient joining of dissimilar materials aluminium and steel in lap configuration is configured without increasing the filler deposition rate.

3. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing is configured to increment 6% to 13% of the joint efficiency.

4. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing joining is performed at constant weld feed rate (WFR) of 4 m/min.

5. The method as claimed in claim 1 wherein the aluminium alloy (AA5052) plate is of 1.5 mm thickness.

6. The method as claimed in claim 1 wherein the dual phase steel (DP600) plate is of 1.2 mm thickness.

7. The method as claimed in claim 1 wherein the Aluminium based Silicon enriched (AlSi5) filler wire used for the cold metal transfer (CMT) weld-brazing is of 1.2 mm diameter.

8. The method as claimed in claim 1 wherein the joining was performed using ER4043 (AlSi5) filler of 1.2 mm diameter with an overlapping distance of 25 mm.

9. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing is carried out at boost phase current 170 A.

10. The method as claimed in claim 1 wherein the weld feed rate (WFR) during wait phase is 10 m/min.

11. The method as claimed in claim 1 wherein by improving the wetting ability of weld-brazed joints at the same deposition rate, improved the load carrying capacity of the joints.

12. A conjoined plate of aluminum alloy (AA5052) and dual phase steel (DP600) plate as produced by dissimilar steel-aluminium cold metal transfer (CMT) weld-brazed joints.

13. The conjoined plate as claimed in claim 12, wherein the load to failure strength is configured of 6 - 6.2 kN or 6.6 - 6.78 kN for 25mm wide tensile test samples.

Dated 18th day of March 2020

Gopinath Arenur Shankararaj
IN/PA 1852
OF K&S PARTNERS
AGENT FOR THE APPLICANT
, Description:We claim:
1. A method to improve strength of dissimilar steel-aluminium cold metal transfer (CMT) weld-brazed joints comprising the steps of:
• taking aluminium alloy (AA5052) plate;
• taking dual phase steel (DP600) plate;
• cleaning the surfaces of the sheets using acetone prior to the joining in order to remove dirt;
• placing the aluminium alloy (AA5052) plate at the top and dual phase steel (DP600) plate at the bottom in lap configuration;
• using Aluminium based Silicon enriched (AlSi5) filler wire for cold metal transfer (CMT) weld-brazing;
• welding by cold metal transfer (CMT) weld-brazing to join the aluminium alloy (AA5052) plate at the top and dual phase steel (DP600) plate at predetermined constant weld feed rate, with predetermined overlapping distance, with predetermined boost phase current, and at predetermined weld feed rate (WFR) during wait phase;
• using pure argon (99.99 %) as shielding gas to protect the molten pool from atmospheric contamination.

2. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing with defect-free and efficient joining of dissimilar materials aluminium and steel in lap configuration is configured without increasing the filler deposition rate.

3. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing is configured to increment 6% to 13% of the joint efficiency.

4. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing joining is performed at constant weld feed rate (WFR) of 4 m/min.

5. The method as claimed in claim 1 wherein the aluminium alloy (AA5052) plate is of 1.5 mm thickness.

6. The method as claimed in claim 1 wherein the dual phase steel (DP600) plate is of 1.2 mm thickness.

7. The method as claimed in claim 1 wherein the Aluminium based Silicon enriched (AlSi5) filler wire used for the cold metal transfer (CMT) weld-brazing is of 1.2 mm diameter.

8. The method as claimed in claim 1 wherein the joining was performed using ER4043 (AlSi5) filler of 1.2 mm diameter with an overlapping distance of 25 mm.

9. The method as claimed in claim 1 wherein the cold metal transfer (CMT) weld-brazing is carried out at boost phase current 170 A.

10. The method as claimed in claim 1 wherein the weld feed rate (WFR) during wait phase is 10 m/min.

11. The method as claimed in claim 1 wherein by improving the wetting ability of weld-brazed joints at the same deposition rate, improved the load carrying capacity of the joints.

12. A conjoined plate of aluminum alloy (AA5052) and dual phase steel (DP600) plate as produced by dissimilar steel-aluminium cold metal transfer (CMT) weld-brazed joints.

13. The conjoined plate as claimed in claim 12, wherein the load to failure strength is configured of 6 - 6.2 kN or 6.6 - 6.78 kN for 25mm wide tensile test samples.

Dated 18th day of March 2020

Gopinath Arenur Shankararaj
IN/PA 1852
OF K&S PARTNERS
AGENT FOR THE APPLICANT