1. Copper

2. Resistance Welding Lesson Objectives When you finish this lesson you will understand: Learning Activities 1.View Slides; 2.Read Notes, 3.Listen to lecture 4.Do on-line workbook Keywords

3. Copper & Iron Sulfates Rosenqvist, Extractive Metallurgy McGraw-Hill, 1974 Copper Ingot Electrolytic Refined

4. Induction Furnace Melting

5. AWS Welding Handbook

7. Not Recommended Fair Good Excellent The lower thermal & electrical conductivity materials are weldable AWS Welding Handbook

8. Welds can be made with sheets having 30% or less IACS No Welds with IACS over 60%

9. Weld Force Weld forces are usually set to 50-70% of that used for the same thickness uncoated plain carbon steel Spot Welding

10. Weld Current: Higher than for plain carbon steel Weld Time: Shorter than for plain carbon steel Spot Welding

11. Spot Weld Experience with 65% Cu – 35% Zn Brass Class 1Class 2 Class 11 Increased Resistance Min Penetration Poor Electrode Life Excessive penetration Electrode Sticking Increased Nugget Dia. Resistance Welder manufacturers Association Bulletin # 25

12. Spot Welding Tungsten or molybdenum tipped electrode are preferred to minimize tip sticking Higher Resistance = Heat Soaking Lower Thermal Conductivity = Less Heat Loss

13. Resistance Welder manufacturers Association Bulletin # 25 More Spot Weld Experience with 65% Cu – 35% Zn Brass Cracks Under Load When Nugget Too Close to Edge

14. Welding of Unequal Thickness Brass

15. Seam Welding Problems: Shunting of Weld Current High thermal conductivity Low Electrical Contact Resistance Result: Limited Alloys Seam Weldable Need Electrical Conductivity less than 30% IACS

16. Flash Welding

17. Savage, Flash Welding, Welding Journal March 1962 Flash Welding Copper Characteristics: Low melting temp Narrow Plastic Range Result Rapid Upset at low force Immediate & Full Flashing Required Rapid Upset Low Pressure at Start to get Platen Motion Immediately Premature Interruption of Flashing Results in Low Temp & CL Defects Excessive Flashing will Overheat & Improper Upset

18. Flash Welding Leaded Copper Alloys are limited to approximately 1% Lead

19. High Frequency Welding Tube Butt SeamTube Butt SeamTube Mash Seam HF Induction Coil Nearly all Copper Alloys can by HF Welded - Tubing is a Popular Application

20. Electro-Brazing

21. Welds can be made with sheets having 30% or less IACS No Welds with IACS over 60%

22. Electro-brazing W. Stanley, Resistance Welding McGraw-Hill, 1950