Soldering, brazing & welding defects

soldering, brazing

1. YoucaN Brazing ,Soldering & Welding defects Compiled by Pravinkumar Kamatchi St.Josephs College of Engineering Assistant Professor

2. Braze Welding YoucaN

3. Brazing welding Filler metal melting point is above 427 C. Filler metal distribution in the joint by Capillary attraction . Metallic parts are J oined by a non-ferrous filler metal. The w/p to be joint is not melted here . The filler metal is only melted and due to the capillary attraction it adhered to the base metal. To obtain good strength surface cleaning is must one. YoucaN

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5. YoucaN Flux is a chemical compound applied to the joint surfaces before brazing. Its use is essential in the brazing process (with a few exceptions noted later.) The reason? Heating a metal surface accelerates the formation of oxides, the result of chemical combination between the hot metal and oxygen in the air.

6. Brazing Steel base metal + Brass filler rod is common Lower temp than welding: retains heat treatment (if present), minimizes grain growth. Strong but slow (careful preparation, cleanup) Furnace brazing is easily automated Kalpakjian en.wikipedia.org www.kirkframeworks.com YoucaN

7. Types of brazing Tourch ‘ Furnace Dip Induction YoucaN

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11. Brazing welding The added fluxes helps to remove the oxides present in the filler metal. Boric acid, chlorides, fluoxides are some of the fluxes. Copper based metals are used as a filler metal. For silver brazing silver is used as a filler metal. Applications: Pipe fittings Heat exchangers parts fabrications Manufacturing pressure vessels Jewellery applications YoucaN

12. Brazing welding Applications Low temperature process Dismantling of joints is possible Quick and clean Smooth surface finish can be obtained Disadvantages Skilled labours need Not suitable for mass production YoucaN

13. Soldering YoucaN

14. Soldering Filler metal melting point is less than 427 C. YoucaN

15. COMPONENTS OF SOLDERING YoucaN

16. Solder = Filler metal Soldering Applications: Printed Circuit Board (PCB) manufacture Pipe joining (copper pipe) Jewelry manufacture Easy to solder: copper, silver, gold Difficult to solder: aluminum, stainless steels (can pre-plate difficult to solder metals to aid process) Alloys of Tin (silver, bismuth, lead) Melt point typically below 430 degree C. Flux used to clean joint & prevent oxidation Zinc chloride, mixtures of zinc chloride and ammonium chloride. Typically non-load bearing YoucaN

17. Soldering Iron & Solder Wire Manual PCB Soldering Heating lead & placing solder Trim excess lead Heat for 2-3 sec. & place wire opposite iron YoucaN

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19. Welding Defects Cracks Cavities Solid inclusions Imperfect shape or unacceptable contour Incomplete fusion Miscellaneous defects YoucaN

20. Distortion from Welding Processes YoucaN

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28. (a) Desired profile for single V-groove weld joint, (b) undercut - portion of base metal melted away, (c) underfill - depression in weld below adjacent base metal surface, and (d) overlap - weld metal spills beyond joint onto part surface but no fusion occurs Weld Profile in Arc Welding YoucaN

29. Kalpakjian Welding Defects YoucaN

30. www.mig-welding.co.uk Welding Flaws: Incomplete Penetration (not enough heat input) YoucaN

31. YoucaN PRAVINKUMAR KAMATCHI