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© 2009 Harris Products Group Brazing & Soldering.

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Presentation on theme: "© 2009 Harris Products Group Brazing & Soldering."— Presentation transcript:

1 © 2009 Harris Products Group Brazing & Soldering

2 © 2009 Harris Products Group Braze Safety Keep your head out of the fumes Use enough ventilation and exhaust at the flame or work piece to keep fumes and gases from your breathing zone and general area Wear correct eye, ear, and body protection

3 © 2009 Harris Products Group Brazing & Soldering Filler metal melts at temperature below the melting point of the base metal Filler metal flows through joint via principle of capillary attraction Requires two closely fitted surfaces Brazing takes place above 840°F/450 C Soldering occurs below 840°F/450 C

4 © 2009 Harris Products Group How does it work?

5 © 2009 Harris Products Group Cohesion, is the attraction of like molecules. Molecules on the liquids surface have stronger attraction. This is called surface tension. Cohesion and Surface Tension

6 © 2009 Harris Products Group Adhesion Forces between unlike molecules is called adhesion. In a brazed joint there are strong adhesive forces between molten filler metal and the base metal walls. We call this wetting.

7 Capillary Area (closely fitted surfaces) Filler Metal Capillary Action Base Metals Capillary action is a combination of surface tension and adhesion. It pulls the molten alloy through the joint, and allows you to braze in all positions. © 2009 Harris Products Group

8 Tight clearance in./0.038 mm Wide clearance - up to in/0.254 mm Capillary action works best when close clearance can be maintained. Avoid a press fit – no clearance will limit braze alloy flow.

9 Thermal Coefficient of Expansion Metals expand as temperature increases – watch for change in clearance. Maintain – at brazing temperature. © 2009 Harris Products Group

10 Thermal Coefficient of Expansion Different types of metals expand and contract at different rates. Maintain – at brazing temperature.

11 © 2009 Harris Products Group Recommended braze clearance is: in/0.050 mm to in/0.127 mm Parent Material Braze Alloy

12 © 2009 Harris Products Group Magnified Braze Joint

13 CLEAN PARTS © 2009 Harris Products Group

14 Clean Parts Remove oil, grease, drawing compounds Remove oxide w/Scotch Brite, wire brush, grinder, etc. If grit blasting avoid embedding silicon, alumina, sand, etc. in base metal - hinders wetting Chemical cleaning, acid, alkaline, chemical degreasing

15 FLUX © 2009 Harris Products Group

16 Brazing Flux Dissolves surface oxides and protects against oxide formation during heating Formulated to be active at braze alloy melting range Is not designed to be the base metal cleaner Is visually clear at about 1100º F – a good base metal temperature indicator

17 © 2009 Harris Products Group White flux- for most brazing applications Black flux- for extended heating or high temperature localized heat

18 © 2009 Harris Products Group 500 F 1000 F 1500 F 2000 F Water boils out Flux bubbles Flux begins to melt Flux clear and quiet FLUX BEHAVIOR DURING HEATING CYCLE 1190 F (643 C) - Dynaflow, Stay Silv 15 solidus 1225 F (663 C)– Safety Silv 45 solidus

19 © 2009 Harris Products Group Remove flux residue Hot water & wire brush Let filler metal solidify before quenching Overheated parts may require different flux removal method: Grinding Chemical (dilute acid dip) cleaning Braze Flux Removal

20 © 2009 Harris Products Group Heating

21 © 2009 Harris Products Group Only heat fitting = Poor heat transfer

22 © 2009 Harris Products Group Heat tube first

23 © 2009 Harris Products Group Heat fitting second – even heat

24 Apply alloy when both parts reach brazing temperature © 2009 Harris Products Group

25 Direct heat to fitting to draw alloy into fitting © 2009 Harris Products Group

26 Heat tube

27 © 2009 Harris Products Group


29 Heat fitting

30 © 2009 Harris Products Group Apply filler metal only when base metal is at brazing temperature Use flame to draw alloy into the joint

31 Melting Point vs. Melting Range Pure elements have a melting point. – 1981 F, (1083 C) – 449 F, (232 C) Alloys have a melting range. Solidus - Melting starts. Above this - part solid / part liquid. Liquidus - Melting complete. Above this completely liquid. Brazing usually starts at the liquidus temperature. – May be below liquidus. © 2009 Harris Products Group

32 Copper – Phosphorus Filler Metals

33 © 2009 Harris Products Group Copper – Phosphorus Filler Metals Copper/phosphorus & copper/phosphorus/silver compositions Harris 0 Stay-Silv ® 2, 5, 6, 15, Dynaflow ® Use to braze copper to copper Also copper to brass with Stay-Silv ® white flux Do Not use on steel – joints may be brittle AWS BCuP classification

34 © 2009 Harris Products Group Examples: Solidus, Liquidus, Melting Range

35 © 2009 Harris Products Group Silver Braze Filler Metals

36 © 2009 Harris Products Group Silver Braze Filler Metals Safety-Silv ® 30, 35, 38T, 40T, 45, 56 Always requires use of Stay-Silv brazing flux Primarily used on steel, stainless, nickel, copper alloys, and dissimilar applications Tin added to lower temperature, nickel added for improved corrosion resistance and strength on carbides AWS BAg Classification

37 © 2009 Harris Products Group Examples: Solidus, Liquidus, Melting Range

38 © 2009 Harris Products Group Soldering Soldering is similar to brazing but at lower temperatures, below 840 F / 450 C Solders are primarily tin based alloys with various additions of lead, silver, antimony, zinc, etc. Heat sources include soldering irons, air/fuel torches, propane, and propylene

39 © 2009 Harris Products Group Solders Tin based solders have less strength than copper based brazing alloys, so solder joints require longer over lap. Usually 5X the minimum base metal thickness is specified to develop adequate strength.

40 © 2009 Harris Products Group Soldering Flux Like brazing flux, solder flux is designed to protect the base metal from oxidation Flux is available in liquid and paste form Solder flux is formulated to be active during solder melting ranges Solder flux residue must be removed after soldering to prevent corrosion. Non-active rosin fluxes are available for electrical or electronic applications where post-solder cleaning is not practical

41 General Strength Guidelines Tensile Strength of a Brazed Joint –Joint strength depends on several factors: Clearance between parts Base metal composition Service temperature Joint quality (voids vs. good penetration) Joint design The bulk tensile strength of silver braze alloys is 40, ,000 psi. When brazing copper-based alloys, failure will often occur in the base metal. When brazing steel or other ferrous metals, joint strength over 70,000 psi can be achieved under the right conditions. Keep in mind that braze joints are primarily lap type joints and strength is a combination of tensile and shear. Joint strength is directly influenced by the above mentioned factors. The only way to accurately determine tensile or other strength values is to test the brazed assembly.

42 To achieve adequate joint strength, pieces to be brazed should overlap 3 times the minimum base metal thickness. To achieve adequate joint strength, pieces to be soldered should overlap 5 times the minimum base metal thickness. General Strength Guidelines © 2009 Harris Products Group

43 Solder Joint Strength Stay-Brite Solder Stay-Silv 15 Can be stronger than brazing in some applications.

44 © 2009 Harris Products Group The Most Common Braze Problem

45 © 2009 Harris Products Group Inadequate Braze Penetration Void in capillary

46 © 2009 Harris Products Group The Possible Result

47 -A Guide To Brazing & Soldering Brochure -Harris Alloy Selection Wheel Chart -Harris HVAC/R & Plumbing Catalog -Website: -Live Chat on main -Instant messaging product and/or application support - Monday thru Friday 8:00 AM – 5:00 PM EST -Access this feature at the top of the tool bar at our website Product Information & Literature © 2009 Harris Products Group


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