tailieunhanh - Weld Joints

Welding joints are formed by welding two or more workpieces, made of metals or plastics, according to a particular geometry. The most common types are butt and lap joints; there are various lesser used welding joints including flange and corner joints. Invite you to reference the following presentations. | Weld Joints a Butt joint b Corner joint c T joint d Lap joint e Edge joint FIGURE Examples of welded joints. Method Strength Design Variability Small Parts Large Parts Tolerances Relibility Ease of Maintenance Visual Inspection Cost Arc welding 1 2 3 1 3 1 2 2 2 Resistance welding 1 2 1 1 3 3 3 3 1 Brazing 1 1 1 1 3 1 3 2 3 Bolts and nuts 1 2 3 1 2 1 1 1 3 Riveting 1 2 3 1 1 1 3 1 2 Fasteners 2 3 3 1 2 2 2 1 3 Seaming crimping 2 2 1 3 3 1 3 1 1 Adhesive bonding 3 1 1 2 3 2 3 3 2 Note 1 very good 2 good 3 poor. TABLE Comparison of various joining methods. Manufacturing Processes for Engineering Materials 5th ed. Kalpakjian Schmid 2008 Pearson Education ISBN No. 0-13-227271-7 General Summary Joining Process Operation Advantage Skill Level Required Welding Position Current Type Distortion Cost of Equipment Shielded metal arc Manual Portable and flexible High All ac dc 1 to 2 Low Submerged arc Automatic High deposition Low to medium Flat and horizontal ac dc 1 to 2 Medium Gas metal arc Semiautomatic or automatic Works with most metals Low to high All dc 2 to 3 Medium to high Gas tungsten arc Manual or automatic Works with most metals Low to high All ac dc 2 to 3 Medium Flux-cored arc Semiautomatic or automatic High deposition Low to high All dc 1 to 3 Medium Oxyfuel Manual Portable and flexible High All - 2 to 4 Low Electron beam laser Semiautomatic or automatic Works with most metals Medium to high All - 3 to 5 High beam 1 highest 5 lowest TABLE General characteristics of joining processes. Manufacturing Processes for Engineering Materials 5th ed. Kalpakjian Schmid 2008 Pearson Education ISBN No. 0-13-227271-7 Oxyfuel Gas Welding 2100 C 1260 C 3800 F 2300 F Inner cone Outer 3040 to 3300 C envelope 5500 to 6000 F Outer envelope pointed Acetylene feather Bright luminous Blue inner cone envelope a Neutral flame b Oxidizing flame c Carburizing reducing flame Filler rod Molten weld metal Base metal Gas mixture Welding torch Flame Solidified weld metal d .