1、SMAW Welding TechniquesWeld BeadA weld resulting from a passStringer BeadWeave BeadPasses Weld Pass - A single progression of welding along a joint. The result of a pass is a weld bead or layerRoot PassHot PassFill PassCover PassTechniques Stringer (drag) (whip) Weave Circles crescent zig zag box we
2、ave double JProgression (vertical) Up deeper penetration Higher deposit rate (lb/hr) Use near 90 degree travel angle or slightly up Down faster (point to point) less penetration for thin metal less dilution Use steep grag angleTravel Speed Stay on the leading edge of the puddleFlat Position Fillet/G
3、roove - stringer or weave, split bead or wide weaveHorizontal Fillet/Groove - stringers (small weave may be used in tight place) Bead Placement - bottom to topVerticalFillet/Groove - weave (or whip but not straight stringers)Root pass 6010 whipRoot pass 7018 straight stringer or weave (open closed)O
4、verheadSame as horizontal for Fillets6010 open root whip for flat face and keyhole control7018s stringersOH Butt Joints can be stringers or weavesDimensions Reinforcement -ASME flush 1/16 AWS flush 1/8 discuss keyholeing, metallic backing, nonmetallic backing, partial penetration, root openings, roo
5、t faces, tacking, tack grinding, fast freeze, and fill freeze Fill -as many as needed 1/8 per pass flat overload 3/16 vertical Cover -flush 1/16 high, 1/16 past edge600 included angleRoot facesTackingFeather TacksButt Joint Preperation1/16-1/8 (Joints without backing)Open Root Technique Use root ope
6、ning to allow increase in amperage for smoother welding Whip backwards for penetration Whip forwards to reduce penetration Do Not Weave a root pass. Maintain a short arc gap Stay slightly in front of the puddle at all times. Use the keyholing technique.Root faces - 0450 included angleRemove all mill
7、 scales and rustTacking - not in grooveTack away from coupon area.Flush on backingButt Joint Preperation(With Backing)Welding grooves with Backing Keep the root opening wide Make the root pass in one bead Avoid tight areas at the weld toesRestartsStagger all starts and stops or use run-on, run-off t
8、absFeather all restarts & start on top, or start in front and remeltDont restart in a coupon area.Also stagger all beads on a single pass.Use a longer arc length when starting a weld.Compare interpass grinding techniques vs. techniques for no interpass grinding.Craters Fill craters by reversing dire
9、ction at the weld end Use a short arc length to control heat. Electrode Work Angles450300700work angle (transverse angle) middle of joint directs heat between sides may need to direct more on heavy plateTransverse Angle EffectsDrag Angle increases PenetrationIncreases crown heightPush Angle gives sh
10、allow penetration, and flattens out the weld surface.Electrode Travel AnglesElectrode (arc) PlacementCurrent takes the path of least resistance. Therefore, the arc, and resulting weld, will go where the electrode end is closest to, NOT NECESSARILY IN THE DIRECTION THE ELECTRODE IS POINTINGArc Length
11、Longer arc lengths = increased puddle heat, flatter welds, deeper penetrationShorter arc lengths = less puddle heat, flatter welds, less penetrationUse arc length to control puddle size, penetration, and burn through.Normal arc length is 1/16” - 1/8”Use a slightly longer arc length during a start or
12、 restart.Helpful TipsClean your Welding Hood lensDrape the cable over your shoulder or kneeGet ComfortableWatch the puddle, not the arcConcentrate on steady travel speed and arc lengthSMAW Machine Setup DCEP (also called Direct Current Reverse Polarity) 77 - 150 Amp Range #5 fine amperage setting (a
13、pproximately 110 amps) Connect work lead Set for Constant Current (Variable Voltage)Amperage CalculationsRange: 77 - 150Fine tune dial: 0 - 10Desired amperage: 105 amps150 - 77 = 7373 / 10 = 7.37.3 x 6 = 43.843.8 + 77 = 120.8150 - 77 = 7373 / 10 = 7.3105 - 77 = 2828 / 7.3 = 3.836Range: 77 - 150fine tune dial: 0 - 10dial set at: 6Do SMAW Pipe Welding Techniques Lecture Now
