Welding Techniques and Defects

Welding Techniques and Defects

SMAW Welding Techniques Weld Bead A weld resulting from a pass Weave Bead

Stringer Bead Passes Weld Pass - A single progression of welding along a joint. The result of a pass is a weld bead or layer

Fill Pass Cover Pass Root Pass Hot Pass

Techniques Stringer (drag) (whip) Weave Circles crescent zig zag box weave

double J Progression (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 angle Travel Speed Stay on the leading edge of the puddle

Flat Position Fillet/Groove - stringer or weave, split bead or wide weave Horizontal Fillet/Groove - stringers (small weave may be used in tight place) Bead Placement - bottom to top Vertical

Fillet/Groove - weave (or whip but not straight stringers) Root pass 6010 whip Root pass 7018 straight stringer or weave (open closed) Overhead

Same as horizontal for Fillets 6010 open root whip for flat face and keyhole control 7018s stringers OH Butt Joints can be stringers or weaves

Dimensions Reinforcement -ASME flush 1/16 AWS flush 1/8 discuss keyholeing, metallic backing, nonmetallic backing, partial penetration, root openings, root 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 edge Butt Joint Preperation (Joints without backing) 600 included angle Root faces Tacking

Feather Tacks 1/16-1/8 Open Root Technique Use root opening 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. Butt Joint Preperation (With Backing)

Root faces - 0 450 included angle Remove all mill scales and rust Tacking - not in groove Tack away from coupon area. Flush on backing Welding grooves with Backing

Keep the root opening wide Make the root pass in one bead Avoid tight areas at the weld toes Restarts Stagger all starts and stops or use run-on, run-off tabs Feather all restarts & start on top, or start in front and remelt

Dont 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 direction at the weld end Use a short arc length to control heat. Electrode Work Angles 700 300 450

work angle (transverse angle) middle of joint directs heat between sides may need to direct more on heavy plate Transverse Angle Effects

Electrode Travel Angles Drag Angle increases Penetration Increases crown height Push Angle gives shallow penetration, and flattens out the weld surface.

Electrode (arc) Placement Current 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 POINTING

Arc Length Longer arc lengths = increased puddle heat, flatter welds, deeper penetration Shorter arc lengths = less puddle heat, flatter welds, less penetration Use 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 restart. Helpful Tips Clean your Welding Hood lens Drape the cable over your shoulder or knee Get Comfortable Watch the puddle, not the arc Concentrate on steady travel speed and arc length

SMAW Machine Setup

DCEP (also called Direct Current Reverse Polarity) 77 - 150 Amp Range #5 fine amperage setting (approximately 110 amps) Connect work lead Set for Constant Current (Variable Voltage) Amperage Calculations Range: 77 - 150

Range: 77 - 150 Fine tune dial: 0 - 10 fine tune dial: 0 - 10 Desired amperage: 105 amps

dial set at: 6 150 - 77 = 73 150 - 77 = 73 73 / 10 = 7.3

73 / 10 = 7.3 105 - 77 = 28 7.3 x 6 = 43.8 28 / 7.3 = 3.836

43.8 + 77 = 120.8 Do SMAW Pipe Welding Techniques Lecture Now

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