Difference between revisions of "Stick Welding User Guide"

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Revision as of 12:23, 2 February 2021

Shop Area: Metal Shop

Tool: Stick Welder

Requires in-person training: Yes 

Procedure Number

UG 130-02, Rev. 1

Date

2/2/2021

 

GENERAL

Millermatic 211 Stick Welder.png

  • The electrode is composed of solid metal rod which is coated with metal powders and other compounds which are held into the surface by a binding agent.
  • Stick welding is primarily used for heavy-duty iron and steel welds but it can also be used to weld other metals such as aluminum.

SAFETY

  • Always wear approved face shield while operating the welder.
  • Wear a welder helmet that fits your head, face and neck comfortably. It should cover the top of your head down to where your head and neck meet. Those with a mask that lifts are helpful because they let you take a peek at your work, but you may want an auto-darkening helmet too that comes with shields designed for different jobs.
  • Wear approved welder’s gloves and jacket.
  • Wear dry, hole-free insulating gloves and body protection.
  • Before operating equipment, remove tie, rings, watches and other jewelry, and roll sleeves up past the elbows. Remove all loose clothing and confine long hair.
  • Non-slip footwear or anti-skid floor strips are recommended.
  • Closed toe shoes are required when working in a shop area.
  • Turn off all equipment when not in use.
  • Do not use worn, damaged, undersized, or poorly spliced cables.
  • Do not drape cables over your body.
  • Clamp work cable with good metal-to-metal contact to workpiece or worktable as near the weld as practical.
  • Insulate work clamp when not connected to workpiece to prevent contact with any metal object.
  • Do not connect more than one electrode or work cable to any single weld output terminal.
  • Do not touch hot parts bare handed.
  • Allow cooling period before working on gun or torch.
  • To handle hot parts, use proper tools and/or wear heavy, insulated welding gloves and clothing to prevent burns.
  • Keep your head out of the fumes. Do not breathe the fumes. Welding produces fumes and gases. Breathing these fumes and gases can be hazardous to your health.
  • Do not weld on coated metals, such as galvanized, lead, or cadmium plated steel, unless the coating is removed from the weld area, the area is well ventilated, and while wearing an air-supplied respirator. The coatings and any metals containing these elements can give off toxic fumes if welded.
  • Arc rays from the welding process produce intense visible and invisible (ultraviolet and infrared) rays that can burn eyes and skin. Sparks fly off from the weld.
  • Wear an approved welding helmet fitted with a proper shade of filter lenses to protect your face and eyes when welding or watching.
  • Wear approved safety glasses with side shields under your helmet.
  • Use protective screens or barriers to protect others from flash, glare and sparks; warn others not to watch the arc.
  • Wear protective clothing made from durable, flame-resistant material (leather, heavy cotton, or wool) and foot protection.

REFERENCE

PROCEDURE

Basic elements of stick welding:

Stick welding is also known as shielded metal arc welding (SMAW).

1.  Prepare Surface

  • Use a wire brush or grinder to remove dirt, grime or rust from the area to be welded. Unclean surfaces can lead to cracking, porosity, lack of fusion or inclusions. Clean surfaces will provide a solid electrical connection to maintain arc quality.

2.  Current setting:

  • Use an AC electrode. Make sure you have it set correctly for your application.
  • Amperage setting will depend on the diameter and type of electrode.
  • Select amperage based on the electrode, typically 1 amp for each .001-inch of electrode diameter.
  • Adjust welder by 5 to 10 amps at a time, until the ideal setting is reached.

3.  Length of arc:

  • The optimal arc length, or distance between electrode and puddle, is the same as the diameter of the electrode (the actual metal part within the flux covering).
  • The correct arc length varies with each electrode and application. As a good starting point, arc length should not exceed the diameter of the metal portion (core) of the electrode. For example, an 1/8-inch 6010 electrode is held about 1/8 inch off the base material.
  • Holding the electrode too close to the joint decreases welding voltage, which creates an erratic arc that may extinguish itself or cause the electrode to freeze faster and produces a weld bead with a high crown.
  • An arc length that is too short will create greater potential for the electrode sticking to the base material.
  • Excessively long arcs (too much voltage) produce spatter, low deposition rates, undercuts and often leaves porosity.
  • Too long of an arc length will create excess spatter in the weld joint. There is also a high potential for undercut.

4.  Angle of travel:

  • Stick welding in the flat, horizontal and overhead positions uses a drag or backhand welding technique.
  • Hold the electrode perpendicular to the joint, and then tilt the top in the direction of travel approximately 5 to 15 degrees.
  • For welding vertical up, use a push or forehand technique and tilt the top of the electrode 0 to 15 degrees away from the direction of travel.

5.  Manipulation of electrode:

  • To create a wider bead, manipulate the electrode from side to side, creating a continuous series of partially overlapping circles in a ‘Z,’ semi-circle or stutter-step pattern.
  • Limit side-to-side motion to two times the diameter of the electrode core.
  • To cover a wider area, make multiple passes or use stringer beads.
  • Note that on material 1/4 inch and thinner, weaving the electrode is typically not needed because the bead will be wider than necessary. A straight bead should be adequate. 
  • When welding vertical up, focus on welding the sides of the joint. Move across the middle of the joint slowly enough so that the weld puddle can catch up, and pause slightly at the sides to ensure solid tie-in to the sidewall.

6.  Speed of travel:

  • Travel speed should allow you to keep the arc in the leading one-third of the weld pool.
  • To establish the optimal travel speed, first establish a weld puddle of the desired diameter, and then move at a speed that keeps you in the leading one-third of the puddle.
  • If you travel too slowly, the heat will be directed into the puddle and not into the weld, leading to cold lap or poor fusion. 
  • Excessively fast travel speeds will also decrease penetration, create a narrower and/or highly crowned bead, and possibly underfill or undercut (the area outside of the weld is concave or recessed).

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TROUBLESHOOTING

Clean and Dry up the Joint before Welding - Remove any rust, paint, moisture or oil from the surface of the joint so as that you can attain the intended travel speed. This will also help you to deal with other issues such as porosity which tends to weaken the weld. Alternatively, you can use certain brands of high-speed electrodes to penetrate through the substances, deep into the metal.

Don’t Reuse an Electrode - If you want a clean weld that is free from porosity try as much as possible not to use a partially used electrode for your subsequent weld. As such you should always prioritize quality and not factor the extra cost as much.

Have the Necessary Finishing Supplies - Consider having all the necessary supplies for a good looking and neat stick weld. They include sandpaper, angle grinder, and a chipping hammer which will come in handy in doing some final touches and also help in the clean-up process when you are done welding.

Wet electrodes - A rough arc action could be as a result of wet electrodes. If this is the case, you should substitute the electrodes with dry ones.

Improper Fusion - A proper fusion is when the weld is attached strongly to the walls of the joint resulting into a solid bond across the joint. Improper fusion is physically visible and it has to be dealt with in order for you to have a sound weld.  To correct improper fusion, make a weld pass with a higher current and make sure that the joint is clean.  If this does not solve the problem, try an alternative solution like the weave technique to fill up the gap.

Wandering arc - An arc can wander from the intended direction. Try low currents and if this does not work try to reduce the arc length or use smaller electrodes.

Shallow Penetration - This is simply the depth of the welder and it is not normally visible. Penetration to the bottom of the base metal is necessary for sturdy welds. Slower travel or higher currents can help to counter shallow penetration. You can also use a small electrode to dig deep into narrow grooves.

Cracking - Cracking is common phenomena and it can occur at any point throughout the weld. Most cracks are as a result of high content of sulfur, carbon or alloy in the base metal and it can potentially lead to failure of the entire project. Low hydrogen electrodes are known to significantly reduce the risk of cracking. You can also try and reduce penetration if there is a risk of cracking.

Other Tips:

  • If your amperage is too low, your electrode will be especially sticky when striking an arc, your arc will keep going out while maintaining the correct arc length or the arc will stutter.
  • Once you get an arc going, if the puddle is excessively fluid and hard to control, your electrode chars when it’s only half gone, or the arc sounds louder than normal, your amperage might be set too high. Too much heat can also negatively affect the electrode’s flux properties.
  • When the amperage is set too high, the puddle will be excessively fluid and hard to control. This can lead to excess spatter and higher potential for undercut. In addition, the electrode will become hot — perhaps hot enough to glow toward the end of the weld—which can adversely affect the shielding properties of the flux.
  • Traveling too slowly produces a wide, convex bead with shallow penetration and the possibility of cold-lapping, where the weld appears to be simply sitting on the surface of the material. This can result in insufficient penetration in those areas. Traveling too slowly can also focus the heat into the puddle and not into the base material. 
  • Traveling too fast will create a thinner/undersized bead that will have more of a V-shaped ripple effect in the puddle rather than a nice U-shaped, or stacked dimes, effect.
                                                  END OF THE PROCEDURE