Though stick welding is the most commonly used form of arc welding, it is not easy for a beginner to create a quality weld. Stick welding requires more skill and expertise of specific techniques as opposed to wire welding when we need to just “point and fire”.

Tips

1.1 Choose Steel of Normal Range

Choose steels which come within the “normal range,” which includes the AISI-SAE 1015 to 1025 steels having silicon to a maximum of 0.1% and the sulfur content below .035%. Choosing the mentioned steels will help to make the process of stick welding uncomplicated as they weld at high speeds and has less tendency to crack.

While carbon steel and other low alloy steels having a chemistry composing over the “normal range”, there is a tendency for cracking especially while welding on rigid structures and heavy plates. To avoid this special precautions are to be followed. Also, it would not be advisable to use steels having high phosphorous and sulfur contents for production welding. However, in case they have to be welded, make use of the low hydrogen, small diameter electrodes. Slow travel speed welding will help to keep the puddle molten which allows the gas bubbles to have enough time to boil out thus resulting in a weld that is better finished.

2.2 Select a Joint Position and an Electrode which is Conducive to the Steel

The position of the Joint will have a marked impact on the quality of the finished weld. While welding on a gauge sheet steel of 10 to 18, we can obtain the fastest travel speeds when the work is positioned at an angle between 45 to 75 degrees. Keep in mind to avoid making a weld which is greater than what is required for the joint strength and not to over-weld as this can lead to burn through.

To weld mild steel plates which are equal or thicker than 3/16”, it is recommended to position the work flatly as it will help to make the operator manipulations of electrodes much easier. Finally, remember that high carbon and steels plates with low alloy are welded best when the work is position flatly.

3.3 Follow the Simple Principles for Fitup and Joint Geometry

1.For fast welding speeds and fine weld quality always choose joint dimensions. The right joint geometry is based on the foundation of certain simple principles: 1) The fitup should be consistent for the whole joint. As the steel sheet metal and nearly all lap and fillet joints are tautly secured for their whole length, the bevels ort gaps should be accurately controlled all over the whole joint. The slightest variation in a particular joint will put pressure on the welder to adapt for the variation for the fitup.

2 .For a decent bead shape and proper penetration there must be sufficient bevel – if not, it will prevent the electrode from entering the joint. To site an instance, a narrow and deep bead may have shortage in penetration thus creating strong chances for cracking.

3. Adquate root hole is required for complete penetration. Too much root opening will waste the weld metal besides slowing down the welding speed. Always remember that the opening of the root must be stable with the electrode’s diameter that is being used.

4. For a fast and quality weld a backup strip or a root face is required. Foe feather edge preparations, a slow and costly seal bead in necessary. But for double V butt joints not having a land are feasible where the cost of the seal bead is offset by simpler edge preparation and limiting the root opening to 3/32”.

Seal beads can generally be welded on work positioned flatly with 3/16” E6010 at about 150 amps DC+. Utilize 1/8” at about 90 amps DC+ for overhead, vertical or horizontal butt welds. Weld using EXX18 electrode at about 170 amps for seal beads and low hydrogen.

1.4 Avoid Over welding and Build

Make sure that fillets have uniform legs and an almost horizontal bead surface. The buildup must rarely go over 1/16”. Any over buildup is expensive both in time and material, increases distortion and does little to the strength of the weld. For instance, to double the area of a fillet, it needs four times the amount as the weld metal. Again, it will cost two-third more for welding a butt weld a&Pi” plate – with a single-V having 1/8” land a 1/32” root opening – when the over buildup nears 1/8”.

1.5 Always Clean a Joint Prior to Welding

It is crucial to get rid of excessive rust, scale, grease, oil, paint and moisture from the exterior of the joint so that any porosity can be avoided and to get the perfect weld travel speeds. In case these elements can’t be removed make use of electrodes having E6011 (35 or 180) or E6010 (5P+) so as to perforate through the pollutants and penetrate inside the base steel. The travel speed can be slowed to give time for the gas bubbles to simmer away from the liquid weld before it can freeze out.

1.6 Select the Electrode Size Correctly

Electrodes that are large can weld at great power for higher deposit rates. So it is recommended that the largest electrodes practical be used so as to be constant with fine weld quality. However, the size of the electrode can be restricted on root passes and sheet metal, where a burn-through can develop. As a thumb rule, 3/16” is considered as the maximum size of the electrode that is practical for overhead or horizontal welding and for low hydrogen welding, what is considered as practical is a maximum size of 5/32”. Moreover, sometimes joint dimensions limit the diameter of the electrode that fits well to the joint.

Weld Defects – Trouble Shooting

Given below are some common problems while stick welding and ways to set them right.

Spatter

Even though spatter has no effect on the strength of a weld, it gives the weld a poor look and increases the cost of cleaning it. There are many ways by which excessive splatter can be checked. The first is trying to decrease the power, making sure that polarity is right and that it remains within the ambit for the particular size and type of electrode that is being welded with. Spatter can also be controlled by trying to make the arc length shorter. When the molten metal is moving ahead of the arc, try changing the angle of the electrode. Lastly, check for arc blow conditions (usually called a “wandering arc”) and make certain that the electrode isn’t wet.

Wet Electrodes

If the arc action is erratic and rough in spite of the polarity and the power are as specified by the recommendations of the electrode manufacturer, then there are chances that the electrodes are wet. Try using dry electrodes from another fresh container. In case the problem persists, store electrodes in open containers in a cabinet that is heated.

Undercutting

Usually, undercutting is just a problem about appearance though it can affect the weld strength in cases where the weld is subjected to fatigue or loaded in tension. To get rid of undercut, decrease the power and slow the travel speed or just decrease size till it is a puddle size that you can control. Then you can change the angle of the electrode so that the metal in the corners are held by the arc force. Avoid any excessive weaving and use a steady travel speed.

Wandering Arc

While DC welding, stray magnetic fields makes the arc wander from the course that it is aimed at. This creates more problems in complicated joints and at high currents. To keep a wandering arc in check, the best way is to switch over to AC welding and even if this does not work, try reducing the arc length or using smaller electrodes or lower currents. You can also alter the electrical path by changing the connection of the work to the opposite end of the piece or by making the connections in many places. This can be done by making the weld towards the finished welds or the heavy tracks using run-out tabs, adding steel chunks to shift current path or pinning little plates across the seam at the end of the weld.

Porosity

Most porosity is invisible though the more severe ones can weaken a weld. So it is important that you know what causes porosity to develop and how to fight it. The first step is to get rid of the rust, scale, moisture, paint and other dirt particles from the joint. Make sure to retain the molten puddle for longer periods so as to let the gas bubbles simmer out before they can freeze. In case the steel has lower manganese or carbon content, or a high phosphorous or sulfur (free machining steel) content, then it must be welded by using a low-hydrogen electrode. There are times when the sulfur content of free machining steels is as high as to prevent a successful weld. Reduce admixture of the base metal into weld metal by making use of fast travel speeds and a low current for low penetration. Making use of a shorter length arc can also be tried. For low hydrogen electrodes, a light drag method would be ideal. For holes seen on the surface, the same solutions used in the case of porosity can be followed. When using the E6010 or 11 electrodes, ensure that they are not dried out.

Poor Fusion

Proper fusion is when the weld is physically and strongly bond to both the walls of the joint to form a solid bead across the joint. The often visible lack of weld must be removed in order to have a sound weld. To overcome a poor fusion, try a stringer bead technique and a greater current. Ensure that the rims of the joint and not contaminated or use an electrode of E6010 or 11 to get out the dirt. In case the hole is excessive, use a weave technique so as to fill the hole or give better fitup.

Shallow Penetration

By penetration, we mean the depth entered into by the weld inside the base metal which is usually invisible. Penetration to the lowest point of the joint is necessary for all full-strength welds. To combat shallow penetration try using slower travel or higher currents. Make use of small electrodes so that it reaches into the deep and narrow grooves. Always remember to have a small space at the bottom end of the joint.

Cracking

Since there are various kinds of cracks which occur in different places in the entire weld, cracking can be a very complex subject. All cracks are likely to be serious as it can cause complete disaster of a weld. Most of the cracking is due to high alloy or carbon content or a high content of sulfur at the bottom of the metal. To control such cracking check out these tips:

  1. Try welding with the low hydrogen electrodes
  2. For the rigid joints and heavier plate, use higher preheats
  3. Decrease penetration by utilizing small electrodes and low currents as this will reduce the alloy content that is deposited to the weld from the melted bottom metal.
  4. Before the arc is broken, fill each and every crater.
  5. On numerous fillet or pass welds, ensure that the first bead has enough size and are either convex or flat shaped so as to restrict cracking till the later beads can be added on for support. For increasing the bead size, try using lower travel speed and a shorter arc technique or weld 5° uphill. Always continue to weld as long as the plate is hot.
  6. Since chances for cracking is more prone to rigid parts, whenever possible, try welding towards the end that is unrestrained. Leave a 1/32” space between plates to allow shrinkage movement when the weld cools. To relieve stresses, peen each weld while still hot.

Conclusion

By closely following the tips give above, even an amateur welder can create a weld of high quality. While facing problems during welding, if you are able to troubleshoot and make the necessary corrections, can help even a starting stick welder turn into a professional in absolutely no time!