Pipe welding downhill has the advantage of speed, and as a result, it tends to be less fatiguing and easier than welding uphill. However, welding downhill isn't suitable for all applications because it does affect the formation of the weld.
While both methods have their advantages and disadvantages, uphill is generally preferred for its higher quality and better penetration, especially in thicker materials. However, downhill is faster and can be used for thinner materials.
On thinner-wall pipe, downhill welding enables operators to run “hot and fast,” increasing productivity compared to welding uphill, which is required on thicker wall pipe to increase heat input to ensure complete penetration.
Downhill progression welding can also cause weld defects especially on thicker materials, such as lack of fusion. Lack of fusion may occur in downhill progression when the weld puddle gets in front of the arc. Burn through is a defect that occurs when the weld metal burns through the base material.
This process is great for structural steel and most hobby projects. You can weld in all positions— flat, horizontal, vertical, uphill, and downhill— and you can vary the process to achieve good penetration for thick steel or surface penetration for thin steel.
Vertical welds can be done in either vertical up (moving bottom to top in the weld joint) or vertical down (moving top to bottom in the weld joint). Vertical up is typically more common, especially on thicker materials.
By welding uphill you'll be able to penetrate deeper into the metal, stacking the weld up and giving it time to penetrate into the joint. For thin metal, such as on automotive welds, you can weld downhill and even do a stringer. The big difference comes with the metal thickness.
Pipe welding downhill has the advantage of speed, and as a result, it tends to be less fatiguing and easier than welding uphill. However, welding downhill isn't suitable for all applications because it does affect the formation of the weld.
A light dragging motion with a short arc is used when downhill welding with an E-7018 electrode. 5. A 10° to 30° travel angle is recommended for downhill welding.
Welding in the overhead position—with the workpiece directly above the welder—is widely thought to be the most difficult welding position. Pipe welding is also well known to be particularly challenging welding work.
A weld that is too small or too short for the application can fail from tension, compression, bending or torsional loads. If a weld is made to be in an application where a cyclical load is going to be applied, it will be beneficial to consider a filler metal option with increased impact toughness and ductility.
The problem you have while welding upside-down is that gravity wants to assist the weld pool in forming nice, red hot globs which have a nasty habit of falling off and landing on you. Lower power settings and higher wire-speed will help but the main thing is practice.
6010/6011 is traditionally used for downhill. 6013 or 6014 can also be used. All these have a thin highly fluid slag which makes slag inclusions much less likely. 6013 is designed to be a low-penetrating rod which is why you should probably use it on unusually thin stuff like under 12 ga.
Flat Welding Position
Also known as the downhand position, the flat position is the easiest of all the welding positions. A flat position is the common type of weld. It is the first weld that beginners learn. In this position, you are not welding against gravity.
Downhill welding uses a drag travel angle of 10°–25°. A downhill root pass of a groove weld can be welded with a stringer bead or a weave bead.
You Should Pull When Stick Welding
Put in simpler terms, you should be pulling the rod towards you when using any welding process that produces slag. This includes submerged arc welding, electroslag welding, flux-cored arc welding and shielded metal arc welding (SMAW), more commonly known as stick welding.
Vertical stick welding a tee joint requires you to weld from the bottom up: A good technique is to guide the welding rod in a weaving motion in the shape of a triangle. See illustration A for that. However, if you pause for a brief moment after every few triangles you will get better penetration and fusion.
In most cases, the gun should be angled slightly in the direction of motion. This is called the travel angle, and 15 degrees is a good place to start. Looking at the gun from the end of a seam, the angle of the gun to the work is called the work angle. For a butt joint, 90 degrees is ideal.
It is found that the welding quality is higher when the range of welding angle is 38–46°, the welding quality is lower when the range of welding angle is 54–68°. If taking in account both of welding quality and porthole die strength requirement, the preferred welding angle is recommended to be in the range of 46–54°.
TIG welding is often considered the strongest weld since it produces extreme heat, and the slow cooling rate results in high tensile strength and ductility. MIG is also an excellent candidate for the strongest type of weld because it can create a strong joint.
Downslope allows the welding current to be reduced gradually, allowing the metal to cool more slowly than it would without downslope control.
Thus the weakest area of the weld is the throat. One other approach is that the other parts of the weld are subjected to normal stress and shear stress. But in the throat in addition to both bending is also there which makes it weakest.
The sign of a quality and secure weld is that you will not see the weld at all. If there is any visible evidence of a weld, it will be in the form of a bead that has no holes or cracks and is uniform overall. A high-quality weld is made using high-quality materials.
The strength of the weld is determined by the filler metal used and its effective area. The effective area of a weld is determined by multiplying the length of the weld times the throat. So the bigger the throat the larger the effective area and thus the stronger the weld.