What is the percentage of time a welding machine can be used continuously?
60%
Why is SMA welding current referred to as constant current?
An arc is a very low impedance. In order to limit the power and stabilize the arc, it is important that the current be fairly constant. To accomplish this, a SMAW supply will increase voltage if current begins to decrease, and vice-versa.
Why must a welder try to maintain a constant arc length?
Maintaining a constant arc length is important, as too great a change in the arc length will adversely affect the weld. As the arc length is shortened, metal transferring across the gap may short out the electrode, causing it to stick to the plate. The weld that results is narrow and has a high buildup, Figure 4-10.
When a constant current machine is being used if the arc gap increases the resistance will?
Challenge Board (Gabrielle Williams)
| A | B |
|---|---|
| When using a constant current machine, if the arc gap increases, the resistance will _____. | Increase |
| If the resistance increases when using a CC acr welding machine, the voltage must _____. | Increase |
| Each bead is cleaned before the next bead is made to prevent ___ insclusions. | Slag |
Do you push or pull with a stick welder?
Push or pull: Here the rule is simple. “If it produces slag, you drag,” says Leisner. In other words, you drag the rod or wire when welding with a stick or flux-core wire welder. Otherwise, you push the wire with metal inert gas (MIG) welding.
What is the general rule in determining the correct size of a finished weld bead?
the general rule is that the arc length should be the same as the diameter of the electrode. When practicing welding, reuse weld coupons (metal you are welding on) until all surfaces have been welded on.
When using a welding helmet What is the minimum number lens shade you should have?
According to OSHA’s Fact Sheet, MIG welding (GMAW) or flux-cored welding (FCAW) using currents of 60 to 500 amps requires a minimum lens shade level of a DIN number 10.
What is the minimum thickness of metal normally welded using the SMAW process?
1.6 mm
What are the 5 SMAW operation set up?
SMAW Welding Procedure
- Step 1 – Pre-Welding Familiarization. Prior to welding, you should read the user-manual of your SMAW welding machine.
- Step 2 – Safety.
- Step 3 – Setup.
- Step 4 – Strike an Arc and Position Rod.
- Step 5 – Begin Welding the Bead.
- Step 6 – Remove Slag and Examine the Weld.
When the welding current is too low?
Setting the amps too low will result in a tall, narrow bead lacking in penetration. The weld will be difficult to start and the arc prone to straying towards one side of a joint in preference to the other.
Can you tack weld with a stick welder?
Sure you can tack with stick. Same setting as welding. A tack is a removable weld.
What is 7018 welding rod used for?
The 7018 welding rods are used for pipe welding and structural steel welding and repair welding. This low-hydrogen, usually DC, all-position electrode can also be used with AC, which not many welders may know. The 7018 provides a good bead appearance and smooth, strong welds. It also works on higher strength steels.
Why does my welding rod keep sticking?
If you’re welding with amperage set too low, your electrode will be especially sticky when striking an arc, the arc will keep going out while maintaining the correct arc length or the arc will stutter. A sign of too much current is when the electrode becomes hot enough to glow.
What is a 6013 welding rod good for?
The 6013 electrode is best used for light to medium penetration on a thin metal, or sheet metal. The 6011 electrode offers more penetration than the 6013 so you can weld a slightly thicker material.
What is the best welding rod for rusty metal?
The 6011 welding rod still seems to be the best welding rod suited for these types of metals. The 6011 welding rod is generally used for general repairs, fabrication, and pipe welding. In other words, the 6011 welding rod is best for dirty metals.
Does welding rod go bad?
Yes, welding rods can go bad depending on the model of rod that is used and the conditions they are kept in. Welding rods hold a shelf life around 2-3 years in ideal conditions. Moisture has a negative impact on the shelf life of many rods as well as poor temperature conditions.
How can you tell if a welding rod is bad?
If there is any rust on the rod, if the flux has formed a dry, powdery coating, or if the flux has softened, the rod is bad and should not be used for anything other than non-critical welding on mild steel. If welding electrodes absorb moisture on the flux, it can cause bubbles to develop in the weld.
Can you dry out welding rods?
Using longer drying times or higher temperatures can easily damage the electrodes. For drying, remove the electrodes from the container and spread them out in the furnace because each stick electrode must reach the drying temperature.
Can you run 7018 downhill?
7018 will run downhill pretty good if you get it set up right but it’s like 6013 or 7014; you don’t get much penetration. Most of the time if you’ve pulled out the 7018 it’s because you’re going for max strength and you’re only going to get that with an uphand weld.
What’s the difference between 7018 and 8018?
7018 is more ductile than 8018. Imagine a crack in the edge of a bucket. If you don’t preheat, the bucket may sit there pretty stable without much internal tension. Open up that crack, and weld it, the now hot metal you introduced to fill the gap while very hot is just the size it needs to be to fill the gap.
Why do pipeliners wear pancake hoods?
So why do welders use pancake hoods? A pancake hood provides protection to a welder’s eyes and face. It’s a headpiece rigged up with a balsa box. The balsa box is a compact-shaped box crafted to protect the eyes and surround of the welder, and its unique function is to secure and support the lens of the headgear.