As a beginner in the field of welding, you might ask “ Are welds strong enough?” or “How strong is stick welding?”
Welding is considered to be a bulletproof process. It is the most efficient way to join two pieces of metal together. And if you explore, you might see welders using welding techniques all different from each other.
And right here, you might get confused and start to question. “Which technique or method is the best?” or you might think “What type of welding is stronger?”
The answer to your question is that it all depends on the nature of the metal you are using and the tensile strength you want to achieve.
Now to satisfy your curiosity, we will be discussing in detail one of the few most famous welding techniques. So if you are looking for someone to answer your confusion, this might help you erase them.
We have many welding methods which can produce the same strength we want. But there can be different variations based on multiple factors.
Whether it’s the environment of welding, metal preparation, or electrode type, these all play a significant role in deciding how strong the weld will be.
Most importantly, the person who is welding has also a great impact on the strength of welding. Even if the machinery and settings are the same, a veteran welder can make stronger welds as compared to a newcomer.
What is stick welding?
Before discussing “How strong is stick welding?”, first we need to know what exactly stick welding is. Stick welding is also known by many other names. Manual arc welding or shielded metal arc welding (SMAW) are a few alternative names for stick welding. It is a versatile, simple, and effective welding technique.
It is a type of welding in which the filler material is melted using electricity. The electrode and metal joints melt all at once and the two metal pieces are fused. The joint is filled with filler material at the same time.
How strong is stick welding?
Now coming to our actual concern, many factors are involved to ensure the strength of the weld. Stick welding is considered one the most recommended method when it comes to the strength of the weld.
Here we will be talking about several factors that affect weld strength:
- Tensile strength
- Metal preparation
- Stacked beads
- Ductile strength and brittleness
- Welding environment
- Welders skills
If you look closely at the electrodes, you will see four numbers written on them. These numbers are mentioned on the rods for easy recognition. The tensile strength of the rod which is measured in pounds per square inch is represented by the first two numbers.
However, it doesn’t matter what the tensile strength is when the weld is not done properly. If done carelessly, the metal strength can dramatically drop.
If the weld is not strong enough, incomplete fusion might be one of the reasons for its weakness. While welding you have to ensure that the filler material should tie into both metal pieces. If not, the weld is weak.
There are some cases when a welder only focuses on one side of the metal and keeps ignoring the other side. This results in incomplete fusion and the weld is weak.
Another way to check how strong is the welding is the porosity in the weld. If you find holes in the weld, then it is weak for sure.
However, a tight arc can be used to avoid this hassle. You should practice holding a tight arc in your welding processes to guarantee maximum weld strength. This means that the tip of the electrode should not be more than that of steel. The rod should only be touching the steel when you are welding.
Now if you see here, there is a difference in the strength of these two rods. The tensile strength of 6010’s is 10,000 pounds less than that of 7018 rods. This is because these rods are differently designed.
The specialty of 6010 and 6011 rods is to penetrate through the metal at its maximum. These electrodes are known for their one characteristic known as “digging”. They can weld through oil, dust, paint, and rust as well.
Despite these characteristics, they still don’t match the strength of 7018 rods.
Similarly, there is another factor that you can have under consideration if you want to check how strong the stick welding is.
Metal preparation is very essential if you want to enhance the weld’s strength. For this, the metal surface should be all cleaned. Any kind of paint, oil, or dirt should be removed from the surfaces. This will result in complete fusion and stronger will be the weld.
You can do stick welding without removing the mill scale. Mill scale is a thin coating left from the steel factories. However, this little coating can prevent you reach the strong weld. It will not let reach the maximum strength.
To gain ultimate strength, base metal should be ground down until its bare surface appears. Because mill scales can also increase the chance of metal breakage.
When you are welding two metals, usually welders only run a single bead around the joints. And in most cases, a single bead is more than enough to hold the metals together.
However, much stronger tensile strength can be achieved by stacking the beads. Due to multiple stacks, the volume of the weld increases.
So if you want to check the strength of stick welding, you can also observe the layers of beads stacked on the metal. This is one way to ensure maximum strength but there is one thing you should be careful about.
Removing slag after the first pass
Before stacking the second bead, slag should be removed from the surface. When the flux is burnt from the rod during welding, slag is formed. A shiny weld appears beneath once the slag is removed from the surface. This way, the welds are bound to be stronger.
And if you try to run the second bead without removing slag, it can result in “slag inclusions”. Eventually, the weld will lose its solidity.
Ductile strength and brittleness
When it comes to choosing a welding process suitable for the result we want, ductility is one of the main factors taken into account. Ductility tells us which metal or rods are best for a certain project and will give us our desired outcome.
Tensile strain is one of the main reasons that welds end up breaking and cracking. So when we apply force on a solid material or stretch it with strain, it might crack because it is not strong enough to hold that pressure and force.
These rods have high ductile strength. 7018 rods are low hydrogen rods. They can hold out against major stresses and heavy bendings. This is one of the main reason 7018 rods are used in projects that involves heavy metals.
As discussed above, these rods are used to weld thick metals because they have thick flux. So if there is a chance of bearing heavy pressure on the weld, these rods are the best option for you. Because they can prevent the weld from damage and breaking.
Stick rods like 6010 don’t have high ductile strength. They have the ability to penetrate the metal but they result in brittle welds. If a lot of stress or pressure is applied to these rods, there is a high chance that they will crack and break.
That is the reason, for heavy industrial work where thick metal is used, 6010 rods are avoided. The projects where the weld has to undergo stress and pressure, 7018 rods are the best.
Now let’s see if you can answer or not. If you are going to build a huge skyscraper, which rods will you use for this job? Just keep in your mind what we discussed earlier.
The efficiency of stick welding
One of the main problems of stick welding is its low efficiency. As compared to the other welding techniques, its efficiency is quite low.
Only 60-65% material of the electrode stick is transferred to the bead of the weld. Other 35-40% is burnt and results in the formation of slag and shielding gas. This lowers the efficiency if we are looking through the point of view of strength.
Not only this, but due to dust and smoke that is coming off as a result of welding, it becomes difficult to see the weld. Also, it becomes hard to keep the weld bead under control due to the exothermic activity.
Considering the welding environment, differences can also come in the strength of welds. Stick welding is famous for making strong welds outdoors.
A strong weld can be produced regardless of snow, wind, or rain. Whether indoors or outdoors, high tensile strength can be achieved using stick welding.
Last but most important is the hands of the welders. They can give long-lasting strength to the weld and at the same time destroy it too. Stick welding produces strong welds when done by an experienced welder.
Keeping in mind all the factors we have discussed, stick welding can result in the strongest welds that you want. Proper technique and desirable circumstances ensure strong welds with high tensile strength.