Today at work I laid the floors on the Kamaz trailer. These are sheets of metal with a thickness of 2 mm and dimensions of 1250 by 2500 mm. We will weld the sheets with an overlap of 30mm on top of each other. We weld 5 such sheets together.
Here it will overlap two sheets. The first rule is that the overlap should be tight, the upper sheet is well pressed against the lower one, otherwise, during welding, the probability of burning the edge of the upper sheet will be much greater.
Let me show you an interesting analogy right away! It's like a fungus. Leg-electrode, head-weld in section. See what that means, the center has the deepest weld penetration in the metal. The farther from the center, the less penetration of the weld into the metal.
Therefore, you cannot tilt the electrode so that it looks axially at the edge of the top sheet. Here's how in this photo. Otherwise, the edge of the top sheet will quickly burn out during welding. And we need to weld qualitatively with the bottom sheet. See what we're doing.
When we weld, we direct about one third of the coated electrode to the top sheet, and two thirds to the bottom. Then most of the arc energy interacts with the lower sheet and we do not burn the edge of the upper one.
The very angle of inclination of the electrode from the vertical is small. Between 45 and 90 degrees from vertical. That is, we will only slightly tilt it from the vertical position.
If you follow all these recommendations, then the weld will turn out to be one third on the top sheet, and two thirds on the bottom. We do not burn the edge of the top sheet, but weld it well with the bottom sheet. Exactly what is needed.
Another important point. Since the length of the overlap is large, 2500 mm, so that there is no strong deformation, it is necessary to cook in a reverse-stepped manner. What it is?
Mark the middle of this overlap. And we will make all the seams towards this middle of the connection. In the photo, the direction of welding the seams is shown with arrows. This will deform our connection less.
I cooked with electrodes 3 mm with rutile coating, grade OK-46.
The welding current was set at 90 amperes.
I work with the Russian Torus 200 inverter. This is our domestic honest ampere welding machine - good power reserve. You don't need to work to the limit, as with Chinese devices. I recommend reading reviews about him on the Internet, you will not be disappointed