If a self-taught person in welding needs to weld thick metal. Why such welding cannot be done with a wide seam and in one layer

  • Nov 25, 2021
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If a self-taught person in welding needs to weld thick metal. Why such welding cannot be done with a wide seam and in one layer

I greet everyone on the channel for self-taught garage and summer cottages in welding and locksmiths.

Here, we share work tips with beginners to shorten their journey to normal results. We do not burden us with complex information on welding GOSTs, but we try to translate everything into simple language with memorable examples.

If a self-taught person in welding needs to weld thick metal. Why such welding cannot be done with a wide seam and in one layer

Welding work on your site or in the country involves most often the welding of structures from a shaped pipe. A profiled pipe is a thin-walled material, everything is simple - you can join pipes before welding without a gap, anyway, at a thickness of up to 3 mm, and so everything will boil well and melt. Well, you can make a small gap of 1-1.5 mm if in doubt.

Welding with an electrode itself is not particularly difficult here either. Who can, cooks without interruption with minimal oscillatory movements of the electrode or absolutely without hesitation. If there are burn-throughs, cook with frequent separation, point by point.

But sometimes you have to cook structures made of thick metals. Thick are, let's say, glands thicker than 5 mm. What mistakes can a beginner make here?

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Here you have to make bevels of the edges - this means sharpening the chamfers. This is why they do it. The weld seam must melt the metal to its full thickness, without chamfering this will not work, the seam will be welded only on the surface.

RECOMMENDED SEAM WIDTH DEPENDING ON METAL THICKNESS
RECOMMENDED SEAM WIDTH DEPENDING ON METAL THICKNESS

If the metal is thick, then a beginner may mistakenly think that a wide, thick seam needs to be welded here. It seems that these seams are tighter.

On the contrary, here it is better to make several layers of narrow seams, so the connection will be stronger.

Why will it be more correct and stronger this way? Here's a funny analogy, look.

A wide one-layer weld bead when welding thick workpieces can be compared to a milk tooth in children! There is practically no deep root, which means that it does not hold on so tightly.

But a permanent tooth will have powerful roots that go quite deep and therefore hold on very tightly.

Plus, the upper layer anneals the lower one, thereby improving its structure and mechanical properties.

So welds in several layers will be like solid permanent teeth! Such a connection will be strong and reliable.

So we do everything right. We remove the chamfers from the edges to be welded, we pass the first seam without oscillatory movements with the electrode, remove the slag and you can even walk with a grinder to grind this seam.

And now we make another layer of the seam, or a few more, depending on how thick. Such tables are available on the Internet.

That's all, such a seam will be stronger than the base metal of the structure.