Welding - WTH?

Duke

Duke

Registered
Registered
Joined
Dec 30, 2018
Messages
73
I am busy upgrading my mini mill - part of which involved welding a structure from 10mm steel plates.

The base plate is about 12" by 25" and is 10mm thick.

I decided to add a couple of steel bars to the bottom of the base plate for additional support.


After welding, I discovered that the whole plate has been bent out of shape along both it's width and length.

I knew that stuff will bend while it is welded, but did not think this will happen on 10mm steel.....


Fortunately I did manage to get it bent back to within about 95% of what it was.
 
Last edited:
Nothing to do with welding or machining but many years ago when we first came to australia virtually every back yard (in North Queensland) had a wood fired barbequem
Ours didnt have a plate to cook on so I used a steel plate 36x24 inches.
It was dead flat when it went on but after the first bbq the bow in the centre was around 3 inches higher than the edges.
I left it as it was so all the fat drained off.
It is amazing how much metal will distort with a little heat on one side.
 
Stitch welding, plug welding, and moving from side to side, will help to minimize distortion. Any size metal will distort from welding. 10mm, at under 1/2" is in no way immune. Like most things, a little more experience will help you in this area. Mike
 
As the weld puddle cools, it shrinks, SIGNIFICANTLY! You have just learned one of the most important lessons for any weldor, very similar to the first time you mill off one side of a piece of cold-rolled. In exactly the same way, you learn to anticipate and plan accordingly. No matter how firmly you clamp the parts, they are going to move.
 
savarin said:
Nothing to do with welding or machining but many years ago when we first came to australia virtually every back yard (in North Queensland) had a wood fired barbequem
Ours didnt have a plate to cook on so I used a steel plate 36x24 inches.
It was dead flat when it went on but after the first bbq the bow in the centre was around 3 inches higher than the edges.
I left it as it was so all the fat drained off.
It is amazing how much metal will distort with a little heat on one side.
Click to expand...

In the same vein, my friend built a large wood stove from the end of an explosion-proof conveyor housing that had to be shortened. He made the top plate from 12 ga. 304 S/S. When the stove was hot, that plate would dish down almost 2 in., returning to flat (more or less) when it cooled. I suggested he weld a ring in the middle and attach linkage to a needle on the mantle, creating a large temp gauge.

Four decades ago, I built a heavy stainless steel fire grate for the cave I used to live in. I designed it to allow the 1/2 diameter rungs to expand and contract by only welding them at one spot in the middle. It is still flat, and sufficiently heavy that no one has bothered to steal it.

All steel moves with heat, stainless moves even more.
 
Slightly on topic, are there tables available with expansion rates for various metals?


Sent from my iPhone using Tapatalk
 
DavidR8 said:
Slightly on topic, are there tables available with expansion rates for various metals?
Click to expand...

Thermal Expansion - Linear Expansion Coefficients

Linear temperature expansion coefficients for common materials like aluminum, copper, glass, iron and many more.
www.engineeringtoolbox.com www.engineeringtoolbox.com

also has a calculator.

Google "coefficient of thermal expansion" and you will find many versions.
 
Thanks @RobertB


Sent from my iPhone using Tapatalk
 
savarin said:
Nothing to do with welding or machining but many years ago when we first came to australia virtually every back yard (in North Queensland) had a wood fired barbequem
Ours didnt have a plate to cook on so I used a steel plate 36x24 inches.
It was dead flat when it went on but after the first bbq the bow in the centre was around 3 inches higher than the edges.
I left it as it was so all the fat drained off.
It is amazing how much metal will distort with a little heat on one side.
Click to expand...
Did you slip a shrimp on the Barbie?
 
You must log in or register to reply here.
Back
Top