Dirtman55, thanks for the response, if you have any more questions i can give more info. Now from my delvings in my text books it appears that the glass transition temperature is quite variable with the material that we are looking at. For instance aluminium is far more susceptible to temperature than a high strength steel. Now in the early days of manufacturing, in the 1940-50's there were quite a few accidents with ships that split in half due to the steel entering this transition range. Nowadays there has been far more research in metallurgy and the strength transition for steels will not be as dramatic.
All steels will become more brittle as they cool down, but if you are using a high quality, high strength steel, it will be more stable over a large temperature range. I think i would only worry about cheaper machinery, from second rate companies. The quality of the steel that they may be using could inferior to more complex and modern steel alloys, used in more expensive equipment.
Now another factor could be the welding rods that are used too, the steel plates may be ok, but if they are using an incorrect grade welding rod it could fail prematurely in colder conditions.
A good example is a hard facing welding rod, try and weld to bits of steel together, and then load it up until the weld fails completely. Now re-weld with a low hydrogen rod, or high strength welding rod and repeat the process, you will find that it will take a lot more force to break the weld seam.
This is because the hardfacing is very hard, but at the same time it is very brittle. The low hydrogen rod isn't as hard, but has much greater structural strength.
Hope that explains a little
Any questions feel free
Cheers Alex
