Cooling is an area of heat treating that is sometimes taken for granted and not given any serious consideration. Many plants startup and when approaching or exceeding the design production rates find that the exiting product is too hot to handle properly. “Fixes” are installed which usually means adding fans to a process and degrading quality of the finished product. When designing a plant, ESG spends considerable amount of time modeling the cooling portion of the process to get it right the first time.
Why is rotation needed?
When the pipe exits the temper furnace the cooling is relatively fast. Non uniform cooling on the pipe will cause stresses as those cooler sections and they start to contract. In the best case it instills stresses in the pipe body that it wants to relieve. In the worst case, it can cause a tube or pipe to bend. This is why in many operations a gag straightener is present to take care of these immediate problems. A better solution is the ESG rotating disc table.
The fast rotation of the ESG disc table allows natural draft cooling to take place, but it is uniform throughout the circumference of the pipe. The disc contact point, unlike a rail, is narrow and will heat up and not cause point of contact cooling like a drag chain table. The table also has an added benefit, if a tube already has a bow, the table will allow the piece to straighten as it goes through the upper end of the cooling curve. The results we have seen is consistently straight pipe that does not need to go through a straightener.