Preheating can assist the welding penetration on materials with high thermal conductivity such as thick aluminium sections, or even some steels.
This reduces the heat sink affect (rapid cooling) of the deposited weld by the surrounding cold metal. Preheating also significantly reduces the rapid cool down of the item post welding.
Contrary to many beliefs, it is difficult if not impossible to overheat metals but many metals (such as carbon steels) can become brittle if cooled rapidly. They can also lock in post weld stresses that can compromise the engineering qualities expected, resulting in costly weld fails and repairs.
Preheating builds up heat in the metal and it takes longer for it to cool. In effect, preheating is also a portion of the post heating formula.
In most welding code applications, carbon steels and some other metals require preheating prior to welding to be in compliance.
There are many different treatments that could be considered. Variables such as material thickness, size of the job, project timeline and budget, as well as level of knowledge of the personnel on the job. Take a look at our analysis of the different processes here.
What are the advantages of buying Used Induction Heating Machines over New?
Quite simply PRICE & Availability – especially when buying a recognised brand such as AEC – Miller & Cooperheat.
AEC Technology of Italy are a leader in the market of equipment and accessories for the furnace heat treatment of the welds. In 1973 AEC Industrial Electronics patented the equipment called “Thermocontrol” to run non-furnace preheating, post-heating and stress relieving of welded joints with the resistance method.
AEC’s Low Tension Resistance Machines have been especially designed for pre-heating and stress-relieving heat treatments.
These machines, produced in a strong stainless steel framework, spray painted, have been equipped with wheels to facilitate small movements and eye-bolts for their lifting. Input tension of the heating elements, varying between 0-90V, makes these machines particularly fit for the use on site or in the factory.
The small dimensions of the Thermocontrol R/6 BT 81 model allow the use of several machines in series also on difficult sites like naval or offshore ones.
The operations of the machine are completely automated.
The series of machines available goes from an effective power between 27 and 216KVA divided on n. 3-6-12 independent outputs.
Westermans International Limited has a quantity of Thermocontrol AEC Low Tension Resistance machines available from stock, Miller Induction Heating Systems and Stork Cooperheat Pre Heat Treatment Power Sources, click here for details.
Visit our web site http://www.westermans.com or contact Craig Westerman by email email@example.com or telephone +44 (0) 116 2696941 for a quotation TODAY.
Follow this link to find out more about Heat Treatment of Welded Joints available on TWI’s web site under Technical Knowledge.