Do you want to know more about our heat treatment methods? We will explain more about the Post weld heat treatment, or PWHT, method on this page.
What is post weld heat treatment?
Post weld heat treatment (PWHT) is a regularly performed, controlled process in which an object is being reheated to a temperature below its lower critical transformation temperature. It is held at this specific temperature for a certain amount of time. This process is being done after the object has been welded. This is done in order to ensure that the material will retain its strength. It will reduce residual stresses by heating the material to a specific temperature and then gradually cooling it. Moreover, it prevents hydrogen induced cracking from happening by post heating the object immediately after completion of the weld. Besides, it will enhance material strength and the treatment can also function as a method of hardness control. For example; within the different industries of oil, gas and petrochemicals, it is mandatory to ensure a safe design. Post weld heat treatment is a form of establishing those mechanical properties.
Incorrect use and requirements
When PWHT is being performed incorrectly, residual stresses can exceed the material its design limitation leading to welding failures, cracking potential and increased chance on fractures. Whether an object should undergo PWHT and how long the treatment should last, depends on the alloying system, previous undergoing treatments and the materials the object is made of.
Delta Heat Services is a qualified and experienced specialist in heat treatment. Next to that, are we specialised in preheating, annealing, post weld heat treatment, bake- and dry-outs and shrink fittings. We offer a broad range of services and combine our knowledge with technologies. Also, we have a excellent service as we are being flexible and customer-oriented. We want to provide the best solutions for every heat treatment enquiry. Delta Heat Services operates internationally and is located in the Netherlands, Belgium Portugal, Romania and the Caribbean.
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