PT. Rire Sanjaya Sakti has grown to be the leader supplier of heat treatment equipment and PWHT(Post Weld Heat Treatment) service, offering electrical and gas or oil fired heat treatment system. Our services include local PWHT(for pressure vessel, storage tank and pipe), pre heating local,PWHT by electrical heating system,PWHT internal Firing by Gas,PWHT by internal firing by oil,PWHT by Fix furnace (electrical, oil firing, gas firing)
Local Post Weld Heat Treatment (PWHT) is usually performed for tempering and relaxation of residual stresses. Circumferential weld seams can be post weld heat treated by heating a band around the weld. Many factors have an influence on PWHT procedures and the heated width is the most important parameter controlling the effectiveness of local PWHT. However,the determination rules of this parameter are very different in the different codes.
Pre – Heating
Pre- Heating is an in-situ electrical heating technology that uses electricity and applies it into the pipe before welding process. Element will be increase temperature and to maintain weld ability of base material and to avoid hot cracking when welding process.
In this case, the workpieces are heated by gas firing through nozzles. Vessels of suitable dimensions and arrangement of openings can be post weld heat treated by internal firing. It is not advisable to post weld heat treat vessels that contain internals in this manner. The outside of the vessel must be completely encased in insulating material, and again, at least a 12 point temperature recorder is advisable.
A fixed furnace usually consists of a rectangular box made from heat resistant materials in which are embedded electric resistance elements. Doors open at each end and a travelling bogie allows for loading and unloading of the charge. Furnaces are capable of heating to 1200Â°C and can normalize and anneal as well as stress relieve. This method is traditional and well known to most people in the fabrication industry.