TECHNICAL MANUAL - Sharq.biz

welding cycle at double pressureWhen pipes and/or fittings have wall thicknesses higher or equal to 20 mm,the standard UNI 10520 foresees that it is possible to use alternatively to thestandard cycle (with single pressure), also a welding cycle at double pressure,here below described.(P 5 + P t )Y(P 1 + P t )1 2 3 4 5 6 7(P 6 )(P 2 )t 1 t 2 t 3 t 4 t 5 t 6 t 7XIn this case, the heating plate temperature, the pressures P 1 (Phase 1) and P 5(Phase 5) and the pressure P 2 (Phase 2) remain unchanged with respect to thestandard cycle, so as unchanged are the ambient conditions, the buttfusionmachines characteristics, the preliminary controls and the welding preparation.Also in this case, to pressures P 1 (Phase 1) e P 5 (Phase 5) it is necessary to addthe drag pressure P t pointed out as in the standard cycle. This is not valid forpressure P 6 (Phase 6), where the surfaces at contact must be subjected to apressure equal to:(0,05 ± 0,01) N/mm 2The welding parameters used for the jointing operation must be recorded in aproper report.32