We have qualified PQR with PWHT with test coupon of 22mm thickness which requires PWHT and now case exist with low thickness under 19mm in piping of carb seel with original steel phase of ferrite+ pearlite please let me know can we do PWHT on low thickness as required by PQR and similarly it is mentioned on WPS as required and if we do PWHT on low thickness does it have any adverse effects.Another important information in qualified PQR is six layers to three layers and in PWHT soaking temperature is given as 500 deg.C rather than 590 C so will it effect structurr