Welding Q&T P1 Steels
Welding Q&T P1 Steels
(OP)
We are manufacturing a vessel/pipe fitting from triple certified material, i.e. SA105 / SA350-LF2 Class 1 / ASTM A694 Grade F46. Our Regulatory Authority (R.A.) has stated that they will register the fitting in the Normalized only condition. Our Material Supplier says to consistently achieve the mechanical properties of all three material specifications, we should consider Quench and Temper heat treatment. Our R.A. says that if we go with Q&T, we must PWHT to the tempering temperature, paying close attention to our heat input, regardless of material thickness. We want to use Q&T material in the as-welded condition, per our WPS.
I talked to a couple of Welding Engineers and they said the requirement for heat treatment of P1 materials is based on material thickness, not the heat treatment condition of the base metal. Our WPS (P1 Group 1 & 2 to P1 Group 1 & 2) doesn't list base metal heat treatment as a variable.
I can't seem to get a satisfactory response from our R.A. as to the reason behind the PWHT requirement. As it is totally possible I'm missing something, does anyone know where, in any vessel/piping code, where PWHT is a requirement for Q&T P1 steels, regardless of thickness?
I talked to a couple of Welding Engineers and they said the requirement for heat treatment of P1 materials is based on material thickness, not the heat treatment condition of the base metal. Our WPS (P1 Group 1 & 2 to P1 Group 1 & 2) doesn't list base metal heat treatment as a variable.
I can't seem to get a satisfactory response from our R.A. as to the reason behind the PWHT requirement. As it is totally possible I'm missing something, does anyone know where, in any vessel/piping code, where PWHT is a requirement for Q&T P1 steels, regardless of thickness?





RE: Welding Q&T P1 Steels
yours,
stanweld
RE: Welding Q&T P1 Steels
RE: Welding Q&T P1 Steels
Weldstan: The material is essentially SA350-LF2 Class 1 with 46 ksi minimum yield. That covers all three grades. The A105 will be manufactured to a fine grain practise to satisfy the requirements of SA350.
Metengr: I agree normalizing is a better way to go, but the higher yield requirements puts a little more pressure on the forging manufacturer to get the yields in the normalized condition - something I'm sure gets factored into the price. It's the PWHT requirement from our R.A. that's puzzling me and both responses help. Thanks.
RE: Welding Q&T P1 Steels
RE: Welding Q&T P1 Steels
Whenever you are to perform PWHT on welding that the base metal is in "quenched and tempered" condition you shall pay special attention since you may loose the "quenched-tempered" properties of the the base metal. As you know the quench-temper heat treatment is performed in order for the material to be done harder (first the material shall be heated above the upper critical temperature, then it is cooled rapidly and finally it is heated at about 600 deg C), so if you perform PWHT above the tempering temperature (about 600 deg C) you may loose the material's specific properties. Please have a look at these links that among others they clarify such an issue:
http://www.weldinguide.com/gdanastasiadis/viewtopi...
http://www.weldinguide.com/gdanastasiadis/viewtopi...
regards
wegm
RE: Welding Q&T P1 Steels