Does your application with the line pipe steel API 5L grade X52 specify impact requirements - For example per the API 5L specification does the seamless or ERW grade X52 have an SR5 supplementary requirement? If not, you could use this procedure.
If the API 5L grade X52 requires impact testing for service, your procedure above would not work because you have not qualified to a specific Group No. When you qualify weld procedure specifications to ASME Section IX, in addition to the P-No or S-No, the Group No also becomes an essential variable.
One point of clarification that I need to mention is that API 5L grade x52 does NOT fall under any ASTM specification for equivalency of a P-No to an S-No. The grade X52 has a reported UTS of 66 Ksi and YS of 52 Ksi.
The P-No 1 WPS above cannot be used for welding this material for applications under ASME B31 Piping Code. You would need to qualify a WPS for the API 5L grade x52 material.
ASME IX does now cover B31 materials, but they are listed under S Numbers instead of P Numbers. Per ASME Table QW/QB-422, API 5L Grade X52 is an S No. 1, group 1 material. Since your WPS was qualified on P No. 1 material, it would be suitable for welding non-impact X52 material (it would not work the other way around though- qualifying on S-1 material, then welding P-1 material). Since you have impact requriements, your original qualification material would also have to be group 1, but you do not state whether it is or not.
GRoberts;
Agreed on the use of this procedure for non-impact applications in B31 Piping Code. The last sentence in my second post is confusing because I had forgot to type the word "impact" for applications under B31 Piping Code. Good catch.