Re-phrase post for Multiple PQRs supporting one WPS for hardfacing

[newweldeng09]

QW-200.2, Par. (f) states that one WPS may cover several variable changes as long as a supporting PQR exists for each essential...variable. Taking this into account, I have two PQRs for the PTA process with the following essential variables:

1st PQR: preheat- 500F; interpass- 800F; torch orifice diameter- 3/16"; powder feed rate: 11.3 g/min; travel speed: 3.75 IPM; Current: 170 amps.

2nd PQR: 600F; interpass: 900F; torch orifice diameter: 1/8; powder feed rate: 15.1 g/min; travel speed: 2.75 IPM; current: 130 amps.

The subsequent WPS would be qualified for 400F min. preheat (QW-406.4); 900F max. interpass; 1/8" and 3/16" torch orifice diameters; 11.3 +/-10% and 15.1 +/- 10% powder feed rates; 2.75 -15% to 3.75 +15%; 130 +/- 10% and 170 +/- 10% amperage.

Is this the proper interpretation of the above statement?

 

[Fizza453]

I assume impact testing is a requirement in your case, with the said two PQR's you cannot write WPS with 400F (minimum) because Code does not allow to reduce preheat more than 100F. Similarly, check all others essential and supplementary essential variables this way if applicable.
If impact testing is not a requirement, then it is okay as you have done.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[newweldeng09]

Impact testing is not a requirement for hardfacing (QW-257.1). The first PQR was qualified with a 500F preheat, the second to 600F. Am I allowed to extend to 400F min. on WPS based on 1st qual.?

 

[Fizza453]

If you are writing a WPS with supporting 1st PQR, then are allowed to write 400F.
If you are writing WPS with supporting PQR's 1 and 2, then you cannot write WPS with 400F as a preheat, because essential variable QW-404.6 is not satisfied.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN