QW-410.47 explanation

[1973Patrick]

Hello,

can someone explain me what the meaning is of the text below?
QW-410.47 is an essential for PAW hardface overlay and I have to mentioned this parameter in the WPS.What I do not understand is the rate of cooling temp from the fusing temp. and a change in fusing temp.

QW-410.47 A change of more than 10% in the fusing
temperature range qualified. A change in the rate of cooling
from the fusing temperature of more than 50°F/hr
(28°C/hr), a change in the fusing method (e.g., torch,
furnace, induction).

Thnx! Patrick

 

[Duwe6]

http://www.cwaevents.org/events/weld-overlay-wear-protection

Start here [Google is your friend ]

Cooling rate on a hard overlay is critical - too fast a rate and the hardfacing will rip itself apart. Change in fusing temp changes the ammount of dilution, making it critical too. Too much dilution, it becomes softer than intended; too little dilution, it falls off the base metal - it was a braze, and failed to weld itself to the base.