[Ultralow787]

You always hear about aluminum oxide requiring 3 times the amount of heat to melt that clean aluminum does. Has anyone got any info on the effect of oxidized steel? When welding with oxy-fuel, if you stop and then try to restart, the oxidized metal seems to take a lot more heat to get a puddle going (sometimes it is darn near impossible). I can't seem to find any detailed info on this.

[weldin mike 27]

Hey,

I have noticed that when bronze welding cast iron. Wanted to smooth out a lumpy bead but it took forever to melt. gave up in the end.

On the steel it seems strange because science tells us that steel oxide melts /burns at a lower temp than steel. Crazy. Do a test where you grind or file the end of your last run to shiny and see if that helps.

Mick

[jedison]

i am actually currently going to try different methods to figure this out too as i have been doing some research on this myself and i was not able to find the proper answer and detail to this maybe it really takes someone to actually try things out. i will keep you posted when i am done and see what happens/which is a more effective method on this.hope my learning are well enough to be able to go through the process successfully as i am really a curious beaver. wish me luck!:)

[Ultralow787]

I've recently found that even on new steel, it takes an extreme amount of time/heat to melt. It makes no sense because the flame temp is close to 6,000 deg.F and the steel is supposed to melt around 2,500 to 2,700 deg.F. I tried grinding off the heavy mill scale and it still take way too much heat to melt. Very strange!