![lol :lol:](/f2/epx.png)
![lol :lol:](/f2/epx.png)
![lol :lol:](/f2/epx.png)
Frenchman from Germany...
Lets leave that there,
for CS preheat is ussually recommended to limit the risk of hydrogen or cold cracking and is based on:
Heat input
Carbon Equivalent
Hydrogen content of consumable
Thickness/Restraint.
For higher alloy martensitic steels it is in general mandatory.
SO in short, if you have qualified your procedure and proven that you can weld without preheat then it should be fine, just keep in mind though it is better to stipulate a minimum temperature as opposed to no preheat or RT as this will vary between teh seasons.
Then as stated by the Gentlemen above, for ferritic material you could rarely go wrong with applying preheat for a varietey of reasons.