Here is a link to an AWS Research Paper that I found that addresses preheat requirements for "unknown" grades of carbon steel.
I am not sure I agree with all of the data, but it does tend to fall on the conservative or "safe" side.
For 1022, using the formulae, I calculate a preheat of 647 F, but the paper uses the catch all of linking thickness to the need for preheat.
The real world need for preheat might be more of a "motherhood" issue. From a practical standpoint, it might not always be necessary. But, for some applications, it might be wise to ask what the odds are of the weld being subject to an impact load in a hardened condition.
Here is the link to the article. Note that if the literal carbon content for 1022 is used to calculate CE the result is irrational since it is not possible to take the square root of a negative number. He gets around this by suggesting use of a CE of 1.0 which is why I say this data might be overly conservative. LOL
http://www.aws.org/wj/supplement/WJ_2008_11_s273.pdf