There are procedures that can be followed to minimize stress relief cracking of carbon steels. They include the selection of more appropriate weld joint design, weld location, weld filler metal, and sequence of assembly to minimize restraint and stress concentrations. Many codes, including the ASME Boiler and Pressure Vessel Code, define when post-weld heat treatment is to be done. There are also published post-weld heat treatment guidelines based on the thickness and highest carbon content of the base metals to be joined. I suggest you consult one of several references for more information such as the ASM Specialty Handbook "Carbon and Alloy Steels" or the AWS "Welding Handbook".