Has anyone read any books that describe the penetration depth ranges of various welding methods? If so, could you recommend a few?

The welding penetration is related to the welding current, welding voltage, and welding speed. I think you could try conducting some experiments: take a 10mm thick sheet of metal and carry out welding tests, keeping two of these factors constant, adjusting the other factor for a specific welding method, and then cutting the sheet open to observe the penetration level, which will provide a more intuitive view. For example: studying the relationship between the penetration depth in submerged arc welding and current, voltage, and speed. For example, with a fixed welding voltage of 30V and a welding speed of 50 cm/min, the welding current can be adjusted from 300A to 600A, with increments of 50A or 100A per adjustment step. It is possible to determine how much the penetration depth increases for every additional 50A or 100A ； Additionally, the welding voltage or welding speed can also be adjusted. Overall, the welding current affects the penetration depth ； Welding voltage affects weld width ； Welding speed affects both penetration and weld width. Of course, you also need to consider the impact of other factors: such as people, machines, and the condition of weld cleaning, etc. In my own opinion, since I couldn’t find any relevant books, I had no choice but to use these basic experimental methods to understand it. It’s quite useful for myself.

This is related to factors such as the welding method, welding materials, welding speed, heat input, and the diameter of the weld rod. Generally, with manual arc welding, the penetration depth in carbon steel is around 1–2 mm, while it is 4–6 mm when using submerged arc welding. Different materials require different welding parameters, which in turn result in varying penetration depths.