The carbon content of low alloy steel is roughly the same as that of 304L stainless steel pipe, generally not more than 0.25%. However, due to the addition of a small amount of alloying elements, the welding performance of the steel is better than that of the 304L stainless steel pipe. Different alloying elements have different effects on the weldability of steel. In order to facilitate comparison, it is usually converted into a considerable amount of carbon content according to different ratios, which is called carbon equivalent. According to the recommendation of the International Society of Welding, low-alloy steel can use the following formula to calculate the carbon content and evaluate its weldability
CE=<;CMn/6. (CrMov)/5/15>;%
When the required carbon equivalent CE is less than 0.4%, the weldability of the steel is excellent, and the welding technology is basically the same as that of the 304L stainless steel pipe. No special measures are required. When the CE decreases = 0.4~0.6%, the weldability of the steel is limited, and the welding needs to be preheated before welding. When the technical measures such as current and welding speed are CE>0.6%, the weldability of steel is poor, and more strict and complex technical measures need to be taken
In addition, the highest hardness method can also be used to evaluate the weldability of the steel. However, both of them are methods for indirectly evaluating the weldability of steel materials. If a more accurate assessment is required, a series of solderability tests are required, which will not be described here.