Steel with a maximum carbon content of what percentage can be welded with comparable strength to the base material?

Welding of steel presents specific challenges related to its carbon content, as it significantly influences the material's properties, particularly strength and weldability. Steel with a maximum carbon content of 0.30% is generally regarded as suitable for welding while still retaining a strength comparable to that of the base material.

At this carbon level, the microstructure of the steel is more conducive to forming a strong bond during the welding process. Higher carbon content leads to increased hardness and brittleness, which can result in issues such as cracking in the heat-affected zone or weld. Thus, 0.30% carbon serves as an effective threshold to balance strength and ductility, making it optimal for applications where welding is required without compromising the integrity of the joint.

Steel with lower carbon contents, such as those in the other answer choices, may not exhibit the same level of overall performance when welded. While they may be easier to work with during welding, they do not meet the maximum carbon content criterion that ensures comparable strength in the weld joint as those with up to 0.30% carbon. This understanding clarifies why the 0.30% carbon content is defined as a critical limit for effective welding in steel applications.