Which property is critical when welding high strength materials in service?

When it comes to welding high strength materials, low hydrogen content is critical due to its significant impact on the performance and integrity of the welded joint. High strength materials are often more susceptible to hydrogen embrittlement, which can lead to premature failure. Hydrogen can enter the metal during the welding process, particularly if moisture is present or if the consumables have a high hydrogen potential. This can create internal stresses and cracks in the heat-affected zone (HAZ) and can ultimately compromise the mechanical properties of the material.

Controlling hydrogen content is essential to ensure that the weld does not become brittle and maintains the desired strength and ductility of the original material. Techniques such as using low-hydrogen electrodes, preheating the base material, and controlling the cooling rate can help reduce hydrogen levels and enhance the quality of the weld in high strength materials.

The other properties mentioned, while potentially relevant in specific contexts, do not directly address the critical issues posed by hydrogen in welds of high strength materials.