Influence of Grain Refinement on the Weld Zone of High-Strength Steel Pipes

The microstructural evolution in the weld zone significantly affects the strength and toughness of welded pipes. Factors influencing grain refinement include:

• Welding Speed and Heat Input: Higher heat input leads to coarser grains, reducing impact resistance.

• Alloying Elements (e.g., Ti, Nb, V): Microalloyed steels form finer grain structures, improving weld strength.

• Thermomechanical Processing: Controlled rolling and accelerated cooling refine grains in the Heat-Affected Zone (HAZ).

• These factors are critical in producing high-performance welded pipes for offshore drilling and high-pressure gas transmission.