On the role of interlayer cooling time in wire laser cladding of 316L: microstructural, mechanical, dimensional and residual stress analysis

Wire laser cladding (WLC) is a laser-based additive manufacturing process that deposits metal wire onto a substrate to build up coatings or fully functional parts, offering high material efficiency, low dilution, and strong mechanical properties. In WLC, an optimized layer deposition strategy and toolpath are essential to ensure geometric accuracy, minimize defects, and achieve high-quality mechanical properties. This study investigates the effects of interlayer cooling time (ICT) as a high-impact parameter on the mechanical properties, residual stress distribution, and microstructural characteristics of 316L stainless steel components manufactured using WLC. Multi-layer samples with ICT values between 2 and 60 s were fabricated and evaluated through tensile testing, residual stress analysis, optical microscopy, and SEM-based fracture surface examination. The results show that ICT strongly influences the thermal history of the process, which affects both mechanical properties and microstructural integrity. An ICT of 17 s yielded the improved true ultimate tensile strength (up to 27%), the decreased residual stress levels (up to 60%), and the most refined grain structure with an average grain size of 17 μm. In contrast, both short (2 s) and long (32 to 60 s) ICTs caused thermal imbalance, grain coarsening, and elevated residual stresses, resulting in reduced strength or ductility. SEM analysis confirmed ductile fracture in all samples, with the finest and most uniform dimples observed at 17 s. These findings contribute to a better understanding of how ICT governs process–structure–property relationships in wire laser cladding of 316L stainless steel.