Strain distribution vs strain evolution during solidification cracking CTW test for laser beam welding of 1 mm austenitic stainless steels
- Laser welding is a widely established manufacturing process across many industrial sectors. However, solidification cracking and the weldability of materials have remained contentious issues for many years, particularly concerning the causes of hot crack formation.
The local distribution of total strain was measured in close proximity to the solidification zone during laser welding of AISI 304 and AISI 310S stainless steels, using the Controlled Tensile Weldability (CTW) test. In this setup, 1 mm thick weld coupons were subjected to a defined external tensile load during welding. Mechanical loading parameters were varied by adjusting the strain rate and ultimate strain level to identify the critical conditions that lead to solidification crack formation along the weld seam centerline. Using Digital Image Correlation (DIC) and the optical flow method [1], we estimated the local strain distribution at the surface near the molten pool and tracked its evolution across severalLaser welding is a widely established manufacturing process across many industrial sectors. However, solidification cracking and the weldability of materials have remained contentious issues for many years, particularly concerning the causes of hot crack formation.
The local distribution of total strain was measured in close proximity to the solidification zone during laser welding of AISI 304 and AISI 310S stainless steels, using the Controlled Tensile Weldability (CTW) test. In this setup, 1 mm thick weld coupons were subjected to a defined external tensile load during welding. Mechanical loading parameters were varied by adjusting the strain rate and ultimate strain level to identify the critical conditions that lead to solidification crack formation along the weld seam centerline. Using Digital Image Correlation (DIC) and the optical flow method [1], we estimated the local strain distribution at the surface near the molten pool and tracked its evolution across several characteristic zones—before, during, and after the application of mechanical loading. The results revealed that solidification crack formation coincides with regions of high plastic deformation within a critical temperature range. Furthermore, we identified a clear relationship between strain rate and both crack initiation probability and maximum local strain. Importantly, neither strain rate nor maximum strain alone is sufficient to predict cracking; instead, their combined effect must be considered to accurately assess hot cracking susceptibility.…

