A comparison of methods for estimating the weld-metal cooling rate in laser welds
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Microstructural transformations in 304 L stainless-steel welds as a function of welding parameters were studied using a high-power continuous CO2 laser. The experimental results can be represented by the relation λ1 = 40 V−1/2 where λ1 is the primary dendrite spacing in μm and V is the welding speed in mm s−1, for different laser powers and two sample thicknesses. The cooling rates estimated by different methods have been found to be in the range 102 to 3 × 103 Ks−1, and the temperature gradients are in the range 102 to 9 × 102 K cm−1. The experimental results are shown to be in very good agreement with recent dendrite-growth models. An analogy is presented between the cooling rate during melt spinning and laser welding.
KeywordsWelding Cool Rate Temperature Gradient Laser Power Material Processing
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