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P-added high strength IF steel M250P1 is widely used in vehicle body and safety parts because of its good mechanical performance and forming properties.Experiments of high power laser welding of 4.8 mm thick P-added high strength IF steel M250P1 is performed by using a 12 kW CO_2 laser.In order to investigate the effects of phosphorus in high strength steel on the quality of welding,the Cupping and tensile tests,optical and SEM energy dispersive spectrometer analysis have been done on three welded joints.Some results have been obtained below.In the given welding parameters,the welded joints show good tensile and forming properties.However,it has been also found that the cracking is easy to occur in the fusion zone of welded joint during deformation.Some research works have been done.The results show that the fast cooling of fusional metal leads to the phosphorus microsegregation in the fusion zone because of relative low diffusion rate of phosphorus,which brings about the poor toughness of welded joints.
P-added high strength IF steel M250P1 is widely used in vehicle body and safety parts because of its good mechanical performance and forming properties. Experiments of high power laser welding of 4.8 mm thick P-added high strength IF steel M250P1 is performed by using a 12 kW CO_2 laser. Order to investigate the effects of phosphorus in high strength steel on the quality of welding, the Cupping and tensile tests, optical and SEM energy dispersive spectrometer analysis have been done on three welded joints. .In the given welding parameters, the welded joints show good tensile and forming properties. However, it has been found that the cracking is easy to occur in the fusion zone of welded joint during deformation.Some research works have been done.The results show that the fast cooling of fusional metal leads to the phosphorus microsegregation in the fusion zone because of relative low diffusion rate of phosphorus, which brings about the poor toughnes s of welded joints.