Extra-thick normalizing steel plate research on welding performance of high wire energy
Microstructure and mechanical properties of the heat affected zone(HAZ)of welded AH36 normalizing steel plate that manufactured by Rizhao Steel Yingkou Medium Plate Co.,Ltd.,and the thickness is 120 mm were studied by the combination of actual high heat input gas vertical welding and submerged arc welding.The results show that when the heat input is 656.4 kJ/cm,the tensile strength of the welded joint meets the standard require-ment of the base metal,but the margin is small.The 0℃ KV2 toughness index of the welded joint can meet the standard requirements for the base material,but the impact toughness value at 1/2 thickness is lower than that of the surface.When the submerged arc welding is used and the heat input is 41.5-65.7 kJ/cm,the strength and toughness index of the welded joint can meet the standard requirements of the base material stably.There is an obvi-ous coarse-grained zone in the welded joint with a width of about 2 mm and a distance of less than 1 200 μm from the fusion line.The coarse-grained characteristics of superheated austenite are particularly obvious.The microstructure of the coarse-grained austenite consists of grain boundary ferrite+acicular ferrite+granular bainite,and the acic-ular ferrite core is promoted by the inclusion of Al-Ca-Si-Ti-Mg composite oxides.
AH36 extra thick platelarge line energy weldingtensile propertyimpact toughnesscoarse-grained region
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