| 摘要 |
PURPOSE:To obtain a ferritic stainless steel pipe having a weld zone which is highly tough and ductile in the stage of welding the opposed edge parts of a steel plate formed to a pipe shape by a laser beam by regulating respectively the quantity of heat input, the min. beam diameter and focal depth of the laser beam, etc. and regulating the width of a weld bead. CONSTITUTION:The opposed edge parts of a ferritic stainless steel plate formed to a pipe shape are welded under the following conditions by using a laser beam 6: The following conditions are set between the thickness (t)mm. of a sample material 1 and the quantity of heat input P (J/mm.<2>) of the laser beam per unit welding length of the laser beam 6 and the unit thickness of the steel plate to be welded expressed by PL=P/vt. The conditions are set at 30 J/mm.<2=Pt<=60 J/mm.<2>, 0 (surface of the sample material)<=x<=0.5t(a<=0.5t), 2t<=l. The weld zone of the ferritic stainless steel is made highly tough and ductile by regulating the width of the weld bead in the above-mentioned way. In the figure, 9 denotes a laser source, 7 a lens, 8 a focus, (a) a min. beam and (l), a focal depth, respectively. |
