ON-LINE ANAERATION PERFECT SOLUTION HEAT TREATMENT METHOD FOR STAINLESS ARC WELDED STEEL PIPE

摘要

PURPOSE: An on-line perfect solution heat treatment method for a stainless arc welded steel pipe is provided to automatically heat treating the internal structural defect of a welded portion caused by the welding heat during arc welding of a stainless steel pipe. CONSTITUTION: The method comprises the steps of: (11) bending a stripe-shaped stainless steel material in the form of pipe and joining both sides of the stainless steel material together to form a stainless steel pipe; (12) processing a welded bead in conformation with the outer diameter of the stainless steel pipe; and (20) performing a heat treatment to restore the internal structural defect of the welded portion caused by the welding heat during arc welding. The heat treatment(20) comprises the steps of: (21) automatically feeding the stainless steel pipe into a quartz tube filled with hydrogen gas and heating the stainless steel pipe at 1000 to 1050°C for 5 to 18 seconds; (22) automatically feeding the stainless steel pipe into the quartz tube filled with hydrogen gas to partly heat the welded portion at 1250 to 1350°C for 15 to 60 seconds and cool the remainder portion with the filled hydrogen gas; and automatically feeding the stainless steel tube into a cooling tube containing cooling water at the ambient temperature to indirectly cool the stainless steel tube by a carbon tube contact method.