| 摘要 |
<p>PURPOSE: To relieve the thermal stress of a weld zone by interposing a short tube of different coefficient of thermal expansion between end parts of first and second tubes to achieve the welding. CONSTITUTION: When the end part of an invar first tube is concentrically butt- welded to the end part of a SUS304 second tube for example, a 9% Ni steel short tube 3 is concentrically interposed between the end part of the first tube 1 and the end part of the second tube 2 to weld the end parts of the first and the second tubes 1, 2 to each end part of the short tube 3 respectively. The coefficient of thermal expansion of invar of the first tube 1 is 1.5×10<-6> , that of SUS304 of the second tube is 15.2×10<-6> , and that of 9% Ni steel of the short tube 3 is 9.2×10<-6> , and the coefficient of thermal expansion of the third tube 3 is larger than that of the first tube 1, and that of the third tube 3 is smaller than that of the second tube 2. The welding cost can be reduced preferably thereby.</p> |
