JOINT AND PROCESS FOR FORMING SAME

摘要

1485070 Forming joints; tube expanding CATERPILLAR TRACTOR CO 2 Dec 1975 [13 March 1975] 49412/75 Headings B3A and B3J To make a flange-tube joint a flange is first formed by subjecting a mixture of powdered metal and lubricant in an annular mould to a pressure of at least 4 Î 107 kg. per sq. m. The flange is removed, initially heated in a non-oxidizing gas atmosphere at between 500‹ and 1200‹ C. to remove the lubricant, further heated at between 800‹ and 1500‹ C., cooled to no more than 100‹ C. and dry machined to form at least one annular channel in its inner peripheral surface. A tube of less hard metal than the flange is inserted in the hole through the flange and the tube end expanded. The flange is preferably contacted with steam in a substantially oxygen-free atmosphere at a temperature above 340‹ C. for at least five minutes and then cooled after the dry machining step but before the tube is introduced. The initial heating is preferably carried out for five to forty minutes at 750-1000‹ C. and further heating for ten to sixty minutes at 1025-1225‹ C.