PRODUCTION OF T-SHAPE PIPE JOINT

摘要

PURPOSE:To prevent the end of a branch pipe from being broken and to stably mold a branch pipe part, by using a steel plate having specific ferrite grain size number and executing burring work in a specific 2-phase area or single phase area. CONSTITUTION:A steel plate which is produced by controlled rolling and has a uniform texture with >=10 ferrite grain size number (ASTM) is prepared as a blank plate and the blank plate is heated by hot working in 500-800 deg.C temperature range to obtain a half-finished product 13. A lower hole 14 is drilled on the product 13 and the drilled product is heated up to a 2-phase area consisting of ferrite and austenite or an austenite single phase area and hot burring work is executed in the temperature range. A master body 13'' (a half-finished product with a branch pipe) of a piece on the branch pipe side which is obtained by the burring working is welded to connect with master body 18 of a piece on the master pipe side to complete a master pipe part 1 and then cut finishing is applied to both the pipe ends of the master pipe and the branch pipe to obtain the titled product.