MANUFACTURE FOR ZIRCONIUM ALLOY-MADE THIMBLE TUBE FOR PRESSURIZED WATER REACTOR CONTROL ROD GUIDE TUBE

摘要

PROBLEM TO BE SOLVED: To economically manufacture a thimble tube with superior dimensional accuracy and good surface characteristics by using a swaging machine provided with a cemented carbide-made mandrel and die. SOLUTION: After obtaining a blank tube 1 of which the outer diameter and thickness are nearly equal to the dimensions of the large diameter part 1a of the product by cold rolling, a small diameter part 1b or one provided with a large diameter part 1a in the middle is formed at one end by using a swaging machine provided with a cemented carbide-made mandrel 6 and die 4. Here, by driving a tube rotor 3 and a fabrication head 5, each is rotated in opposite direction or the same direction, and a moving dolly 2 is moved in the direction of the arrow. Then, the die 4 in the fabrication head 5 reciprocally moves towards the tube axis, reduces the outer diameter of the blank tube 1 and a small diameter part 1b is formed. The die 4 arranged inside the fabrication head 5 and the mandrel 6 inserted in the blank tube 1 must be cemented carbide-made.