PLASTIC WORKING AND RECRYSTALLIZATION OF CYLINDRICAL CAST MEMBER HAVING PERIPHERICAL OUTER ELEVATION

摘要

PURPOSE:To enhance material quality and ultrasonic inspection property in plastically worked pipe having elevated peripheral portion, a cast cylindrical member having elevated peripheral portion is plastically deformed throughout its length, and heat treated for recrystallization while its diameter is being contracted by use of a special die. CONSTITUTION:Through back plate X, X, pressure is exerted on the whole length of a pipe with diameter D1 at elevated portion, D3 at straight portion and d inside. This forms the whole pipe in an oval shape. The elvation and its near portion are simultaneously pressed and contracted in the direction of the oval major axis by use of dies p, p. Prior to the contaction to the final diameter dimensions D'1, D'3, d', the pressing is stopped midway, and the oval shape pipe is heat treated to be followed by the next contraction. Then, the dies q, q are used to contract the subsequent portion, and similar process is continued. Each die p, p and q, q is composed of half devided die that combines to form circular pressing face with diameters D1, D3, respectively. The plastic worked pipe having the final diameter is properly treated for recrystallization.