Extrusion Process with Control of Bend and Twist for Producing Shaped Tubes and Bars without Additional Processes for Cancel of Distortion and Second Forming

Research Project

Project/Area Number	14550099
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	機械工作・生産工学
Research Institution	University of Fukui
Principal Investigator	SHIRAISHI Mitunobu University of Fukui, FACULTY OF ENGINEERING, ASSOCIATE PROFESSOR, 工学部, 助教授 (30144885)
Project Period (FY)	2002 – 2003
Project Status	Completed (Fiscal Year 2003)
Budget Amount *help	¥1,300,000 (Direct Cost: ¥1,300,000) Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Keywords	Extrusion / Bend / Twist / Space frame / Turbine blade / Asymmetric cross section / Metal flow control / Inclined die
Research Abstract	The flexible extrusion process with moving dies, which has been developed by the author, is applied to forming of space frames for automobiles and turbine blades for generators. The results are summarized as follows : The flexible extrusion system, in which the die could be continuously rotated at a fixed speed during extrusion, is constructed.The extrusion tests with two-step change in the inclination angle of the die are carried out using the system.The curved products without defects in shape curved are obtained as the billets are extruded at the appropriate punch speed and rotating speed of the dies.It is confirmed that the extrusion system is effectively utilized for manufacturing elongated and complicatedly curved products. The new process, in which the billets are extruded through an aperture composed of two crossed dies inclined at a fixed angle, is proposed to supply twisted products with asymmetric cross sections such as turbine blades. The extrusion tests for rectangular and trapezoidal cross sections are carried out by use of the process. It is clarified that the bend of the extruded product decreases with increasing the standard inclination angle of the die aperture. The validity of the process is confirmed. For varying the cross section, the curvature and the angle of twist during extrusion, the new system with high flexibility is designed.The extrusion tests for symmetric and asymmetric H-type bars are executed using the system.The performance of the system is examined in detail.The H-type curved bars with various dimensions can be promptly produced without changing the dies by applying the system.