To provide a large spiral screw consisting of a stainless steel having excellent corrosion resistance with a diameter ratio exceeding 3.5 at low cost.
A stainless steel-made strip in which burrs, fracture cross sections, and work-hardened layers introduced by the shearing are removed by cutting or grinding a sheared end face of the stainless steel-made strip shear-cut to the predetermined width is spirally wound around a core. Burrs and fracture cross sections which may cause the stress concentration are eliminated by removing the burrs, fracture cross sections, and work-hardened layers of the sheared end face; the total elongation is ensured, and generation of cracks to be easily generated in an outside diameter side end and wrinkles to be easily generated on the inside diameter side can be prevented thereby.
NAKAMURA TAKAFUMI
MORIKAWA SHIGERU
SAKAIDA SATORU
KOKUYO ALUMINUM SEISAKUSHO KK
| JPH0655223A | 1994-03-01 | |||
| JPS51117158A | 1976-10-15 | |||
| JPH06254642A | 1994-09-13 |