PURPOSE: To manufacture a seamless stainless steel tube excellent in the outside quality of the tube by minimizing surface defects by an elongator and forming titanium film on the surface, whereon flaws do not grow in spite of reduction of material temperature.
CONSTITUTION: After the surface of a two phase stainless steel of round billet or square bloom is coated by thermal spraying method, etc., with a titanium film, the tube is manufactured by the regular Mannesmann rolling method. The titanium film diffuses in the inner part of the two phase stainless steel at a high temperature, an alloy layer of α single-phase excellent in workability is formed on the surface layer of the blank, therefore, surface defects and rolled flaws become hard to generate and propagate. Further, it is effective for this alloy layer to prevent direct contact and seizure between the iron and the tool. Secondarily, the life of the tool is improved.
SOGO YASUO
MIZOGUCHI SHIGERU
TAKAGUCHI MITSURU
Next Patent: METHOD FOR CONTROLLING ROLLING DOWN FORCE IN TEMPER ROLLING OF STEEL STRIP