Abstract: A corrosion-resistant steel tube such as a sheath heater steel tube and boiler tube which exhibit improved resistance to dry corrosion under high temperature dry-corrosive conditions in the presence of chlorides is disclosed. The steel consists essentially of, in % by weight:______________________________________ C: not more than 0.05%, Si: 0.1-2.0%, Mn: not more than 2.0%, Cr: 18-26%, Ni: 16-30%, ______________________________________at least one of Mo: 0.5-4.0%, W: 0.01-4.00%, andV: 0.01-4.00%,N: 0-0.25%,(Ti+Nb): 0-1.5%, andthe balance iron and incidental impurities.
Type:
Grant
Filed:
March 6, 1989
Date of Patent:
August 21, 1990
Assignees:
Sumitomo Metal Industries, Ltd., Nippon Stainless Steel Co., Ltd.
Abstract: A facedown-type semiconductor pressure sensor has a Si sensing element including a diaphragm, a spacer, and a piezoresistive device embedded in the diaphragm, and a pedestal. The spacer, which is positioned between the semiconductor substrate and the pedestal, has a photolitho-graphically etched hole such that the sensing element, the hole and the pedestal define a sealed chamber. The sealed pressure chamber is substantially aligned with the diaphragm.