Kabushiki Kaisha Kobe Seiko Sho

Haruo Tomari

Kazuo Fujiwara

Takenori Nakayama

Koji Wada

Nobuhiro Sato

Osamu Aritomi

Ikuro Hashimaoto

A process for surface treatment which comprises mechanically polishing the surface of a stainless steel component with abrasive grains having particle diameters of 1-10 .mu.m to such an extent that the surface has a work-strained layer formed therein which is characterized by that X-ray diffraction by the (111) plane of austenitic iron gives the diffraction beams whose half-value width (2.theta.) is greater than 0.5 degree, and subsequently performing heat treatment in an atmosphere in which the partial pressure of oxygen is low, thereby forming an oxide film composed mainly of chromium oxide which has a thickness greater than 200 .ANG. and a surface roughness R.sub.max smaller than 1 .mu.m. The surface-treated stainless steel exhibits outstanding corrosion resistance to halogen gases such as Cl.sub.2, HCl, and F.sub.2. It has such a smooth surface that it hardly adsorbs moisture vapor and gases. Therefore, it is suitable for use as components of semiconductor manufacturing apparatus.

Surface treatment of stainless steel component for semiconductor

A nitrogen-containing dual phase stainless steel with high hot workability, containing in percentage by weight:

Nitrogen-containing dual phase stainless steel with improved hot

Disclosed herein is a dual phase stainless steel suitable for use in sour wells. It comprises 0.06-0.20% C, .ltoreq.1.0% Si, 2.5-4% Mn, 20-27% Cr, 5-8% Ni, 2.5-4% Mo, 0.3-2% Cu, 0.1-0.25% N, 40-60% ferrite and the balance Fe and inevitable impurities. It may further contain one or more metals selected from Ti, Nb and V in a total amount of 0.1% to 0.5%. The dual phase stainless steel is excellent in proof strength, tensile strength and elongation and is capable of exhibiting good corrosion resistance in Cl.sup.- --CO.sub.2 --H.sub.2 S environments.

Growing community of inventors

Hyogo, Japan

Haruo Tomari