Austenitic stainless steel for high vacuum and high purity gas tube application

Abstract

The object of the present invention is to provide stainless steel for high vacuum and high purity gas tube applications not having intrusion of impure particles into a processing gas and being cost-efficient. In order to accomplish the object, the present invention provides an austenitic stainless steel for a high vacuum and high purity gas tube application, the stainless steel including, in percent by weight, 0.1% or less of C, 1% or less of Si, 0.5 to 2% of Mn, 0.05% or less of P, 0.01% or less of S, 15 to 30% of Cr, 7 to 20% of Ni, 4% or less of Mo, 3% or less of Cu, 0.05% or less of N, 0.01% or less of B, 0.01% or less of O, a remaining part of Fe, and unavoidable impurities, wherein Ti content is limited to 0.005% or less, Al content is limited to 0.005 to 0.05%, and Ca content is limited to 0.0005 to 0.003%.

1 . An austenitic stainless steel for a high vacuum and high purity gas tube application, the stainless steel comprising: in percent by weight, 0.1% or less of C, 1% or less of Si, 0.5 to 2% of Mn, 0.05% or less of P, 0.01% or less of S, 15 to 30% of Cr, 7 to 20% of Ni, 4% or less of Mo, 3% or less of Cu, 0.05% or less of N, 0.01% or less of B, 0.01% or less of O, a remaining part of Fe, and unavoidable impurities, wherein Ti content is limited to 0.005% or less, Al content is limited to 0.005 to 0.05%, and Ca content is limited to 0.0005 to 0.003%. 
     
     
         2 . The austenitic stainless steel for a high vacuum and high purity gas tube application as claimed in  claim 1 , wherein the number of sliver defects having a length of 3 mm or more in a rolling direction on a surface of cold rolled coils of the austenitic stainless steel is less than five per coil of 100 m. 
     
     
         3 . The austenitic stainless steel for a high vacuum and high purity gas tube application as claimed in  claim 1 , wherein an oxide and a nitride are not detected on the surface of beads when welding the austenitic stainless steel using an Ar protective gas and a nitrogen gas.