Patent GB-721164-A (GB)
Title: Container of austenitic stainless steel and method of making the same
IPC: A61J1/00
Filed: 1952-02-14
Abstract: In a modification of the container claimed in the parent Specification the content of one or more of the following constituents of the alloy of which the container is formed lie within the following ranges: Cr 18-20 per cent, Ni 11-15 per cent and Mo 3-4 per cent.  The remaining constituents lie within the ranges stated in the parent Specification namely Cr 20-26 per cent, Ni 15-25 per cent, Mo 1-3 per cent and C up to 0.06 per cent.  The alloy may be subjected to a plurality of successive cold working operations to form a container with annealing in an inert atmosphere, e.g. at 2050-2150 DEG F., after each cold working. The formed container is subjected to the action at an elevated temperature of a concentrated aqueous solution of a strong inorganic acid which may also contain organic liquids.  The following solutions are referred to: 20 per cent up to concentrated hydrochloric acid; 25 per cent nitric acid; a mixture of 30 ml. of 35 per cent hydrochloric acid, 3 ml. 60-70 per cent nitric acid, 1 gram sodium chloride, 35 ml. water, 20 ml. 95 per cent sulphuric acid and 3 ml. glacial acetic acid; a mixture 30 ml. concentrated hydrochloric acid, 10 ml. concentrated nitric acid, 1 gram sodium chloride, 20 ml. concentrated sulphuric acid, 3 ml. glacial acetic acid and 30 ml. water; a mixture of 30 ml. concentrated hydrochloric acid, 3 ml. concentrated nitric acid, 1 gram sodium chloride, 20 ml. concentrated sulphuric acid, 3 ml. glacial acetic acid and 40 ml. water; a mixture of 20 ml. concentrated hydrochloric acid, 20 ml. concentrated nitric acid and 60 ml. water; a mixture consisting of 40 per cent of H2SO4, 7.24 per cent of HCI, 3.36 per cent of HNO3, 4.04 per cent of glacial acetic acid, 0.65 per cent of NaCl and 44.71 per cent of water; a mixture of 30 ml. concentrated hydrochloric acid, 3 ml. concentrated nitric acid, 20 ml. concentrated sulphuric acid and 20 ml. water; a mixture of 35 ml. hydrochloric acid, 3 ml. concentrated nitric acid, 20 ml. concentrated sulphuric acid and 50 ml. water; a mixture of 30 ml. concentrated hydrochloric acid, 3 ml. concentrated nitric acid, 20 ml. concentrated sulphuric acid, 20 ml. water and 2 ml. glacial acetic acid.  Acid compositions capable of effecting polishing of the container should contain sulphuric acid, water from 1/2 -less than 1 1/2 parts by weight of the H2SO4 present and preferably less than 60 per cent of the total composition, HCl ranging from 1/10 -\ba1/2 parts of the H2SO4, HNO3 ranging from 1/10 -\ba1/2 parts by weight of the HCl and acetic acid from 1-10 per cent by weight of the whole composition. Specification 681,098, [Group VI], is referred to.ALSO:In a modification of the container claimed in the parent Specification the content of one or more of the following constituents of the alloy of which the container is formed lie within the following ranges Cr 18.0-20.0 per cent., Ni 11.0-15.0 per cent. and Mo 3.0-4.0 per cent.  The remaining constituents lie within the ranges stated in the parent Specification, namely Cr 20.0-26.0 per cent., Ni 15.0-25.0 per cent., Mo 1.0-3.0 per cent. and C up to 0.06 per cent.  Specification 681,098 is referred to.