REMOTE VISUAL EXAMINATION OF STAINLESS PIPELINES FOR PHARMACEUTICAL INDUSTRY
For the construction and maintenance of stainless pipelines the remote visual examination is employed. The weld roots and the pipe-wall inside are inspected to detect possible defects that could result in corrosion and bio-chemical processes. Such defects are mechanical and thermal damages to the oxide layer and defects in the weld roots. The remote visual examination is mandatory with welding and mounting of pipework systems. It is also used in regular inspections of the inner surfaces and welds during pipe operation in order to detect locations of potential corrosion and nests of micro-organisms. The welded pipelines made of stainless steel should fulfil relevant general and sanitary requirements. There should be neither undercuts nor unevenness at the root side since colonies of micro-organisms may occur at such areas. The oxide layer protecting a metal against corrosion should not become dark-coloured close to the weld due to a thermal influence. The paper treats sanitary requirements concerning stainless pipelines used in pharmaceutical factories. Weak points at the weld root side are shown. The relationship between colouring of the over-heated area and corrosion resistance of the welded joint is indicated. The importance of the remote visual examination and the assurance of weld quality in the production of equipment for the pharmaceutical and food-processing industries is underlined).
Welding of stainless steels corrosion in welds: effect of oxides, slag and weld defects on the pitting resistance
Points out that the pitting resistance of welds in stainless steels is often inferior to the parent metals, and is an important factor to consider during the selection of materials of service in corrosive environments. Notes that an empirical pitting resistance equivalent (PRE), often expressed as PRE = % Cr + 3.3 × % Mo + 16 × % N, is used to rank different parent metals and that during welding, a number of metallurgical‐and surface‐related reactions take place locally, which make it impossible to predict the pitting corrosion resistance by a single expression. Reviews the effects of oxides, slag and other weld defects on the pitting resistance of welds in stainless steels, and highlights the importance of including the properties of fabricated areas into the life cycle cost (LCC) analyses.
NEW DECAPODS FROM THE NAVIDAD FORMATION (MIOCENE) OF CHILE
Abstract A new Miocene decapod fauna is described from the Navidad Formation of coastal Chile. The fauna includes five callianassoid taxa, none of which is preserved sufficiently to identify to species level. New species include Calappilia? chilensis, Hepatus spinimarginatus, Proterocarcinus navidad, Pilumnus cucaoensis, and Pinnixa navidadensis. A possible rhizopine member of the Pilumnidae Samouelle, 1819, is described. Trichopeltarion levis Casadío et al., 2004, previously known from the late Oligocene of western Argentina, was also recovered from these rocks. Calappa circularis Beurlen, from the lower Miocene Pirabas Formation in Brazil, is herein referred to Calappilia. This report greatly increases the known number of fossil decapods from Chile and sets the stage for paleobiogeographic comparison of the decapod faunas of Chile and Argentina.