Pipes and thin-wall tubes are produced of corrosive-resistant steel, nickel-based heat-resistant and heatproof alloys; their chemical composition should comply with the requirements of GOST 5632-72 standard.
Main corrosive-resistant steel grades include 08Cr13, 12Cr13, 10Cr23Ni18, 08Cr22Ni6Ti, 12Cr18Ni10Ti, etc. The most highly-demanded grades of heatproof alloys used for producing pipes are CrNi78Ti (EI435), CrNi77TiAlB (EI437B), CrNi60WTi (EI868), CrNi32Ti (EP670), 36NiCrTiAl (EI702), etc.
Production
Pipes are supplied in seamless and welded form. Seamless pipes are made y stretching cold-, warm- or hot-worked blanks. Rods serve as blanks for producing seamless pipes. Such semi-finished products are supplied both with or without thermal processing. Extremely thin-walled pipes belong to a separate class of tubular goods with walls 0.12-1.00 mm thick.
Another type includes electric-welded corrosive-resistant pipes. Sheet blanks serve as the primary material for producing them. They are bent into pipe form and welded. Such pipes are supplied after thermal processing. if required, the surface is mechanically processed (polished).
The sizes of corrosive-resistant, heatproof and heat-resistant seamless pipes and their allowable tolerances so as supply condition, mechanical properties are regulated by TC 14-3-582-77, TC 14-3-520-76, TC 14-3-571-77, those of welded ones - by GOST 11068-81 standard.
Application
Heatproof and heat-resistant pipe are applied where materials should be highly-resistant to gas corrosion and durable under high temperatures and highly corrosive-resistant in aggressive media. Their applications include aircraft engineering and power-plant industry.