The sheets are produced from nickel- and iron-nickel-based alloys. The most highly-demanded grades are CrNi70Ю (EI652), CrNi77TiAlB (EI437B), (EI435), (EI868), CrNi32Ti (EP670), CrNi67MoWTiAl (EP709) and Cr20Ni80. If the alloy has been produced by a special method, the grade includes corresponding letters. E.g., VI - vacuum-induction melting; VA - vacuum-arc remelting; S - electroslag remelting.
The chemical composition of the above-mentioned materials are regulated by GOST 5632-72 standard.
Production
The sheets and flat bars made of heat-resistant and heatproof alloys are produced by rolling. They can be hot- or cold-rolled. All sheets are subject to thermal processing and pickling.
During hot rolling the blanks are heated. Rolling can be made in several passes depending on the final sheet or flat bar sizes. After this several technological processes are performed for cleaning the product surfaces from by-products, attaining the required technological and mechanical properties to it and the required length and width values. Such operations include thermal processing, flattening, mechanical and chemical finishing (processing), edge trimming and cutting. Edge trimming is performed for sheets not thicker than 11 mm.
The same technological processes as for hot-rolled sheets and flat bars are performed for cold-rolled ones, but they are performed without heating the blanks.
The sheet and flat bar sizes, supply condition and mechanical properties are regulated by GOST 24982-81.
Application
Heatproof sheets and flat bars are applied in high-durable materials working under high temperatures; heat-resistant ones are used for producing corrosive-resistant materials working under high temperatures. The described conditions occur in gas turbines and furnaces. Sheets and flat bars are used for producing components of gas turbines (blades, discs, rings) and as construction materials for furnace combustion chambers.