Tibnor can supply machined bars in the austenitic heat-resistant grade EN 1.4835. Austenitic steels in general have good high-temperature properties but 1.4835 is alloyed with, apart from chromium and nickel, silicon and cerium which confer even better creep strength and oxidation (scaling) resistance. The material can handle continuous or cyclic exposure up to 1150°C. The high content of chromium along with the additions of cerium and silicon ensure that the oxide layer remains intact and does not spall even under cyclical temperature conditions. The steel also contains small but controlled amounts of nitrogen and carbon which impart a somewhat higher room-temperature strength than for 1.4307 or 1.4404.
Rounds in 1.4835 are standardised in EN 10095. This standard covers round bars with diameters up to 160 mm. Tibnor’s programme comprises machined bars in diameters up to and including 150 mm.
1.4835 is optimised for use at high-temperatures but the resistance to aqueous corrosion at normal temperatures is still reasonable, somewhat better than 1.4301 and 1.4307. Based upon its favourable high-temperature properties, 1.4835 is used extensively in furnaces and kilns as well as exhaust systems and in plants for production of chemicals and energy.
Being austenitic, 1.4835 is easy to weld. With a correct procedure and suitable consumables, welds will exhibit the same favourable high-temperature properties as the base steel. Its cold formability is good but the somewhat higher base strength means that the forces needed will be higher than for the same dimension in steels like 1.4307 or 1.4404. Austenitic stainless grades such as 1.4835 are generally troublesome to machine but working is facilitated through bespoke tooling.
The surface finish of machined 1.4835 as stocked is 2B as defined in EN 10095. Machining, usually peeling, is carried after hot-rolled bars have been annealed; machining marks are evened out by the burnishing action of subsequent straightening. This procedure eliminates any remaining surface defects. The diameter tolerance of machined bars is k12 as stipulated in ISO 286 - 2 which is a zero-plus tolerance. In other words, the actual diameter is marginally larger than the nominal one. In addition, machined bars of stainless steel are rather straight with height of arc less than 0.001 x length.