Stainless Steel Round Bar Machined EN 1.4462
1.4462 (Outokumpu 2205) is a so-called duplex stainless steel and as such is characterised by a roughly 50-50 mixture of austenite and ferrite. The content of chromium is higher and that of nickel is lower than for traditional austenitic stainless types such as EN 1.4404, 1.4307 or 1.4432. In common with 1.4404 and 1.4432, the steel is alloyed with molybdenum, but contains in addition also nitrogen. The yield strength of 1.4462 is about double that of the austenitic steels mentioned.
Rounds in 1.4462 are standardised in EN 10088-3. This standard covers cold-finished round bars with diameters up to and including 160 mm. Tibnor’s programme is broader and encompasses machined bars up to 180 mm in diameter.
Thanks to the high content of chromium in combination with molybdenum and nitrogen, 1.4462 is characterised by excellent corrosion resistance even in aggressive environments, especially those with high chloride content (sea water). It resists corrosion somewhat better than the similar grade 1.4460. In addition, the duplex character renders the steel much less prone to stress-corrosion cracking in chloride-laden environments than austenitic grades. These excellent anti-corrosion characteristics along with high strength makes the material an attractive alternative for load-bearing components, with machine parts for chemical plant and in the marine and offshore segments meriting special mention.
Machined bars in 1.4462 are quite easy to cold form but cold formability is not as good as for austenitic grades. In the event that such is needed, weldability is good but careful consideration must be given to selection of consumables. Duplex stainless steels are somewhat easier to machine than austenitic types but working is always facilitated through bespoke tooling.
The surface finish of machined 1.4462 as stocked is 2B as defined in EN 10088-3. 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.