Stainless Steel Flat Bar Annealed and Pickled EN 1.4301/4307
Austenitic steels with designations 1.4301 and 1.4307 are the commonest stainless types and contain about 18% chromium and 9% nickel. The difference between the two grades is that in 1.4301, the maximum allowed carbon content is higher than for 1.4307 which can mean that 1.4301 has marginally higher strength. In practice, the difference in carbon between 1.4301 and 1.4307 is often of little significance. However, if welding is to be performed, 1.4307 is the preferred choice since corrosion resistance in the vicinity of the weld could be impaired for 1.4301.
Thicker flat bars of stainless steel are manufactured by hot rolling. In flat-bar format, grades 1.4301/1.4307 are standardised in EN 10088-3. Tibnor’s programme of hot-finished stainless flat bars covers the range 8-40 mm thickness with widths up to and including 150 mm.
Grades 1.4301 and 1.4307 show good resistance to corrosion in neutral water both indoors and outdoors. The steels also exhibit immunity from atmospheric corrosion. However, these stainless grades are less suitable if the environment is acidic or contains chlorides. In such instances, higher alloyed grades are needed.
The formability of hot-finished flat bars of both 1.4301 and 1.4307 is in most cold-forming operations excellent and often better than hot-rolled carbon steel. Both grades are also characterised by very good weldability and they seldom pose any problems in fabrication of welded structures. Machining, on the other hand, can pose difficulties but is facilitated via use of bespoke tooling.
Hot-finished flats in grades 1.4301/1.4307 have surface finish 1D as defined in EN 10088-3 (annealed and with surface oxide removed by pickling). Thickness and width have plus/minus tolerances as defined in EN 10058. Straightness expressed as height of arc is at most 0.004 times the bar length.