Irin alagbara, irin jẹ ẹgbẹ kan ti ferrous alloys ti o ni awọn kan kere ti to 11% chromium, a tiwqn ti o idilọwọ awọn irin lati ipata ati ki o tun pese ooru-sooro-ini.Awọn oriṣiriṣi irin alagbara irin pẹlu awọn eroja erogba (lati 0.03% si tobi ju 1.00%), nitrogen, aluminiomu, silikoni, sulfur, titanium, nickel, Ejò, selenium, niobium, ati molybdenum.Awọn oriṣi pato ti irin alagbara, irin nigbagbogbo jẹ apẹrẹ nipasẹ nọmba oni-nọmba mẹta AISI wọn, fun apẹẹrẹ, 304 alagbara.