GlossaryKind of term: Manufacturing term1.4404 (316L)
What is 1.4404 (316L)?
1.4404 (X2CrNiMo17-12-2) is an austenitic stainless steel with molybdenum and low carbon, comparable to the US grade 316L.
Its main alloying elements are chromium and nickel, with molybdenum added. Molybdenum raises resistance to chloride pitting compared with 1.4301; the low carbon content, the L in 316L, limits the risk of intergranular corrosion next to welds. It cannot be hardened by heat treatment, but it does strengthen through cold working. Typical uses include food and pharmaceutical plant, chemical process equipment, vacuum technology and marine environments.
What does the standard say about 1.4404 (316L)?
EN 10088-1 gives the composition, EN 10088-2 and EN 10088-3 the delivery conditions for flat products and for bars and sections; pressure equipment has its own product standards. The US counterpart 316L (UNS S31603) is covered by ASTM standards per product form. The composition limits largely coincide, though not entirely, and material is often dual certified. If the customer asks for an EN 10204 3.1 inspection certificate, it should name the standard and grade the drawing specifies.
How does 1.4404 (316L) behave in the shop?
1.4404 usually machines a little harder than 1.4301: cutting speeds are lower, chips break poorly and the material work-hardens as soon as the edge starts to rub. A sharp edge, a steady feed and plenty of coolant keep that in check. The price per kilo is higher than for 1.4301 because of the molybdenum and higher nickel content, and the alloy surcharge moves with those metals. If the drawing calls for pickling, passivation or electropolishing, that usually adds a subcontracted operation with its own lead time.
What is 1.4404 (316L) often confused with?
1.4404 is not 1.4401: that is also a 316 grade, but with more carbon, and so more prone to intergranular corrosion after welding thicker sections. 1.4435 has more nickel and molybdenum and is specified where corrosion or purity requirements are higher, as in pharmaceutical plant. The order should carry the grade number on the drawing, not the catch-all 316.
Frequently asked questions
What is the difference between 1.4404 and 1.4301?
1.4404 contains molybdenum and more nickel, which makes it more resistant to chlorides such as salt and some cleaning agents. It costs more per kilo and usually machines a little slower. Substituting is the customer's decision, not the shop's.
Is 316L the same as 1.4404?
In practice they are treated as equivalents, but EN and ASTM set slightly different composition limits; much material is certified to both. Quote and order to the designation on the drawing, with a certificate that states that standard.
Can 316L be hardened by heat treatment?
Not by quenching and tempering: 1.4404 is austenitic. It hardens through cold working, and low-temperature surface hardening exists as a specialist process. If the drawing asks for hardness in stainless, a martensitic or precipitation hardening grade may be needed; settle that before you quote.