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Chapter 3: Applications of Common Stainless Steel Alloys
EN 1.4404 / AISI 316L
The low-carbon edition of 4401, and the standard material
for most of the pharmaceutical industry world-wide.
4404 is the most common stainless steel for “critical”
parts where the common 4301 or 4306/7 just are not
good enough. 4404 is Damstahl’s best sold acid resistant
steel type and available in almost any shape and condition
including a large array of fittings.
EN 1.4418 / -
Comparatively low-alloyed, acid resistant steel, mostly
available as rods or bars. The content of only 1 % Mo and
4-6 % Ni makes the steel two-phased and mechanically
strong, and frequently, it is used for hydraulic equipment;
sometimes even plated with hard-chromium.
Very popular for Norwegian offshore use.
Due to their high elongation (> 45 %), the
austenitic steels are very ductile and perfect
for any kind of mechanical deformation, such
as deep-drawing. These flanges are made of
EN 1.4404.
EN 1.4432 / AISI 316L
Developed by the Finnish pulp and paper industry, this 2.5 % Mo steel
resembles the 4435 a lot. However, the Cr content is marginally lower,
and so is Ni. Due to the 2.5 % Mo, 4432 is slightly more corrosion
resistant than the normal 4404 without adding too much to the price.
The downside is lower availability.
EN 1.4435 / AISI 316L
The low-carbon edition of 4436 and thereby a high-alloy 4404.
Like 4432 and 4436, the extra 0.5 % Mo gives a higher corrosion resistance; however, the main
drawback is the high alloy costs due to Mo and Ni. Consequently, 4435 is the most expensive and
the most corrosion resistant standard alloy and, for economical reasons, the steel is frequently hard
to get.
EN 1.4436 / AISI 316
High-alloyed, acid resistant steel, containing 2.5-3.0 % Mo as compared to 2.0-2.5 for normal 4401
or 4404. The extra Mo improves the corrosion resistance, whereas the drawback is the higher price,
partly because of the increase in Mo and partly because of the extra Ni required to maintain the
austenite phase.
EN 1.4539 / ”904L”
Containing 20 % Cr, 25 Ni and 4.5 Mo, the 4539 is very corrosion resistant, austenitic steel. Originally
developed to handle general corrosion in strong sulfuric acid, which explains the high Ni content
and the 1.2 % Cu. “Over-austenitic” alloy possessing excellent corrosion resistance in almost any
environment, but due to the high Ni content, 4539 is very expensive. Please note that the designation
“904L” is not an AISI standard, but rather an antique Swedish factory name.
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