Density of 1.4401 Stainless Steel (AISI 316): 7.98 g/cm3 Explained

The Density of 1.4401 Stainless Steel

The density of 1.4401 stainless steel, also designated AISI 316 and EN X5CrNiMo17-12-2, is 7.98 g/cm3, which is the same as 7980 kg/m3. This value is the standard figure used for the austenitic 316 family in mill datasheets and design handbooks, and it applies equally to the low-carbon 316L variant because the carbon difference does not change the lattice parameter enough to matter in engineering practice.

1.4401 is a molybdenum-bearing austenitic grade, with roughly 17% chromium, 12% nickel and 2% molybdenum. The face-centred cubic structure that gives the grade its toughness, ductility and chloride resistance is also what fixes its density close to 8 g/cm3, noticeably above the ferritic 430 grade and slightly above 304.

Why the Density Value Matters

Converting plate, sheet, bar or pipe dimensions into shipping and order weights.

Sizing structural members so the self-weight used in load calculations is correct.

Estimating load-bearing capacity and foundation loads for tanks and vessels.

Checking material yield and cost per tonne against the ordered tonnage.

Setting process parameters for fabrication where mass affects handling and forming.

Density of 1.4401 Compared with Related Grades

Grade	Density (g/cm3)
1.4301 / 304	7.93
1.4401 / 316	7.98
1.4404 / 316L	7.98
1.4541 / 321	7.90
1.4550 / 347	8.00
1.4845 / 310S	8.00
1.4301 ferritic 430	7.70
1.4462 / 2205 duplex	7.80

Using 7.98 g/cm3 to Calculate Weight

For flat product, the working formula is simple because the density in g/cm3, a length in metres and a thickness in millimetres combine directly into kilograms:

Plate and sheet: weight (kg) = length (m) x width (m) x thickness (mm) x 7.98.

Worked example: one 1 m x 2 m x 5 mm plate of 1.4401 weighs 1 x 2 x 5 x 7.98 = 79.8 kg.

Round bar: weight (kg/m) = diameter squared (mm) x 7.98 x 0.0007854.

Seamless or welded pipe: weight (kg/m) = 0.0251 x wall thickness (mm) x (outside diameter - wall thickness, mm).

The pipe coefficient follows from the density value: pi x 7.98 / 1000 is approximately 0.0251, whereas the familiar 0.02466 figure used for carbon steel assumes a density of 7.85 g/cm3. Using the wrong coefficient overstates or understates pipe weight by roughly 1.7%, which matters on large tonnage orders.

What Affects the Density Value

Temperature: thermal expansion lowers density gradually as service temperature rises; at 400 C the value is roughly 2% lower than at room temperature.

Composition: molybdenum and nickel additions raise density slightly, which is why 316 sits above 304 and why duplex 2205 is lighter at about 7.80 g/cm3.

Cold work: cold rolling or drawing can shift density by well under 1%, so it is normally ignored in weight calculations.

Phase balance: residual ferrite in a weld does not change the bulk density of the finished component in any practical way.

Frequently Asked Questions

Q: What is the density of 1.4401 stainless steel?
It is approximately 7.98 g/cm3, or 7980 kg/m3, and this is the figure normally quoted for 316 and 316L in European mill certificates.

Q: Is the density of 1.4401 the same as 316L?
Yes. 1.4401 and 1.4404 share the same 7.98 g/cm3 density because the only significant difference between them is the carbon limit.

Q: How do you calculate the weight of 1.4401 plate?
Multiply length in metres by width in metres by thickness in millimetres by 7.98. A 1 m x 2 m x 5 mm plate therefore weighs 79.8 kg.

Q: Why is 1.4401 heavier than 304?
The 2% molybdenum and higher nickel content increase the atomic mass per unit cell, lifting density from about 7.93 g/cm3 for 304 to 7.98 g/cm3 for 316.

Q: Does density change at high temperature?
Yes, it falls as the metal expands. For sizing at elevated temperature, apply the thermal expansion of about 16 x 10-6 per degree C over the relevant interval.

Q: What formula is used for 1.4401 pipe weight?
Weight per metre equals 0.0251 multiplied by wall thickness in millimetres multiplied by outside diameter minus wall thickness in millimetres, derived from the 7.98 g/cm3 density.