{"id":29240,"date":"2026-09-28T18:30:28","date_gmt":"2026-09-28T10:30:28","guid":{"rendered":"https:\/\/wanzhisteels.com\/?p=29240"},"modified":"2026-09-29T09:56:36","modified_gmt":"2026-09-29T01:56:36","slug":"316-vs-304-stainless-steel","status":"publish","type":"post","link":"https:\/\/wanzhisteels.com\/ar\/316-vs-304-stainless-steel\/","title":{"rendered":"316 vs 304 stainless steel: complete comparison guide"},"content":{"rendered":"

When buyers line up 316 vs 304 stainless steel, the question is almost always the same: do I really need the pricier 316, or will 304 do the job for less? Both are austenitic 18\/8 grades, both look alike on the rack, and both weld and polish well. The one element that separates them is molybdenum. 316 carries 2 to 3 percent of it, 304 does not. That single addition is what lets 316 shrug off chloride and salt while 304 pits and rusts in the same spot. This guide puts the two grades side by side on chemistry, corrosion, cost, weldability and use, so you can specify the right one and not pay for molybdenum you do not need.<\/p>\n\n\n\n

If you are weighing the grades for a tank or vessel, our 304 vs 316 brewery tank write up<\/a> on the equipment side works through the choice in plain terms, and our surface finish guide<\/a> covers the shared finishes.<\/p>\n\n\n\n

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\"316
304 stainless steel samples<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"untreated
SS316 untreated sample<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n

What 304 and 316 stainless steel are<\/h2><\/div>\n\n\n\n

304 is the workhorse grade. It is an austenitic stainless with about 18 percent chromium and 8 percent nickel, which is why people call it 18\/8. The chromium builds a thin passive film that keeps ordinary rust away, and the nickel gives it toughness and a clean look. Most of the stainless you see in kitchens, handrails and food plants is 304.<\/p>\n\n\n\n

316 is the same base with molybdenum added. The typical analysis runs 16 to 18 percent chromium, 10 to 14 percent nickel and 2 to 3 percent molybdenum. The molybdenum is a chloride blocker: it strengthens the passive film so the metal resists pitting and crevice attack in salt water, coastal air and many process acids. The chemistry families are set by ASTM A240 and the generic grade data is documented on Wikipedia’s stainless steel page<\/a>, which is a fair place to check the basics.<\/p>\n\n\n\n

Both grades are non magnetic in the annealed state. Cold work from cutting, bending or rolling can bring up a little attraction at the edges, but that does not mean the part is the wrong grade.<\/p>\n\n\n\n

Chemical composition: the molybdenum gap<\/h2><\/div>\n\n\n\n

This is the table that settles most arguments. The numbers are weight percent from ASTM A240, with iron making up the balance.<\/p>\n\n\n\n

Element<\/th>304<\/th>304L<\/th>316<\/th>316L<\/th><\/tr><\/thead>
Chromium<\/td>18.0 – 20.0<\/td>18.0 – 20.0<\/td>16.0 – 18.0<\/td>16.0 – 18.0<\/td><\/tr>
Nickel<\/td>8.0 – 10.5<\/td>8.0 – 12.0<\/td>10.0 – 14.0<\/td>10.0 – 14.0<\/td><\/tr>
Molybdenum<\/td>none<\/td>none<\/td>2.0 – 3.0<\/td>2.0 – 3.0<\/td><\/tr>
Carbon<\/td>0.08 max<\/td>0.030 max<\/td>0.08 max<\/td>0.030 max<\/td><\/tr>
Manganese<\/td>2.0 max<\/td>2.0 max<\/td>2.0 max<\/td>2.0 max<\/td><\/tr>
Silicon<\/td>0.75 max<\/td>0.75 max<\/td>0.75 max<\/td>0.75 max<\/td><\/tr>
Phosphorus<\/td>0.045 max<\/td>0.045 max<\/td>0.045 max<\/td>0.045 max<\/td><\/tr>
Sulfur<\/td>0.030 max<\/td>0.030 max<\/td>0.030 max<\/td>0.030 max<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The two gaps that matter are molybdenum and carbon. Molybdenum is what lifts 316 above 304 in corrosion. Carbon is what the L grades control: standard 304 and 316 allow up to 0.08 percent, while 304L and 316L cap it at 0.030. The low carbon version was made for welding, which we get into below.<\/p>\n\n\n\n

Corrosion resistance: why 316 wins near salt<\/h2><\/div>\n\n\n\n

The measure buyers use for pitting resistance is PREN, the pitting resistance equivalent number. The common formula is PREN = percent Cr + 3.3 x percent Mo + 16 x percent N. Nitrogen stays low in these grades, so the molybdenum term does the heavy lifting.<\/p>\n\n\n\n

\u062f\u0631\u062c\u0629<\/th>Approx. PREN<\/th>Chloride behavior<\/th><\/tr><\/thead>
304 \/ 304L<\/td>18 – 20<\/td>Pits in salt spray and pool water<\/td><\/tr>
316 \/ 316L<\/td>24 – 26<\/td>Resists splash, coastal air and seawater mist<\/td><\/tr>
2205 duplex<\/td>33 – 35<\/td>Stands up to heavy chloride and acid<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

304 is fine in dry indoor air, fresh water and mild food contact. The moment you add salt, seawater, de-icing road spray or bleach, 304 starts to pit, and the pits spread. 316 holds up in those same spots because the molybdenum closes the weak points in the film. The gap is why 316 is the rule for marine, coastal and chemical work and the reason our marine grade stainless steel<\/span><\/a> line exists.<\/p>\n\n\n\n

For the harshest chloride or acid duty, duplex 2205<\/a> scores higher still. But for the great majority of salt exposed jobs, 316 is the right step up from 304 without going to a duplex price.<\/p>\n\n\n\n

Cost: what you pay for the molybdenum<\/h2><\/div>\n\n\n\n

316 costs more than 304, and the gap tracks the nickel and molybdenum content. On the flat-rolled market, 316 typically runs about 30 to 50 percent above the same form of 304, with the spread moving as alloy prices move. You pay for the nickel first and the molybdenum second.<\/p>\n\n\n\n

The way to keep cost down is to specify 316 only where the environment needs it. Indoor structure, interior trim, fresh water lines and most kitchen gear do well on 304. Coastal, marine, chemical and poolside parts are where 316 earns the premium. If a job is inland and dry, 304 is the sensible buy and 316 is money spent on resistance you will not use.<\/p>\n\n\n\n

We stock both grades, so you can mix 304 and 316 in one order and keep the paperwork in one file. For the thin form, see our 304 stainless steel sheet<\/a> \u0648 316 stainless steel sheet<\/a>; for the thick form, our 304 stainless steel plate<\/a> \u0648 316 stainless steel plate<\/a>.<\/p>\n\n\n\n

Weldability and the low carbon L grades<\/h2><\/div>\n\n\n\n

Both 304 and 316 weld cleanly with the common methods: TIG, MIG and stick all work. The catch is sensitization. When you weld a thick section, carbon at the heat affected zone can pull chromium out of the mix and leave the seam open to corrosion along the weld line.<\/p>\n\n\n\n

That is what the L grades fix. 304L and 316L cap carbon at 0.030 percent, which keeps the chromium in the film through the heat of welding. For heavy plate, tanks, pipe and anything that gets welded a lot, 316L is the safe call. The price gap over 316 is small and the weld safety is not.<\/p>\n\n\n\n

A note for fabricators: if you weld 316 of any kind near salt, use a 316L filler and keep the seam clean. A dirty weld on a marine part will pit at the contamination, not at the grade. We cut and bevel both grades and can supply the matching filler on request.<\/p>\n\n\n\n

Strength and heat resistance<\/h2><\/div>\n\n\n\n

At room temperature the two grades have close mechanical values. Annealed 304 and 316 both reach about 515 MPa tensile and 205 MPa yield (316L a touch lower at 485 MPa), with 40 percent elongation. Neither is a high strength steel; both are chosen for corrosion and formability, not for load at the limit.<\/p>\n\n\n\n

Where they split is heat. 316 holds its strength and scale resistance better than 304 at elevated temperature, which is why it sees duty in heat exchangers, exhaust and process lines that run warm. For sustained very high heat, stabilized grades like 321 or 347 take over. Strength and hardness also rise with cold work, so a rolled or drawn part will test harder than the annealed minimum.<\/p>\n\n\n\n

Surface finishes both grades share<\/h2><\/div>\n\n\n\n

304 and 316 take the same finishes, because finish is about rolling and polishing, not about the alloy. The common ones:<\/p>\n\n\n\n