Stainless steel: myths, facts and what buyers should check
Most claims we see go wrong not because the steel was bad, but because something was assumed and never written down. Here are the 16 beliefs we hear most often in our years in the trade since 1989, and what to do instead.
Grade and materialForming, welding and finishQuality and paperworkPrice and trade
Grade and material
Myth“Stainless steel never rusts.”
Fact. It resists rust; it is not rust-proof. A thin chromium-oxide film protects the surface, and that film can break down. Salt and sea air, bleach and cleaning acids, iron particles from carbon-steel tools, and coils stored wet or in contact with mild steel can all leave rust spots. Low-nickel grades such as 201 and the J-series, and ferritic 430, show stains sooner than 304 in wet or coastal use.
What to do: Match the grade to where the product will live. Keep coils dry and wrapped, store them away from mild steel, and use protected slings and clean tools.
Myth“If a magnet sticks, it is not real stainless — or not 304.”
Fact. A magnet tells you the family, not the grade. 430 and 409 are ferritic stainless steels and are magnetic by nature. 304 is non-magnetic when annealed but turns partly magnetic after deep drawing or heavy cold work. 201 is non-magnetic too, yet carries far less nickel than 304.
What to do: Check chemistry, not magnetism. A spectro or handheld PMI test takes a minute and shows the real nickel, chromium and manganese.
Myth“More nickel is always better.”
Fact. Nickel buys corrosion resistance and formability, and its price moves with LME nickel every day. 430 is the usual choice for induction-base utensils because it is magnetic. 201 and J4 suit dry-use, price-led products. 304 earns its premium in food contact, wet and outdoor use.
What to do: Specify the grade by end use, not by habit. Paying for nickel the product does not need is money left on the table.
Myth“304 is 304 — every mill's is the same.”
Fact. Standards give ranges, not a single recipe. Under ASTM A240, 304 allows nickel from 8.0 to 10.5% and chromium around 18%, and some sellers sit at the very bottom of the range or below it. Mills also differ in cleanliness, flatness, surface and how tightly they hold thickness.
What to do: Write minimum nickel and chromium into the contract, name the standard (ASTM A240, JIS G4305 or IS 6911), and ask for test results from your own lot, not a sample sheet.
Myth“201 and J-series are fake stainless.”
Fact. They are recognised low-nickel austenitic grades. 201 is listed in ASTM A240, and low-nickel grades for utensils are covered in India by IS 15997. Part of the nickel is replaced by manganese and nitrogen. They do well in dry, indoor, price-led products. The trouble starts only when they are sold, or bought, as 304.
What to do: Buy them for what they are and price them as what they are. A quick chemistry test settles which grade is in your hands.
Myth“‘Food grade’ is a grade.”
Fact. There is no grade called food grade. 304 and 316 are the usual choices for food contact, 430 is widely used for cookware and induction bases, and low-nickel grades are used for utensils in India. What decides suitability is what touches the steel — acids, salt, heat and the cleaning it will face.
What to do: Tell your supplier the food and the process, not just “food grade”, and follow the standard your finished product is sold under.
Myth“Hardness tells you how a coil will draw.”
Fact. HRB only measures how hard the surface resists a dent. How a coil behaves in a deep-draw die depends mainly on elongation (how far it stretches before it tears), grain size (fine, even grain flows smoothly; coarse grain gives orange peel and cracks) and how evenly it thins. Two coils at the same HRB can behave very differently: a 304 coil at 85 HRB with 55% elongation will usually out-draw one at 80 HRB with 42%. 304 also hardens quickly as it is drawn, which is why multi-stage draws often need annealing in between.
What to do: Specify minimum elongation and grain size together with the maximum HRB, and judge a disputed coil by its elongation first. A claim built on hardness alone rarely holds up.
Myth“Welding does not change stainless steel.”
Fact. Heat changes it. In standard 304, the zone heated to roughly 450–850 °C can form chromium carbides along the grain boundaries, leaving the steel next to the weld open to corrosion. The rainbow heat tint around a weld also rusts if it is left on.
What to do: For welded pipes and tubes, use low-carbon grades such as 304L where corrosion matters, control the heat input, and pickle or passivate the weld area.
Myth“A polished surface means better steel.”
Fact. Polishing changes the look and makes cleaning easier; it does not change the chemistry. It can hide scratches, pits and rolling defects for a while, and wheels or belts used earlier on mild steel leave iron particles that turn into rust spots.
What to do: Inspect the coil before it is polished, and keep separate abrasives and tools for stainless.
Myth“BA and 2B are just bright and dull versions of the same thing.”
Fact. 2B is cold rolled, annealed, pickled and lightly skin-passed, giving a smooth, matte-grey surface. BA (bright annealed) is annealed in a controlled atmosphere and is not pickled, giving a near-mirror surface. BA costs more and scratches show easily.
What to do: Choose the finish by what happens next. If the part will be ground or polished anyway, BA may be money wasted. If you need BA, ask for PVC film or paper interleaving.
Quality and paperwork
Myth“The label and the mill test certificate settle the quality question.”
Fact. A coil label, a printed PVC film and an MTC are all the mill's own statements. Certificates get copied, re-used or matched to the wrong coil, and printing a grade on film costs nothing.
What to do: Match the coil number on the label to the MTC, spot-test chemistry on arrival, and use third-party inspection before loading for large or new-mill orders.
Myth“Import paperwork is the supplier's problem.”
Fact. In India, stainless flat products come under BIS Quality Control Orders (IS 6911 for plate, sheet and strip). Exemptions have come and gone over the years. A mill without a valid BIS licence for the grade can leave your container stuck at the port, and the buyer carries that cost.
What to do: Before booking, confirm the mill's BIS licence covers your grade and the current rule for your product. We check this on every order.
Price and trade
Myth“The lowest price per ton is the cheapest deal.”
Fact. You pay by weight but sell by piece. Thickness on the minus side of tolerance gives more sheets or circles per ton; on the plus side, fewer. Edge condition, coil weight, surface defects and circle recovery all change the real cost.
What to do: Compare cost per usable piece, not price per ton. Our Circle Cost Calculator works this out for circles.
Myth“A ton is a ton, whatever the grade.”
Fact. Grades differ in density. 304 weighs about 7.93 g/cm³ and 430 about 7.70, so at the same thickness a ton of 430 gives roughly 3% more sheet area than a ton of 304. Theoretical weight (from size) and actual weighed weight also differ with thickness tolerance.
What to do: Compare offers by area or pieces per ton, and agree in the contract whether you pay on actual or theoretical weight.
Myth“When nickel falls, coil prices fall the same day.”
Fact. Mill prices follow nickel with a lag, and nickel is only part of the story. Ferrochrome, scrap, mill stocks, Chinese demand, freight and the USD/INR rate all move the landed price. 430 barely reacts to nickel at all.
What to do: Watch the trend over a couple of weeks, not one day's LME close. Our broadcast list sends these moves as they happen.
Myth“The CFR price is the landed price.”
Fact. CFR covers the steel and the sea freight. After that come customs duty, IGST (recoverable as input credit if you are registered), any anti-dumping or safeguard duty on that origin, port and CHA charges, inland freight, LC and bank charges, insurance — and the exchange rate between booking and payment.
What to do: Work out the landed cost per kg before comparing an import offer with a domestic one.
Before you book: a checklist
Put each of these in writing — in the inquiry, the offer and the contract. If it is not written, it was not agreed.
| Grade and chemistry | minimum Ni, Cr, Mn; the standard it follows |
| Size and tolerance | thickness, width and their plus/minus limits |
| Finish and protection | 2B, BA or No.4; PVC film or paper interleaving |
| Edge and coil | mill or slit edge; coil ID, maximum coil weight |
| Mechanical properties | hardness and, for deep drawing, elongation and grain size |
| Proof of quality | MTC per coil, third-party inspection, test on arrival |
| Compliance | valid BIS licence for India; correct HS code on documents |
| Packing and shipping | seaworthy packing, eye-to-sky or eye-to-wall, port and Incoterm |
| Money terms | LC or TT terms, tolerance on quantity, what happens on a claim |
Not sure what to specify for your product? Tell us what you make and we will suggest the grade, size and finish.
Send an inquiryThis guide is general information from our trading experience, not a technical or legal specification. Standards and import rules change; confirm the current position before you contract. Want updates when they do? Join our broadcast list.
