General metal buyer FAQs and grade comparisons — stainless steel, aluminum, copper, and other non-electrical-steel materials.
Yes, stainless steel can rust. It resists rust because a thin chromium oxide film seals its surface. Chlorides, trapped dirt, iron contamination, welding heat or the wrong grade can break that film, and then the steel underneath corrodes like any other iron alloy. By the ZHX Steel technical team. Published 9 October 2026. Last updated
Pure aluminum melts at 660.3°C (1220.6°F, 933.5 K). Commercial alloys don’t have a single melting point. They melt over a range that starts anywhere from about 475°C to 645°C and finishes by roughly 595°C to 657°C, depending on the alloy. The popular 6061, for example, starts to melt at about 582°C and is fully liquid
The density of aluminum is 2.70 g/cm³, which is 2,700 kg/m³, 0.0975 lb/in³, or about 168.5 lb/ft³. That’s for pure aluminum at room temperature. Common alloys stay close to it: most fall between 2.64 and 2.81 g/cm³, depending on how much magnesium, copper, or zinc they carry. The comparison most people care about: aluminum weighs
Is aluminum magnetic? Not in the way most people mean. A fridge magnet won’t stick to an aluminum can, window frame, or sheet, and no amount of bending, machining, or cold work changes that. Technically, aluminum is paramagnetic: a very strong magnetic field pulls on it slightly, but the effect is so small you need
No, aluminum does not rust. Rust is iron oxide, and aluminum contains no iron, so the reddish-brown flaking you see on old steel cannot form on it. What aluminum does instead is oxidize instantly into a thin, hard layer of aluminum oxide that seals the metal underneath. That layer is why an aluminum ladder looks
The short answer: it depends on the grade, and sometimes on how that specific piece of metal was formed. Austenitic grades — 304, 316, 316L, the ones you’ll find on most kitchen equipment, food processing gear, and marine hardware — are essentially non-magnetic in their normal annealed state. Ferritic grades (430, 409) and martensitic grades
The short answer: 316 adds 2-3% molybdenum that 304 doesn’t have, which buys real pitting and crevice resistance in chloride environments — salt water, de-icing salt, chlorinated cleaning agents — for roughly 25-90%+ more money depending on the market and the month. For most indoor, freshwater, or general food-contact use, 304 is the right call.
