Stainless steel turns up in almost every trade. Plumbers pull out old sinks and tapware, fabricators end up with offcuts and turnings, kitchen fit-out crews strip out benches and exhaust hoods, and homeowners replace balustrades, pool fencing and barbecues. Once you have a pile of it, the questions are usually the same: what grade is it, and how should it be sorted before a buyer looks at it? This guide covers the basics in plain terms.
Why stainless steel is sorted separately
Stainless steel is iron alloyed with chromium and, in the common grades, nickel. Some grades also contain molybdenum. Those alloying elements, particularly nickel, are a big part of why stainless is usually handled as its own recycling stream rather than lumped in with ordinary steel.
A load that is all stainless, and ideally all one grade, is simpler to check and process than a mixed pile. If mild steel gets mixed through it, the whole lot may need re-sorting, so keep mild steel offcuts well separate from your stainless.
304 vs 316: where each typically turns up
304 is the most widely used stainless grade. You will often find it in kitchen sinks, splashbacks, benchtops, commercial kitchen equipment, food-service trolleys, appliance panels and a lot of general fabrication work.
316 contains added molybdenum, which improves its resistance to corrosion, particularly from salt and chlorides. That is why it is commonly specified for marine and coastal fittings, boat hardware, balustrades and handrails near the water, pool fencing hardware and some processing equipment.
These are typical patterns, not rules. A coastal balustrade could be 304, and a kitchen item could be 316. If you have paperwork, offcut labels or stamped markings from the original job, keep them with the material. They are often the most reliable clue you have.
The stainless steel magnet test: what it can and can’t tell you
A magnet is a handy first sort. The common 300-series grades, including 304 and 316, are austenitic stainless steels and are generally non-magnetic or only weakly magnetic. Ferritic and martensitic stainless steels, which include many 400-series grades, are attracted to a magnet, as is ordinary carbon steel.
There are some catches. Austenitic stainless that has been cold worked (bent, formed, rolled or drawn) can pull slightly on a magnet, and this is noted particularly for 304. Welds and castings may also be slightly magnetic. So a light pull at a corner, bend or weld seam does not automatically mean an item is not 300-series.
What a magnet cannot do is tell 304 from 316, because both behave the same way. Separating them reliably usually takes other methods, such as a molybdenum spot test or a handheld analyser, which a buyer may or may not use. Atlas Steels’ technical note on qualitative sorting tests for stainless steels explains the background in more detail.
In practice, if a magnet grabs firmly across the whole item, set it aside, as it is probably not 300-series stainless. If it does not pull, or only pulls slightly in worked areas, it is likely austenitic stainless and can go in your stainless pile.
Clean vs contaminated stainless
Cleaner material is easier for any buyer to assess. Before a pickup, it helps to:
- remove plastic, rubber seals, timber and insulation where you can
- unscrew or cut off mild steel brackets, bolts and fixings
- keep stainless turnings and swarf separate from solid pieces, and keep them dry and as clean of cutting oil as practical
- keep any known 316 apart from 304 or unknown grades
- store stainless away from mild steel offcuts and other metals
Items with a lot still attached, such as a sink with its tapware and waste fitted, or a trolley with plastic wheels, may be assessed differently from clean sheet or offcuts. If you are sorting aluminium at the same time, our guide to sorting scrap aluminium grades follows a similar approach.
Common scrap stainless steel items
Typical stainless scrap from homes and trade jobs includes sinks, laundry tubs, benches and splashbacks; commercial kitchen gear such as hoods, shelving and prep tables; sheet and offcuts from fabrication work; pipe and fittings; handrails, balustrade posts and wire; boat and pool hardware; and machining turnings.
Appliances such as dishwashers and fridges often have stainless panels, but they also contain plenty of other materials, so check with your buyer before assuming they will be treated as stainless. You can read more on our scrap stainless steel recycling page.
Preparing your stainless steel for a mobile pickup
Because we come to you, a little preparation makes the visit simpler. Take a few clear photos of the material, including close-ups of any stamps or markings. Give a rough estimate of the weight or volume; even “about a ute load” or “two pallets of offcuts” helps.
Mention anything mixed in, such as fixings, plastic or other metals, and whether any of it has been magnet-tested or is known to be 316. It also helps if the material is somewhere that can be reached safely. When you are ready, get in touch to arrange a pickup and share those details.
Have stainless steel scrap to sell? Oz Scrap Recycling is a mobile scrap buyer. Call 0413 609 674 to arrange a pickup in Sydney, NSW or the ACT. Payment is by bank transfer (EFT).