Is my stainless steel threaded rod rusting? Is it a fake? Four key truths revealed!
Rusty stainless threaded rod don’t necessarily indicate “fake stainless steel,” but rather problems with the material, workmanship, or operating environment!
Stainless steel threaded bar rust Doesn’t Mean Fake: How Stainless Steel threaded rod Prevents Rust
Stainless steel threaded rod on a chromium oxide film (passivation film) on its surface to prevent rust. Once this film is damaged or environmental corrosion exceeds the material’s limits, genuine stainless steel will also rust!
For example, a 304 threaded rod at a chemical plant rusted after three months of use. Testing revealed the material was acceptable—the problem was hydrochloric acid vapor corrosion exceeding the 304′s tolerance limit.
Four Main Causes of ss all thread rod Rust (with Solutions)
| Causes of Rust | Typical Scenarios | Solutions |
| Material Downgrade | Using 201 Stainless Steel as 304 (40% Cost Difference) | Request a Material Report and Test for Nickel-Chromium Content (304: Ni > 8%, Cr > 18%) |
| Passivation Film Damage | Untreated After Welding/Scratching | Perform pickling and passivation after welding, and apply anti-rust paste to scratches |
| Chloride Ion Corrosion | Coastal Areas/Swimming Pool Equipment | Replace with 316 Stainless Steel (Molybdenum is Chloride Ion Resistant) |
| Electrochemical Corrosion | Contact with Carbon Steel + Humid Environment | Isolate Contact Surfaces (Use Nylon Washers) to Prevent Direct Contact Between Dissimilar Metals |
3-Step Guide to Quickly Identifying Fake stainless steel fully threaded rod Magnet Test (Preliminary Screening):
304/316 are slightly magnetic or non-magnetic (partially magnetic after processing). If they are strongly magnetic, they may be 430 or chrome-plated iron!
Chemical Solution Testing (On-Site):
If a stainless steel identification solution turns red in 2 minutes, it’s 201; if it doesn’t change color, it’s 304.
Spectral Analysis (Ultimate):
Spectral analysis (Ni/Cr/Mo content) instantly reveals fakes!
Note: The magnet test is not absolute! 304 may become magnetic after cold working, so other verification methods are necessary.
Saving Rusted stainless steel threaded rod – Tips for Rust Removal and Recurrence Prevention
Rusted 316 stainless steel threaded rod Treatment Process:
Mechanical Rust Removal: Use a copper brush or sandpaper to remove loose rust (do not use a steel brush! This will damage the passivation film). Chemical passivation: Soak the stainless steel in a pickling paste (such as DX520) for 10 minutes to rebuild the chromium oxide film.
Coating protection: Apply a zinc-containing stainless steel anti-rust grease (such as Mobil SHC 100) to isolate it from water and oxygen.
Contraindications:
Hydrochloric acid is strictly prohibited! It will corrode the substrate.
Do not stack with carbon steel!