304 stainless steel contains 18–20% chromium, 8–10.5% nickel, and less than 2% manganese. 201 stainless steel contains 16–18% chromium, 3.5–5.5% nickel, and a high 5–7.5% manganese. Nitrogen is higher in 201 (up to 0.25%) versus 304 (up to 0.10%). High nickel in 304 enables greater corrosion resistance and stable austenitic structure. Increased manganese and nitrogen in 201 compensate strength properties but reduce corrosion resistance compared to 304.
304 vs 201 Stainless Steel
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| Grade | Cr (%) | Ni (%) | Mn (%) | N (%) | C (%) |
| 304 | 18-20 | 8-10.5 | ≤2 | ≤0.10 | ≤0.08 |
| 201 | 16-18 | 3.5-5.5 | 5-7.5 | ≤0.25 | ≤0.15 |
Impact of Alloy Elements on Material Properties
304’s elevated nickel content ensures tougher corrosion resistance, especially under acidic or chloride exposure, and superior weldability. High chromium forms a passive oxide layer, shielding 304 from oxidation. In 201, manganese and nitrogen counterbalance nickel’s reduction, lowering cost but also resulting in only moderate rust resistance, especially in moist or salty environments. 304 achieves tensile strengths around 520 MPa, yield strength near 215 MPa, and elongation to 50%. 201 has higher yield (275 MPa), tensile (up to 535 MPa), but lower elongation (~45%), causing more brittleness.
Mechanical Performance Comparison
201’s high yield and tensile strengths enable durable pressed or cold-formed parts, but limited elongation reduces deep stretch formability; cracks are likelier on complex bends. 304’s lower yield but higher ductility supports intricate forming, consistent welds, and refined surface finishing.
Corrosion Resistance and Application Suitability
Corrosion Resistance in Diverse Environments
Stainless steel 304 outperforms 201 in corrosion resistance due to its higher nickel and chromium content—8–10.5% Ni and 18–20% Cr versus 3.5–5.5% Ni and 16–18% Cr in 201. In salt spray tests, 201 developed brown rust within 24 hours, while 304 showed no significant change, even after 72 hours, confirming its suitability for food, medical, and marine environments. Stainless steel 201 resists rust in low-humidity, indoor conditions but fails rapidly in acidic, saline, or humid environments.
Typical Uses and Performance Requirements
304 dominates applications needing durability and hygiene: commercial kitchen equipment, sinks, food machinery, and medical devices (304 resists pitting and maintains polish). 201 finds use in consumer products, decorative panels, appliance housings, and interior structures where mechanical demands are moderate and exposure to corrosive elements is minimal.
Risks of Misidentification in Manufacturing and Supply Chain
Incorrect stainless steel grade selection leads to rapid product failure. Grade 304’s higher nickel and chromium content ensures superior corrosion resistance and mechanical integrity. If 201 is substituted for 304, especially in food, medical, or marine applications, rust, pitting, and structural degradation occur. Warranty claims and regulatory compliance penalties arise from substitution, affecting manufacturers and suppliers. Counterfeit and mislabeled metals are common in fast-moving supply chains, creating urgent demand for nondestructive, precise alloy verification.
Conventional Identification Methods
Manual identification relies on magnetic response and chemical spot testing. Grade 304, with greater nickel content, is less magnetic than 201. However, cold work or residual magnetism renders this method unreliable. Acid drop tests indicate chromium presence, but result interpretation is subjective and inconsistent. Both methods fail to differentiate alloy elements quantitatively or guarantee accuracy when alloy composition is close or surfaces are contaminated.
Advanced Solution: XRF Material Analyzer for Stainless Steel Authentication
How XRF Alloy Analyzer Works
X-ray fluorescence (XRF) emits primary X-rays onto a solid stainless steel sample, causing alloy elements to fluoresce at element-specific energy peaks. The analyzer captures these signals and instantly identifies the relative content of key alloy elements, including chromium, nickel, manganese, nitrogen, and iron. The full analysis requires less than 30 seconds per sample, is completely nondestructive, and does not alter the physical structure or surface of the test piece.
Features and Benefits of Lonnmeter XRF Alloy Analyzer
The device’s battery-powered, portable design ensures field and in-plant operability. Its touchscreen interface supports fast operation and customized, printable reports. Analysis is performed directly on solid articles, enabling continuous, high-throughput inspections. Lonnmeter’s detection accuracy (<±0.2% for key elements) outperforms traditional methods like magnetic screening and spot tests, which frequently misclassify grades when manganese or nitrogen levels vary.
Value Proposition for Professional Users
Batch-level verification and instant reporting cut inspection cycles by more than 60%. Digital record-keeping with unique sample tracking improves traceability for audits and supplier compliance. Consistent alloy identification prevents warranty disputes and downstream performance failures.
Request a Quote and Expert Consultation
Contact for tailored demonstration and technical evaluation of the Lonnmeter XRF Alloy Analyzer.
Frequently Asked Questions (FAQs)
How do alloy elements affect the performance of stainless steel?
Higher nickel in 304 stabilizes the microstructure, enhancing formability, ductility, and resistance to aggressive chemicals. In 201, increased manganese and nitrogen partially substitute nickel, increasing strength and hardness but lowering rust resistance. Chromium content above 18% further boosts 304’s stability against oxidation, setting it apart from 201 for demanding use.
What applications benefit most from accurate grade identification?
Construction, food equipment, medical device, and manufacturing sectors demand reliable grade verification to ensure compliance, avoid warranty claims, and guarantee end-use safety. Correct grade selection optimizes lifecycle cost, especially in environments sensitive to corrosion or sanitation.
Post time: Feb-26-2026
