To determine the material grade of stainless steel lockers (201/304/316), the "magnetic test + chemical solution inspection" combination is recommended first, along with visual and label verification for the highest accuracy.

I. Basic Appearance and Logo Inspection

Check the product manual or certificate of conformity. Genuine manufacturers will clearly label the material grade (e.g., "304 Stainless Steel" corresponds to 304, "06Cr19Ni10" corresponds to 316).

Upon examining the surface texture, the 304/316 stainless steel features a smooth and even surface with clear brushed patterns and no visible oxidation spots; the 201 stainless steel surface is darker and prone to rusting upon long-term exposure.

Inspection of weld joints reveals that 304/316 welding is smooth with no pores, while 201 welds are prone to blackening, cracking, or rust stains.

Section Two: Core Testing Methods (ranging from easy to difficult, with increasing accuracy)

1. Magnetic Testing (Initial Screening)

Tool: Common magnet (the stronger, the more accurate).

The evaluation logic: The higher the nickel content in stainless steel, the weaker the magnetism.

Results: Grade 201 stainless steel has strong magnetism with significant attraction; Grade 304 stainless steel has extremely weak magnetism, barely attracting or slightly attracting; Grade 316 stainless steel is almost magnetically neutral, not attracting at all.

Note: This method is only for preliminary judgment. Some processing techniques may cause the 304 material to exhibit slight magnetism, requiring the use of additional methods.

2. Stainless Steel Testing Solution (Accurate Judgment)

Tools: Specialized 304/316 test solutions (including nickel reagents) available online, affordable and easy to use.

Step-by-step Instructions: Gently sand a discreet area of the wardrobe (to remove the surface oxidation layer), then drop 1-2 drops of the solution onto the sanded area and observe the color change.

Results: Grade 201 stainless steel turns red and purple quickly, with darker colors indicating poorer quality; Grade 304 stainless steel solution shows minimal or no color change; Grade 316 stainless steel solution remains unchanged.

3. Spectrometer Analysis (Professional Verification)

Applicable scenarios: High material requirements (such as in the medical or food industry), requiring precise confirmation of ingredients.

Operation: Contact a professional testing institution or manufacturer and use a spectrometer to test the nickel, chromium, and molybdenum content of the stainless steel.

Results: 304 stainless steel contains 18%-20% chromium and 8%-12% nickel; 316 stainless steel contains 16%-18% chromium, 10%-14% nickel, and 2%-3% molybdenum; 201 stainless steel contains 16%-18% chromium and 3.5%-5.5% nickel (significantly lower than 304/316).

Avoidance Tips

Don't solely rely on "magnetic-free = 304/316" as some 201 stainless steel can also be magnetically weakened through processing.

Testing of the liquid is required on the sanded base material; surface painting and electroplating can affect the results.

Be wary of low-priced products claiming "304 material"; the price of 201 stainless steel is about half of 304, so a significantly lower quote likely indicates material fraud.