"Will drinking water from 316 stainless steel cause heavy metal poisoning for a long time?"

Under normal use, no：

Strong corrosion resistance: 316 stainless steel contains chromium, nickel, and molybdenum, and an oxide film is formed on the surface, and almost no metal is precipitated in daily use.

Comply with national standards: Regular products pass heavy metal migration tests (such as nickel and chromium), and the precipitation amount is far below the safety limit.

Material properties and safety analysis

Composition and corrosion resistance

316 stainless steel is an austenitic stainless steel, with the main components being iron, chromium (about 16-18%), nickel (10-12%), and molybdenum (2-3%). The addition of molybdenum significantly improves its corrosion resistance and high-temperature strength, especially in environments containing chloride ions (such as salt water, acidic beverages) or high temperatures, with a high temperature resistance of up to 1200-1300℃1912. Compared to 304 stainless steel (containing 18% chromium and 8% nickel), 316's corrosion resistance is more suitable for complex environments, such as medical equipment, food industry, etc.

Food-grade and medical-grade certification

Meets food-grade standards: 316 stainless steel has passed multiple international food safety certifications (such as GB 4806.9-2016), can directly contact food and beverages, and will not release harmful substances.

Medical-grade applications: Due to its biocompatibility and corrosion resistance, 316 stainless steel is often used in surgical instruments and implants, further proving its safety.

Risk of heavy metal precipitation

Under normal use conditions, the amount of metal ion precipitation of 316 stainless steel is extremely low, far below the national standard limit. But please note:

Use with caution for people with nickel allergies: 316 contains a small amount of nickel, which may cause discomfort to people with nickel allergies. Such people are advised to choose nickel-free materials (such as glass and ceramics).

Acidic or high-temperature liquids: Long-term storage of strong acidic liquids (such as lemon juice) or high-temperature boiling may accelerate metal precipitation, but the risk of daily drinking water is extremely low.

Daily use of water, tea, and coffee: Don’t worry at all. Experiments show that after 5 years of continuous use, the amount of nickel precipitated is less than 1/10 of the safety standard.

High-risk situations (not recommended):

Filling vinegar or lemon juice for more than 12 hours

Dry-burning an empty cup on fire

International certification and biosafety verification

Food contact certification: Passed the US FDA 21 CFR 175.300, EU EC 1935/2004 and other standards, allowing long-term contact with acidic (pH ≥ 5) and low-temperature liquids.

Medical grade standard: 316L (ultra-low carbon variant, C ≤ 0.03%) passed the ISO 5832-1 implant biocompatibility test and is widely used in orthopedic internal fixation devices, proving its chemical inertness in body fluid environments.

Performance comparison with common stainless steel materials

Conclusion: The corrosion resistance of 316 stainless steel (PREN ≥ 25) is 39% higher than that of 304 (PREN ≥ 19), and it has significant advantages in tap water environments containing residual chlorine (1-4 mg/L).

Derivative types and application areas of 316 stainless steel

How to identify 316 material?

1. Look at the logo

Real 316 material will be engraved with "316" or "SUS316" (bottom of the cup/instructions). Be careful if it only says "food grade" without the specific model.

2. Liquid testing

Buy "stainless steel testing liquid" online (about 10 yuan): drop it on 316: it turns light red; drop it on 304: it turns dark red; drop it on 201: it turns black.

3. Salt water test

Spray your own 5% salt water on the surface:

201 stainless steel: rust spots appear in a few hours; 304/316: still bright after 3 days

Precautions for use

1. Cleaning and maintenance

- Rinse promptly after use, wash once a week with neutral detergent

- Do not use steel wool or bleach (will scratch the anti-rust layer)

- Do not use it as a pot: Dry burning will cause deformation and damage to the anti-rust layer

- Do not store these liquids for more than 12 hours: vinegar, carbonated drinks, concentrated juice

Note for special groups: People who are allergic to metals (wearing metal jewelry will itch): It is recommended to choose a glass cup. Although 316 is safe, there is still a very low probability of causing allergies.

Why is 316 more expensive?

Element content: 316 stainless steel contains 12 nickels and 2% molybdenum, while 304 only has 8 nickels. Nickel is an important component of the cost of stainless steel, so the increase in nickel content directly leads to higher costs.

Corrosion resistance and high temperature resistance: 316 stainless steel has better corrosion resistance and high temperature resistance than 304, which makes it more widely used in industries such as medical, food, machinery and petroleum. This performance advantage makes 316 stainless steel more in demand in the high-end market, which drives up prices.

Market supply and demand relationship: The output of 316 stainless steel is relatively small and is mainly used in special industries, while 304 is the most mainstream steel grade on the market and is used in large quantities. This imbalance between supply and demand is also a reason why the price of 316 is higher than that of 304.

Ultimate selection recommendations

General household use, for room temperature water/tea: 304 stainless steel (the best value for money)

For mothers and babies/frequent acidic drinks: 316 stainless steel (safety upgrade)

For coastal cities/areas with hard water: 316 stainless steel (stronger corrosion resistance)

For limited budget and safety: 304 stainless steel + regular replacement (2-3 years)