What does 304 mean on the water cup? Which one is better for drinking water, 304 or 316 stainless steel?

When we buy thermos cups and stainless steel tableware, we will see numbers such as 304 and 316. These numbers actually represent the material of the inner liner. The most common one is 304 stainless steel, which is suitable for food and medical equipment.

What does 304 on the water cup mean?

This is the material model of the inner liner of the water cup, which refers to 304 stainless steel, the full name of which is austenitic stainless steel. 304 stainless steel is a nationally recognized food-grade stainless steel, which is generally more common in stainless steel tableware. 304 stainless steel is a grade of stainless steel produced in accordance with the American ASTM standard. 304 stainless steel is widely used in tableware, water cups and other daily necessities due to its good corrosion resistance and heat resistance.

In order to maintain the inherent corrosion resistance of stainless steel, the steel must contain more than 18% chromium and more than 8% nickel. So most cups are marked as 304, but there are also illegal merchants who deceive consumers.

Which one is better for drinking water, 304 or 316 stainless steel?

316 stainless steel is better! Both 304 and 316 are austenitic stainless steels, both with a content of about 16-18%. The difference is that 316 stainless steel has 2% more Mo, so the corrosion resistance of 316 stainless steel, especially the tolerance to chlorine corrosion, is better than 304.

In addition, 304 stainless steel contains an average of 9% nickel, while 316 stainless steel contains an average of 12% nickel. Nickel can improve high-temperature durability, mechanical properties, and oxidation resistance in metal materials. Therefore, the content of nickel in the material directly affects the comprehensive performance of the material.

Why must 304 stainless steel be used for food

304 stainless steel is a very common stainless steel with a density of 7.93g/cm3, also known as 18/8 stainless steel. Its metal products are resistant to high temperatures and have good processing properties, and are widely used in industrial and furniture decoration industries as well as food and medical industries.

The most important elements in 304 are nickel and chromium, but not limited to these two elements. The specific requirements are determined by the product standard. The common judgment in the industry is that as long as the nickel content is greater than 8% and the chromium content is greater than 18%, it can be considered 304 stainless steel.

304 stainless steel is the most widely used chromium-nickel stainless steel. It is a widely used steel with good corrosion resistance, heat resistance, low temperature strength and mechanical properties, hot processing properties such as stamping and bending, and no heat treatment hardening phenomenon (using temperature -196℃～800℃). It is corrosion-resistant in the atmosphere. If it is an industrial atmosphere or a severely polluted area, it needs to be cleaned in time to avoid corrosion.

Suitable for food processing, storage and transportation. Has good processing performance and weldability. 304 stainless steel is a food grade stainless steel approved by the state.