What is 18-8 Stainless Steel, The most common metal used in reusable metal bottles?
The “18-8” (or 18/8) in stainless steel is used to indicate the percentage of chromium and nickel are used in the steel respectively. This means that 18-8 stainless steel is made of 18% chromium and 8% nickel. These two compounds help the stainless steel avoid corrosion, and last much longer than regular steel.
To back up a bit, steel is a metal alloy (a metal mixture made of more than one kind of metal) made mainly of iron mixed with carbon. Stainless steel gets its unique properties by also adding other materials into the mix, the two most important being chromium and nickel.
The 18-8 stainless steel is the most commonly used stainless steel in cookware and food or beverage containers. In the case of thermal insulated bottles, 2 layers of the same steel are used to protect the bottle’s internal temperature from changing (be it getting colder or warmer). The double layer prevents a temperature change by keeping the drink away from external temperature. In this article, I explain how condensation causes the temperature of a bottle to change. The double-layer bottles use the two layers to slow the change of temperature. Any system that is locked tight will remain as it is for longer, it will take external forces, like temperature, a longer time to affect what is inside.
What Do Chromium and Nickel do in Stainless Steel?
Both chemicals work to add to the physical properties of stainless steel, which differentiate it from regular steel, like resistance to corrosion, and high temperature strength (see the full list below). Nickel is also non-magnetic, making the steel it is in either non-magnetic, or minimally magnetic. Since stainless steel is non-magnetic, it can be used in many more applications. If you try to put a magnet against your bottle, you will find that it either does not stick at all, or has a very weak pulling force towards the bottle.
What Is Special About 18/8 Stainless Steel Compared to others?
Here is a list of some of its best qualities per a lead 18/8 stainless steel manufacturer:
- Resistance to corrosion
- High temperature strength
- Prevention of product contamination
- Resistance to oxidation
- Ease of fabrication
- Excellent formability
- Beauty of appearance
- Ease of cleaning
- High strength with low weight
- Good strength and toughness at cryogenic temperatures
- Ready availability of a wide range of product forms
- Low Cost to manufacture
To break it down: it is easy to make, strong, light weight and is very cheap. The user friendliness means that the factories making the bottles do not have too much trouble making the bottle. The light material means that the bottles are travel friendly. The heavier the bottle, the more of a nuisance it becomes while traveling. The material is also strong, this is why when you drop your bottle it does not break, or completely deform. Stainless steel is known for its strength, again making it a great material for bottles. Long trips mean a bottle might fall or hit a lot of different surfaces, so its resilience means it can last the whole journey and then some. Since the bottle is easy to make, this also means it is cheaper on the end consumer (you) so you don’t have to worry so much about affording a good bottle.
What are 304, 302, 305 stainless steels?
These are all variants of the same 18-8 stainless steel described in this article. All these metals have the same percentage of chromium and nickel, but differ in the other compounds found in the steel. The most common type of 18-8 stainless steel is the 304 variant. This is why, some bottles are slightly magnetic while others are not magnetic at all. All the other alloys play a role in the characteristics of the bottle.