In our daily life, the concept of "you get what you pay for" is deeply rooted in the hearts of the people.
Therefore, when I choose stainless steel products, I naturally think: 316 stainless steel is better than 304 stainless steel, after all, it is more expensive.
However, it wasn't until a few days ago that I met a friend who had a lot of work experience in a steel mill, and his reminder made me suddenly realize: it turns out that in the choice of stainless steel, expensive does not necessarily mean good.
That day, we talked about stainless steel in a small talk.
I mentioned that I always tend to buy 316 stainless steel products, thinking that they are of better quality. After hearing this, my friend couldn't help but smile and shook his head, pointed at me and said:
01. What is the difference between stainless steel grades?
Immediately afterward, he explained to me in detail the grades of stainless steel and the differences between the different grades.
Stainless steel, this alloy metal, is made by mixing elements such as iron, nickel, chromium, carbon, etc., in a certain proportion. Just like the different recipes in cooking, the ratio of these elements determines the performance of stainless steel.
The so-called "grades" are the names of these different formulations.
For example, we often hear about 304, 316, and even 201 occasionally encountered in the family, they are all stainless steel grades, representing different element ratios and performance.
02. What is the difference between different grades?
So, what's the difference between these different grades?
Friends told me that the main difference is their ability to withstand acids. Stainless steel, despite its name, does not mean that it will not rust in any environment.
In fact, when stainless steel encounters acidic substances, such as rainwater, acidic seasonings, etc., it is still possible to corrode. The difference in grades determines the strength of stainless steel's acid corrosion resistance.
Taking carbonated beverages as an example, if you use 201 stainless steel containers, corrosion will occur quickly, while 304 stainless steel can resist corrosion of carbonated beverages in a short time.
As for the 316 stainless steel, it remains intact even after prolonged contact with carbonated beverages. This is a significant difference in the corrosion resistance of different grades of stainless steel.
03. What is food-grade stainless steel?
When talking about "food-grade stainless steel", my friend reminded me that this is not a strict standard definition.
Although there is a national standard "Stainless Steel for Food Contact" that stipulates the corrosion resistance of food-grade stainless steel, it does not clearly specify which grade of stainless steel belongs to food-grade.
However, in practical application, it has been found that 304 stainless steel meets the requirements of this standard, so it is customarily called "food grade stainless steel".
But this does not mean that only 304 stainless steel can come into contact with food, and others such as 316 stainless steel or 430 stainless steel are also suitable for food contact.
04, Is 316 stainless steel better?
Hearing this, I couldn't help but interrupt him: "So, isn't 316 stainless steel better than 304?" Why was I told that I had been 'scammed' in the first place? ”
After hearing this, my friend smiled slightly and explained: "I just said that 316 stainless steel is stronger than 304 in acid corrosion resistance." But when choosing stainless steel, it's not just about corrosion resistance. ”
He further explained that in addition to corrosion resistance, we also need to consider the toughness, strength, wear resistance and economic cost of stainless steel.
For example, although 316 stainless steel is more resistant to corrosion, it has a relatively lower hardness and is softer.
This is also why most of our common stainless steel thermos cups are made of 304 or 201 stainless steel, and even if they are 316 stainless steel thermos cups, only the inner part of the tank is made of 316 material.
"If the thermos cup shell is made of 316 stainless steel, then it may be easily deformed or broken by a slight bump, and the surface will be relatively less wear-resistant. In this way, the service life of the thermos cup will be greatly reduced. ", explained the friend.
05. How to choose household stainless steel?
As for the question of how to choose the grade of household stainless steel products, my friend gave a clear suggestion: "304 stainless steel is the first choice!" ”
He explains that 304 stainless steel excels in both durability and safety, and is affordable and extremely cost-effective.
At the same time, he also reminded me to avoid 201 stainless steel products, because they are susceptible to corrosion from many daily necessities such as laundry detergent and shower gel.
316 stainless steel products are more suitable for specific scenarios that often need to come into contact with strong acidic foods, such as dairy products and carbonated drinks.
That's why we usually only see 316 material options on a few products such as stainless steel milk pots and drinking glasses.
Finally, to sum up:
Through this exchange with friends, I deeply realized the misunderstandings in the selection of stainless steel products. It turns out that "expensive" does not necessarily mean "good", but it is necessary to make a wise choice according to actual needs and usage scenarios.