Stainless steel is used in many of your components, which requires excellent stainless steel machining services. However, there are many types of stainless steel, especially 304 and 316 stainless steel are the most frequently used. Many people are confused about which one to select to produce the required parts. So today, thinking about your concerns, I would like to explain in detail the differences between 304 stainless steel and 316 stainless steel.
What is 304 Stainless Steel?
304 Stainless Steel is a standard grade of stainless steel and is also austenitic stainless steel. The metal contains approximately 18% chromium and 8% nickel in its chemical composition. The purpose of chromium is to increase the quality of rust and hardness. It creates an invisible oxide layer on the surface of the metal. Nickel is added to improve the metal’s corrosion resistance and stainless steel’s silvery, polished look.
18/8 stainless steel is a popular naming method based on its chemical composition. It can be said to be an informal way of describing it. 304 stainless steel is a stainless steel grade named according to international standards. Especially in daily applications such as kitchen utensils and tableware, the performance and uses of these two are exactly the same.
Pros and Cons of 304 Stainless Steel
1. Pros of 304 Stainless Steel
(1) Rust Resistance
Most common benefits of 304 stainless steel. 304 Stainless Steel is stable and very difficult to rust, even in damp environment or mildly acidic conditions.
(2) Food Safety
304 Stainless Steel is a non-reactive metal. It does not chemically react with your food or alter the flavor of your food. So, the metal is also used to make kitchen utensils and cutlery.
(3) Good Strength
304 stainless steel is strong and durable, and its toughness is also excellent, and it can withstand large external forces.
(4) Aesthetics
304 stainless steel has a smooth surface and a strong metallic texture, and can be used in various applications that require exquisite appearance.
(5) Easy To Machining
Needless to say, in the field of CNC machining, 304 stainless steel is widely used. The material is easy to weld, cut, and shape, and can be made into parts of various complex shapes.
2. Cons of 304 Stainless Steel
(1) Poor Heat Conductivity
Yes, stainless steel is not a good conductor of heat, so as a pot, heating uneven may occur. The stainless steel pot you are currently using is essentially a composite bottom, with either layers of aluminum or copper cores bonded to the bottom of the pan.
(2) Higher Cost
304 stainless steel is more costly to produce because it contains higher levels of nickel, which is a costly ingredient. Therefore, this is costlier than the rest of metals.
(3) Scratching
304 Stainless Steel is a shiny and hard metal material, but if you toughly rub it with wire ball it will also make a little scratch.
What is 316 Stainless Steel?
316 stainless steel is also a type of austenitic stainless steel,which is very similar to 304 stainless steel. However, this metal material is superior, especially in terms of corrosion resistance. The chemical composition of 316 stainless steel consists of 18% chromium, 10% nickel and 2% molybdenum. So, the metal has a better resistance to chlorides and other normal industrial solvents and can be used in more severe chemical and marine environments.
Pros and Cons of 316 Stainless Steel
1. Pros of 316 Stainless Steel
(1) Superior Salt Resistance
The killer feature of 316 stainless steel. In contrast to 304, which rusts in saltwater environment, 316 stainless steel contains molybdenum to resist the chloride attacks. This makes it perfect for marine hardware, coastal buildings and other severe exposure.
(2) Chemical Resistance
In addition to salt resistance, 316 stainless steel has good chemical resistances such as to sulfuric acid, acetic acid, and formic acid. Therefore, the metal is often used in various extreme chemical environments.
(3) Medical Grade Hygiene
You may not know that many orthopedic implants used by patients are also made of 316 stainless steel. This is because the metal has excellent biocompatibility and has an extremely stable structure.
(4) Heat Resistance
316 stainless steel can be used in extremely high temperature environments. The metal has higher strength and oxidation resistance, better than 304 stainless steel and less prone to creep at elevated temperature.
2. Cons of 316 Stainless Steel
(1) Higher Cost
While the cost of 304 stainless steel is not cheap, the price of 316 stainless steel is still 30% to 40% higher than that of 304. This is because more nickel is added to the metal as well as expensive molybdenum.
(2) Less Machinable
Also, because 316 has a higher toughness and hardening rate, the metal is more difficult to process, making it harder to form. This is critical for manufacturers. After all, if you want to process 316 stainless steel, the tool wear will accelerate and the production efficiency will be reduced, but the cost of the product will increase.
304 Stainless Steel vs 316 Stainless Steel
Well, by reading the definitions, advantages and disadvantages of 304 and 306 stainless steel above, you must have an understanding of these two stainless steel types.
Although 304 stainless steel and 316 stainless steel are both common stainless steel materials, it is difficult to distinguish them on the physical level. You may think they are different on the chemical level. However, there are still many differences between the two in terms of performance and application. Then I will compare them in all aspects.
1. 304 vs 316 Stainless Steel Strength
The tensile strengths of 304 stainless steel and 316 stainless steel are actually roughly the same, with both being about 515-620 MPa (75-90 ksi). However, the two will start to diverge in high temperature conditions. The 316 material structure is relatively stable at high temperatures because it contains molybdenum, but 304 will creep at this extreme environment.
2. 304 vs 316 stainless steel Food Grade
Both 304 and 316 stainless steel are commonly used in food grade applications, but 316 stainless steel is considered a superior “food grade” material.
Many of the household kitchenware, food containers, etc. we use are made of these two types of stainless steel. In your daily life, cooking, cleaning pots, etc. all involve the use of salt, acid, detergents and disinfectants, many of which contain chloride. For prolonged use, 304 stainless steel is subject to pitting corrosion and crevice corrosion in a chloride environment, forming small holes on the surface, which not only influences the appearance, but also allows bacteria to grow in these holes and difficult to clean. However, 316 stainless steel has no such problem. This is because the molybdenum element present in stainless steel provides it with an advantage when used in food grade applications, as it increases the resistance to chloride induced corrosion.
As a result,, food-grade applications made of 316 stainless steel are more durable, which can significantly extend their service life and reduce maintenance and replacement costs. I believe this is also something you all really like, right?
3. 304 vs 316 stainless steel Price
In fact, when it comes to cost issues, I have already reviewed the shortcomings of both above, and I will briefly summarize them here. In fact, 316 stainless steel and 304 stainless steel are both not cheap, but 316 is more expensive. This is because 316 stainless steel has an addition of 2-3% molybdenum, which is an expensive alloy metal. The addition of this will undoubtedly raise the manufacturing cost of 316 stainless steel. Secondly, the nickel content in 316 stainless steel is higher than that in 304 stainless steel. The higher nickel content will also make 316 more costly.
4. 304 vs 316 stainless Steel Machinability
304 and 316 stainless steel are both austenitic types of stainless steel and have similar properties in terms of machining. As austenitic stainless steels in general have a poorer machinability, machining of both stainless steels can be considered as not very good. Even so, the machinability of 304 stainless steel is usually a little better than that of 316 stainless steel.
Both 304 and 316 stainless steel have a high strength and toughness, which makes the cutting force be larger during cutting. Moreover, the surface of the material will work harden quickly while machining, which makes the further cutting more difficult and the wear of the tool is accelerated. Another thing you should pay attention to is that the material is also easy to cling to the tool when cutting, making for accumulated edges, which will affect the quality of the work surface and the life of the tool.
5. 304 vs 316 Stainless Steel Hardness
The hardness difference between these two types of metals is not very large, it is just a small difference in work hardening. The rate of work hardening for 304 stainless steel is usually a little bit higher than that of 316 stainless steel. This indicates that for a given amount of cold working, 304 stainless steel can be made harder. This is because 304 stainless steel is more prone to martensitic phase transitions during cold deformation, which increases its hardness.
6. 304 vs 316 Stainless Steel Properties
Comparison of properties, in fact, has been said a lot above. Here I will show you some aspects that have not yet been compared, and the following is shown in a table to make you see it more clearly.
| Performance Metric | 304 Stainless Steel | 316 Stainless Steel |
| Acid & Alkali Corrosion Resistance | Good – Good resistance to most oxidizing acids (e.g., nitric acid). Lower resistance to reducing acids (sulfuric acid etc)
| Excellent – The presence of molybdenum greatly increases resistance to a wide range of acids (sulfuric, phosphoric, acetic acids, among others) and bases. |
| High-Temperature Strength | Good – Suitable for intermittent use up to 870°C (1600°F) and continuous use up to 925°C (1700°F). | Superior – The presence of molybdenum enhances high temperature creep resistance and oxidation resistance, resulting in better retention of mechanical properties at high temperature. |
| Low-Temperature Toughness | Excellent – Maintains good ductility and toughness at extremely low temperatures without brittle transition. | Excellent – It also has good low temperature toughness like 304. |
| Weldability | Excellent – Easily welded without preheating or post-weld heat treatment. | Excellent – Good weldability, but because of the molybdenum content, less heat input may be required to prevent hot cracking. |
| Magnetism | Non-magnetic – Non-magnetic in the annealed condition. Cold working may impart a slight magnetism. | Non-magnetic – Non-magnetic in the annealed condition. May become slightly magnetic after cold working. |
| Surface Finish | Can be polished to a high-quality finish. | Can be polished to a high-quality finish. |
| Biocompatibility | Good – Widely used in food and medical applications. | Superior – As a result of good corrosion resistance, it is more often selected for medical implants and pharmaceutical apparatus. |
7. 304 vs 316 stainless steel Application
| Application Field | 304 Stainless Steel (Standard Grade) | 316 Stainless Steel (Medical/Marine Grade) |
| Home Kitchen | Woks, kettles, sinks, forks, knives, spoons | High-end thermos inner liners, baby utensils |
| Industrial Equipment | Food processing equipment, standard storage tanks | Pharmaceutical equipment, chemical storage tanks, paper-making equipment |
| Transportation | Car exhaust pipes, body trims | Marine hardware, yacht fittings, oil tanker pipelines |
| Medical Field | Standard hospital beds, trolleys | Surgical tools, bone screws, implants (316L) |
In Conclusion
Okay, that’s all the comparison between 304 and 316 stainless steel. Both 304 and 316 stainless steel have a critical role to play in today’s industry. The difference between the two is not just a matter of numbers, but is the result of the combined effect of element composition, environmental requirements and economic considerations. In addition, no matter what stainless steel parts you need, our company DSR can manufacture them according to your requirements and drawings.
FAQ
Q1: Is 304 or 316 better for water?
A: 316 is better than 304 stainless in water applications, especially salt water or other highly corrosive aqueous environments (e.g. seawater, or water with a high levels of chlorides). The addition of molybdenum (Mo) gives 316 stainless steel superior corrosion resistance, it can resist against pitting corrosion and crevice corrosion, 304 stainless steel will possibly corrode in such environments.
Q2: Is 304 a good grade of stainless steel?
A: Yes. 304 stainless steel is indeed a very good stainless steel and is generally regarded to be the “standard” grade stainless steel.It has good corrosion resistance, toughness and processing properties.
Q3: How long does a 304 last?
A: The lifespan of 304 stainless steel depends on the environment and the use conditions. Generally, 304 stainless steel can be service for 20 years or more. But 304 stainless steel is still corroded in extreme corrosive environment like wet, high salt, strong acid or strong alkali.
Q4: Does stainless steel 304 contain lead?
A: No. 304 stainless steel consists mainly of iron, chromium, and nickel, and it also may include traces of carbon, manganese, silicon, and other elements.
Q5: Is 304 stainless steel magnetic?
A: No. 304 stainless steel is generally non-magnetic, because it is an austenitic stainless steel and the structure is not magnetic.
Q6: Is 304 stainless steel ok for outdoor use?
A: Yes. 304 stainless steel is suitable for outdoor use, particularly in the environment of daily life, and it has good corrosion resistance. But one thing you should pay attention to is that the 304 stainless steel can rust in high humidity, salt mist (such as the seaside), or in acid environment.
Q7: Is 304 stainless healthy?
A: YES. 304 stainless steel is a healthy and safe material, so it is widely used in food processing, kitchen utensils, medical equipment and other fields.
Q8: How to remove rust from 304 stainless steel?
A: There are many methods for removing rust from 304 stainless steel, such as washing with white vinegar or baking soda. To get rid of the rust, you can use white vinegar, apply it to the rust areas and let it sit for a few minutes before you wipe them off. Or you can prepare a baking soda paste by mixing it with water and apply this on the affected area before you rinse off.
Of course, you can also use a commercial stainless steel cleaner or rust remover, follow the product instructions and wipe dry with a soft cloth after the cleaning. Then, you need to apply the stainless steel protectant to prevent re-rusting. But please remember wire balls or hard wire brushes are not recommended, as they can easily scratch the surface. Additionally, after cleaning you have to rinse and dry thoroughly, especially in high humidity or salty air environment, which should be maintained regularly for the service life.
Q9: How long will 316 stainless steel last?
A: Because of the excellent corrosion resistance and high strength, 316 stainless steel can have a long service life in various environments. This stainless steel can be used for over 20 years in extreme conditions and even more than 50 years in normal conditions.
Q10: What grade is 316L stainless steel?
A: 316L stainless steel is a low carbon version of 316 stainless steel and is also an austenitic stainless steel. 316L contains less carbon (≤0.03%) than 316 stainless steel.
