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Views: 18 Author: Shirley Publish Time: 2025-06-30 Origin: Site
What is stainless steel 304 or 316? What is the difference between them and what does each have to offer? The ASTM 304 and 316 each have advantages and disadvantages. Before choosing a company for a metal project, it is important to understand your options.
This article introduces the difference of physical properties, chemical properties, mechanical properties and application fields of 304 and 316 stainless steel, helping you understand the basic knowledge of Typical Stainless Steel.
304 stainless steel is an alloy of chromium and nickel and is the most versatile of all stainless steels. It has excellent corrosion resistance to many environments, including coastal atmospheres, industrial atmospheres, and a wide range of pH values. 304 has incredible high temperature strength and maintains its toughness at high temperatures.
316 stainless steel is a higher chromium alloy that is nearly twice as corrosion resistant as 304 and is also known for meeting ASTM A53 and other industry requirements. It is cheaper than 304 and offers great corrosion resistance, strength, and toughness in most applications.
304 and 316 are both austenitic stainless steels, but they have different compositions. 304 is an austenitic alloy with a chromium/nickel mix of about 10/90. This means that more nickel has been added to this alloy, and it is also a slightly harder, less elastic steel. The chemical composition of 304 and 316 stainless steel mainly includes:
Alloy/Composition | 304 Steel | 316 Steel |
Fe | 66% | 65% |
Cr | 18% | 16-18% |
Ni | 8% | 10-14% |
Mn | 2% | 2-3% |
Si | 1% | ＜2% |
S & P | ≤0.03% | ＜0.03% |
Each alloy has different physical properties. 304 is a soft, low-carbon steel that is easy to machine. It has a balanced combination of strength, toughness, and weldability.
316 is a hard, high-carbon steel that is at risk of cracking if machined thoroughly. It is also very difficult to weld and can only be used to join parts that are very small or do not require heavy loads. It has high toughness and excellent wear and tear resistance, making it suitable for blade and automotive parts applications.
Each alloy has its advantages depending on your needs, and you must know their physical properties before buying or choosing a company.
Grade | Alloy 304 | Alloy 316 |
Density | 7.93 g/cm3 | 8.00 g/cm3 |
Melting Point | 1400-1450℃ | 1370-1400℃ |
Thermal Expansion | 17.3×10^-6/℃ | 16.5×10^-6/℃ |
Thermal Conductivity | 16.2-24.9W/(m·K) | 16.2-21.5W/(m·K) |
Electrical Conductivity | 1.45×10^6 – 1.6×10^6 S/m | 1.29×10^6 – 1.4×10^6 S/m |
Magnetic Properties | Yes | No |
The mechanical properties of stainless steel include strength, hardness, toughness, ductility, plasticity and other indicators. Different alloys have different mechanical properties. The following are the mechanical properties of 304 and 316 steel:
Alloy/Properties | 304 | 316 |
Tensile Strength | 515 MPa | 590 MPa |
Yield Strength | 1400-1450℃ | 1370-1400℃ |
Hardness | 17.3×10^-6/℃ | 16.5×10^-6/℃ |
Elongation | 16.2-24.9W/(m·K) | 16.2-21.5W/(m·K) |
Elastic Modulus | 1.45×10^6 – 1.6×10^6 S/m | 1.29×10^6 – 1.4×10^6 S/m |
304 is more heat resistant than 316 due to its higher chromium content and is easy to weld. Its application range is wide and it can even be used in places with extreme temperatures, although it can be used at lower temperatures than 316.
In contrast to the easy welding of 304, the hardening process of 316 stainless steel makes it very difficult to weld. Even incorrectly shaped parts can cause difficulties before they break. Therefore, parts made of 316 can only be welded by professionals, as they usually break when welded by amateurs or hobbyists.
Due to the high chromium content, 304 has a better surface flatness than 316. However, 316 tends to be harder and requires more force. In addition, in stamped or forged parts, 316 is prone to defects, especially when the forging temperature is high.
Welding alloys with a higher carbon content than pure steel can cause cracks where there is too much tension, and this is also the case with 304. This means that if you are welding workpieces made of 304, you should use TIG welding to ensure that cracks do not appear. No cracking when welding. If you are welding workpieces made of 316, direct MIG welding is recommended because the weld is more likely to withstand higher loads.
Therefore, if you are welding parts made of 304 or 316, use TIG welding instead of MIG. If you want to use an AWS welder, choose the right TIG or MIG welding wire. When using TIG welding, make sure that the anodizing work is not covered too much so that the weld is hidden behind the anodized surface. Otherwise, the weld will not be able to withstand higher loads.
304 is more resistant to oxidation than 316. Therefore, 304 is better suited for exterior applications, although corrosion is a concern in seawater. This means that 316 should be used when corrosion is a concern in a marine environment.
Due to its higher carbon content, 316 is easily oxidized by the atmosphere. Therefore, if it is not grounded during the forming or welding process, 316 may corrode. 316 can also rust if the atmosphere is moist and salty, which makes it unsuitable for exterior uses.
The high carbon content of 316 stainless steel makes it less suitable for welding interiors than 304 stainless steel. However, due to its hardening treatment and heat resistance, it can be safely used by professional welders. The hardening treatment also makes it less susceptible to creep, which in other words means it is more durable.
304 stainless steel has excellent corrosion resistance and can resist corrosion from corrosive media such as general atmosphere, water, acid, alkali and salt at room temperature.
Its corrosion resistance mainly comes from the 18% chromium contained in it, which reacts with oxygen in the air to form a dense chromium oxide film (Cr2O3), which can effectively prevent further oxidation corrosion of the steel.
Compared with 304 stainless steel, 316 stainless steel has better corrosion resistance in chloride ion media and can resist chloride corrosion and pitting. In addition, 316 stainless steel also has good acid resistance, alkali resistance and high temperature resistance, and can be used in harsh corrosive environments.
304 stainless steel is one of the most common stainless steels. It has excellent corrosion resistance, high temperature resistance and good processing performance, so it is widely used in the following fields:
Architectural decoration: 304 stainless steel has a smooth surface and corrosion resistance, and is widely used in indoor and outdoor decoration, stair handrails, wall decoration, elevator internal installation, etc.
Food processing industry: 304 stainless steel has excellent corrosion resistance and hygiene, so it is widely used in food processing equipment, kitchen utensils, tableware, etc.
Medical instruments: 304 stainless steel is clean, so it is widely used in the manufacture of medical equipment, surgical instruments, surgical implants, etc. Machinery manufacturing: 304 stainless steel has excellent strength and corrosion resistance, and is widely used in the manufacture of various mechanical parts, bearings, valves, etc.
Petrochemical, chemical and marine engineering: 304 stainless steel can withstand high temperature, high pressure and corrosive media, so it is widely used in petrochemical, marine engineering, chemical equipment and other fields.
Transportation fields such as automobiles and trains: The corrosion resistance and strength of 304 stainless steel make it an important part of automobiles and trains, such as exhaust pipes, doors, roofs, etc.
316 stainless steel is a kind of steel with good corrosion resistance and high temperature resistance, which is widely used in the following fields:
Chemical industry: 316 stainless steel can resist corrosion from a variety of chemicals, so it is used in the chemical industry to manufacture storage tanks, pipes, valves and other equipment.
Food processing industry: 316 stainless steel is one of the commonly used materials in the food processing industry, used to manufacture containers, equipment, pipes, etc.
Medical instruments: 316 stainless steel is used to manufacture medical devices, surgical tools, surgical implants, etc. due to its corrosion resistance, high strength and high temperature resistance.
Shipbuilding: 316 stainless steel has good corrosion resistance in seawater, so it is widely used in shipbuilding and marine engineering.
Construction industry: 316 stainless steel has the characteristics of high strength, beauty and corrosion resistance, and is widely used in architectural decoration, building components, indoor furniture and other fields.
Cosmetic packaging: Cosmetic bottles, powder boxes, lipstick tubes and other cosmetics made of 316 stainless steel have exquisite appearance and are durable, which can meet consumers' requirements for beauty and quality.
JN is a 304 and 316 stainless steel plate, pipes, bars, fittings, flanges, forgings, and pipe spools supplier, with 20+ years experience. If you have stainless steel, duplex steel and nickel alloy needs, please contact me immediately.
