The second most common type of stainless steel is 316. The physical and mechanical properties are very similar to 304 stainless steel, but the key difference is that 316 stainless steel incorporates about 2-3 percent molybdenum. Molybdenum has the ability to protect against chlorides and other industrial solvents, which gives the steel a stronger corrosion resistance. Again it is an austenitic grade with the addition of 2–3% molybdenum which further improves corrosion resistance. It is often referred to as a marine grade stainless steel because of its effective resistance to chloride corrosion in comparison to other stainless steel grades.
The material has superior welding and forming qualities. Grade 316 will require post-weld annealing to promote maximum corrosion resistance, though this is not necessary if Type 316L is used.
The steel was initially produced for the paper producing industry as it has been shown to be highly resistant to the sulphur compounds used in paper processing.
Typical applications for this material are now widespread due to its superior corrosion resistance properties when compared to Grade 304. Type 316 stainless can be found in heat exchangers, pharmaceutical equipment, dairies and breweries, marine fittings, coastal architectural fascia and fittings and in food preparation areas.
316 & 316L steel plate and pipes have common properties and are often stocked with Dual Certification, where it is determined that both have properties and composition which comply with both steel types.
Type 316H is excluded from this scenario by virtue of the fact that unlike 316 & 316L, 316H is engineered to work in elevated working temperatures.
316L
Type 316L is the low carbon version of 316 stainless. With the addition of molybdenum, the steel is popular for use in severe corrosion environments due to the materials immunity from boundary carbide precipitation (sensitisation).
The material is widely used in heavy gauge welded components and weld annealing is only required where the material is for use in high stress environments. 316L has an extensive variety of uses especially in marine applications due to the materials high corrosion resistance.
Benefits of using Type 316L Stainless Steel
- Low carbon content eliminates carbon precipitation in the welding process
- Can be used in severe corrosive environments
- Improved anti–corrosion scope due to added Molybdenum
- Weld annealing only required in high stress applications
- Very similar to Grade 316 in chemical composition and mechanical properties
316H
Type 316H is a higher carbon variant of 316 making the steel more suitable for use in applications where elevated temperatures are present.
Stabilised Grade 316Ti offers similar qualities.
The increased carbon content delivers a greater tensile and yield strength. The austenitic structure of the material also gives this grade excellent toughness, even down to cryogenic temperatures.
Benefits of using Type 316H Stainless Steel
Increased carbon content heat resistant qualities
Greater tensile yield strength
Greater short and long term creep strength
Chemical Compostion of 316 stainless steel
The chemical composition of ASTM A240 Grade 316/316L Stainless Steel is outlined in the following table| Grade | Scope | C | Mn | Si | P | S | Cr | Mo | Ni | N |
|---|---|---|---|---|---|---|---|---|---|---|
| 316 | Min | - | - | - | 0 | - | 16 | 2 | 10 | - |
| Max | 0.08 | 2 | 0.75 | 0.045 | 0.03 | 18 | 3 | 14 | 0.1 | |
| 316L | Min | - | - | - | - | - | 16 | 2 | 10 | - |
| Max | 0.03 | 2 | 0.75 | 0.045 | 0.03 | 18 | 3 | 14 | 0.1 | |
| 316H | Min | 0.04 | 0.04 | 0 | - | - | 16 | 2 | 10 | - |
| max | 0.1 | 0.1 | 0.75 | 0.045 | 0.03 | 18 | 3 | 14 | - |
Mechanical and Physical Properties of 316 Stainless steel
| Grade | Tensile Str | Yield Str 0.2% Proof | Elong | Hardness | |
|---|---|---|---|---|---|
| (MPa) min | (MPa) min | (% in 50mm) min | Rockwell B (HR B) max | Brinell (HB) max | |
| 316 | 515 | 205 | 40 | 95 | 217 |
| 316L | 485 | 170 | 40 | 95 | 217 |
| 316H | 515 | 205 | 40 | 95 | 217 |
Specification of 316 Steel plate
| Thickness of cold rolled steel plate | Thickness of galvanized steel sheet | Wearing plate+Corrosion resistance plate | Galvanized coil+Galvanized coil | Ction volume | Stainless steel plate | Thick plate |
|---|---|---|---|---|---|---|
| 0.1mm | 0.1mm | 1.5mm | 0.1mm | 0.1mm | 1.5mm | 18mm |
| 0.2mm | 0.2mm | 2.0mm | 0.2mm | 0.2mm | 2.0mm | 20mm |
| 0.3mm | 0.3mm | 2.5mm | 0.3mm | 0.3mm | 2.5mm | 22mm |
| 0.4mm | 0.4mm | 2.75mm | 0.4mm | 0.4mm | 2.75mm | 25mm |
| 0.5mm | 0.5mm | 3.0mm | 0.5mm | 0.5mm | 3.0mm | 28mm |
| 0.6mm | 0.6mm | 3.5mm | 0.6mm | 0.6mm | 3.5mm | 30mm |
| 0.7mm | 0.7mm | 3.75mm | 0.7mm | 0.7mm | 3.75mm | 32mm |
| 0.8mm | 0.8mm | 4.0mm | 0.8mm | 0.8mm | 4.0mm | 35mm |
| 0.9mm | 0.9mm | 4.5mm | 0.9mm | 0.9mm | 4.5mm | 40mm |
| 1.0mm | 1.0mm | 4.75mm | 1.0mm | 1.0mm | 4.75mm | 42mm |
| 1.2mm | 1.2mm | 5.0mm | 1.2mm | 1.2mm | 5.0mm | 45mm |
| 1.3mm | 1.3mm | 5.5mm | 1.3mm | 1.3mm | 5.5mm | 48mm |
| 1.4mm | 1.4mm | 5.75mm | 1.4mm | 1.4mm | 5.75mm | 50mm |
| 1.5mm | 1.5mm | 6.0mm | 1.5mm | 1.5mm | 6.0mm | 52mm |
| 1.6mm | 1.6mm | 6.5mm | 1.6mm | 1.6mm | 6.5mm | 55mm |
| 1.8mm | 1.8mm | 6.75mm | 1.8mm | 1.8mm | 6.75mm | 58mm |
| 1.9mm | 1.9mm | 7.5mm | 1.9mm | 1.9mm | 7.5mm | 60mm |
| 2.0mm | 2.0mm | 7.75mm | 2.0mm | 2.0mm | 7.75mm | 62mm |
| 2.1mm | 2.1mm | 8.0mm | 2.1mm | 2.1mm | 8.0mm | 65mm |
| 2.2mm | 2.2mm | 8.5mm | 2.2mm | 2.2mm | 8.5mm | 68mm |
| 2.4mm | 2.4mm | 8.75mm | 2.4mm | 2.4mm | 8.75mm | 70mm |
| 2.5mm | 2.5mm | 9.5mm | 2.5mm | 2.5mm | 9.5mm | 72mm |
| 2.6mm | 2.6mm | 9.75mm | 2.6mm | 2.6mm | 9.75mm | 75mm |
| 2.7mm | 2.7mm | 10mm | 2.7mm | 2.7mm | 10mm | 80mm |
| 2.8mm | 2.8mm | 10.5mm | 2.8mm | 2.8mm | 10.5mm | 82mm |
| 3.0mm | 3.0mm | 11.5mm | 3.0mm | 3.0mm | 11.5mm | 85mm |
| 3.2mm | 3.2mm | 11.75mm | 3.2mm | 3.2mm | 11.75mm | 90mm |
| 3.4mm | 3.4mm | 12mm | 3.4mm | 3.4mm | 12mm | 100mm |
| 3.5mm | 3.5mm | 12.5mm | 3.5mm | 3.5mm | 12.5mm | 110mm |
| 3.6mm | 3.6mm | 12.75mm | 3.6mm | 3.6mm | 12.75mm | 120mm |
| 3.8mm | 3.8mm | 13.75mm | 3.8mm | 3.8mm | 13.75mm | 140mm |
| 4.0mm | 4.0mm | 14mm | 4.0mm | 4.0mm | 14mm | 150mm |
| 4.2mm | 4.2mm | 14.5mm | 4.2mm | 4.2mm | 14.5mm | 160mm |
| 4.5mm | 4.5mm | 14.75mm | 4.5mm | 4.5mm | 14.75mm | 170mm |
| 4.6mm | 4.6mm | 15mm | 4.6mm | 4.6mm | 15mm | 180mm |
| 4.8mm | 4.8mm | 15.5mm | 4.8mm | 4.8mm | 15.5mm | 190mm |
| 5.0mm | 5.0mm | 16mm | 5.0mm | 5.0mm | 16mm | 200mm |
Processing Technology Of 316 Steel plate
With the development of science and technology and industry, the materials put forward higher requirements, such as higher strength, resistance to high temperature, high pressure, low temperature, corrosion resistance, wear and other special physical and chemical properties of the requirements, carbon steel has been unable to fully meet the requirements.
Deficiency of carbon steel:
(1) Low hardenability. In general, the maximum quenching diameter of carbon steel water quenching is only 10mm-20mm.
(2) Relatively low strength and buckling. For example, the σ S of ordinary carbon steel Q235 steel is 235MPa, while the σ S of low alloy structural steel 16Mn is more than 360MPa. The σ S /σ B of 40 steel is only 0.43, which is much lower than that of alloy steel.
(3) Poor tempering stability. Because of the poor tempering stability, carbon steel in the quenching and tempering treatment, in order to ensure higher strength to use a lower tempering temperature, so that the toughness of steel is low; In order to ensure better toughness, the strength of high tempering temperature is low, so the comprehensive mechanical properties of carbon steel is not high.
(4) Can not meet the requirements of special performance. Carbon steel in oxidation resistance, corrosion resistance, heat resistance, low temperature resistance, wear resistance and special electromagnetic and other aspects are often poor, can not meet the needs of special performance.
Applications of 316 Stainless Steel
The addition of Molybdenum in 316 makes it much more corrosion resistant than similar alloys. Due to its superior resistance to corrosion, 316 is one of the staple metals for marine environments. 316 stainless steel is also utilized in hospitals because of its durability and cleanliness.
Fun fact: The Chicago Bean is made from 316 stainless steel!
Common Applications:
- Water-handling: boilers, water heaters
- Marine parts- boat rails, wire rope, boat ladders
- Medical Equipment
- Chemical processing equipment
304 Vs 316 Stainless Steel
The high levels of chromium and nickel found in 304 and 316 stainless steel provides them with a strong resistance to heat, abrasion, and corrosion. Not only are they known for their resistance to corrosion, they are also known for their clean appearance and overall cleanliness.
Both types of stainless steel appear in wide-ranging industries. As the most common grade of stainless steel, 304 is considered the standard “18/8” stainless. 304 stainless steel is widely used because it is durable and easy to form into various forms such as stainless steel sheet, stainless steel plate, stainless steel bar, and stainless steel tube. 316 steel’s resistance to chemicals and marine environments makes it a popular choice among manufacturers.
Heat Resistance
Heat resistance is an important factor to consider when comparing the different grades of stainless steel. The melting range of 304 is around 50 to 100 degrees Fahrenheit higher than 316. Although the melting range of 304 is higher than 316, they both have good resistance to oxidization in intermittent service up to 870°C (1500℉) and in continuous service at 925°C (1697℉).
- 304 SS: Handles high heat well, but continuous use at 425-860 °C (797-1580 °F) may cause corrosion.
- 316 SS: Performs best in temperatures above 843 ℃ (1550 ℉) and below 454 ℃ (850°F)
Price
What makes 316 more expensive than 304 stainless steel? The increase of nickel content and the addition of molybdenum in 316 makes it more expensive than 304. On average, the price of 316 stainless steel 40% higher than the price of 304 SS.
Which is Better?
When comparing 304 stainless steel vs 316, they both have pros and cons to consider when deciding which one to use for different applications. For instance, 316 stainless steel is more resistant than 304 to salt and other corrosives. So, if you are manufacturing a product that will often face exposure to chemicals or a marine environment, 316 is the better choice.
On the other hand, if you are manufacturing a product that does not need strong corrosion resistance, 304 is a practical and economical choice. For many applications, 304 and 316 are actually interchangeable.