SS 316 bolts and nuts are fasteners made from AISI 316 stainless steel, an austenitic alloy known for its excellent corrosion resistance, especially in marine, chemical, and highly chlorinated environments. Compared to 304 stainless steel, 316 stainless steel contains molybdenum (Mo), which significantly enhances its resistance to pitting, crevice corrosion, and high temperatures. These fasteners are ideal for applications where reliability, corrosion resistance, and mechanical strength are critical.
Because of their chemical composition, SS316 bolts and nuts have excellent resistance to a wide range of chemicals, including seawater, chemical solutions, acids and alkalis found in food processing environments. While ordinary carbon steel bolts rust and corrode quickly in the marine environment, SS316 bolts and nuts are resistant to seawater for a long period of time, maintaining the stability of the connection.
316 bolts and A193 B8M bolts have the same strength requirements and excellent corrosion resistance.B8M grade bolts are made of highly corrosion resistant stainless steel. ZIZI is a leading manufacturer and supplier of different types. Specifications include ASTM and ASME A193 and 194. There are different standards for bolt types according to DIN, ASTM, BS and UNS S31600.
SS 316 Bolts and Nuts Specification
| Specifications | ASTM A 193 ASME SA 193 |
| Standard | DIN, ASTM, BS and all International Standards |
| Length | 3 mm to 200 mm |
| Size | M3 – M56 | 3/6″ to 2″ | Custom Sizes |
| Type | Hex Head Bolts, Square Bolts, U bolts, Eye bolts, T bolt, Hex Bolt, Lag Bolts, Countersunk Bolts, Hex Head nuts, Square nuts, Lock nuts, Eye nuts, wing nuts, T nuts, Panel Nuts, Coupling Nuts, Dome nuts, Acorn Nuts. |
Reference Standards
ASTM A153/A153M : Specification for Zinc Coating Hot Dip Galvanizing on Fasteners.
ASTM A194/A194M : Specification for Carbon and Alloy Steel Nuts for ASTM A193 Bolts.
ASTM A320/A320M : Specification for alloy-steel and stainless steel bolting for low temperature service.
ASME B18.2.1 : Square and Hex Bolts and Screws.
ASME B18.2.3.3M : Metric Heavy Hex Screws
ASME B18.3 : Hexagon Socket and Spline Socket Screws
ASME B18.3.1M : Metric Socket Head Cap Screws
Performance of SS 316 Bolts and Nuts
Excellent Corrosion Resistance: This is the most notable feature of SS 316. Especially in chloride environments such as seawater, brine, chlorine, and various acidic or alkaline chemicals, it exhibits stronger resistance to pitting and crevice corrosion than SS 304. This property makes it known as “marine grade” stainless steel.
High Strength and Toughness: SS 316 bolts and nuts have high tensile strength and yield strength, can withstand large loads, and maintain good mechanical properties even at high temperatures.
High Temperature Resistance: Although mainly known for its corrosion resistance, SS 316 also has good high temperature resistance.
Non-magnetic: In most cases, SS 316 is non-magnetic, but it may be slightly magnetic after certain processing processes.
Stainless Steel 316 Nut Thread Types
ASTM A193 UNS S31600 Fastener Chemical Composition
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni |
| 316 | 0.08 max | 2.0 max | 1.0 max | 0.045 max | 0.030 max | 16.00 – 18.00 | 2.00 – 3.00 | 11.00 – 14.00 |
| 316L | 0.035 max | 2.0 max | 1.0 max | 0.045 max | 0.030 max | 16.00 – 18.00 | 2.00 – 3.00 | 10.00 – 14.00 |
| 316H | 0.10 max | 0.10 max | 0.75 max | 0.045 max | 0.030 max | 16.00 – 18.00 | 2.00 – 3.00 | 10.00 – 14.00 |
Mechanical Properties of SS 316 Bolts and Nuts
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 316/316L/316H | 8.0 g/cm3 | 1400 °C (2550 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 35% |
ASTM A193 SS B8M / 316 Bolts and Nuts Equivalent Grades
| STANDARD | WERKSTOFF NR. | UNS | JIS | BS | GOST | AFNOR | EN |
| SS 316 | 1.4401 / 1.4436 | S31600 | SUS 316 | 316S31 / 316S33 | – | Z7CND17-11-02 | X5CrNiMo17-12-2 / X3CrNiMo17-13-3 |
SS UNS S31600 Bolts Dimension
| NOMINAL SIZE (D) | BODY DIAMETER | HEAD THICKNEASTM A193 | ACROASTM A193 THE FLATS | ACROASTM A193 CORNERS | ||||
| D (MAX) | D (MIN) | H (MAX) | H (MIN) | F (MAX) | F (MIN) | C (MAX) | C (MIN) | |
| m10 | 10 | 9.78 | 6.63 | 6.17 | 17 | 15.73 | 18.48 | 17.77 |
| m12 | 12 | 11.73 | 7.76 | 4.24 | 19 | 17.73 | 20.78 | 20.03 |
| m14 | 14 | 13.73 | 9.09 | 8.51 | 22 | 20.67 | 24.25 | 23.35 |
| m16 | 16 | 15.73 | 10.32 | 9.68 | 24 | 23.67 | 27.71 | 26.75 |
| m20 | 20 | 19.67 | 12.88 | 12.12 | 30 | 29.16 | 34.64 | 32.95 |
| m24 | 24 | 23.67 | 15.44 | 14.56 | 36 | 35 | 41.57 | 39.55 |
| m30 | 30 | 29.67 | 19.48 | 17.92 | 46 | 45 | 53.12 | 50.85 |
| m36 | 36 | 35.61 | 23.38 | 21.63 | 55 | 53.8 | 63.51 | 60.79 |
| m42 | 42 | 41.38 | 26.97 | 25.03 | 65 | 62.9 | 75.06 | 71.71 |
| m48 | 48 | 47.38 | 31.07 | 28.93 | 75 | 72.6 | 86.6 | 82.76 |
| m56 | 56 | 55.26 | 36.2 | 33.8 | 85 | 82.2 | 98.15 | 93.71 |
| m64 | 64 | 63.26 | 41.32 | 38.68 | 95 | 91.8 | 109.7 | 104.65 |
| m72 | 72 | 71.26 | 46.45 | 43.55 | 105 | 101.4 | 121.24 | 115.6 |
| m80 | 80 | 79.26 | 51.58 | 48.42 | 115 | 111 | 132.72 | 126.54 |
| m90 | 90 | 89.13 | 57.74 | 54.26 | 130 | 125.5 | 150.11 | 143.07 |
| m100 | 90 | 99.13 | 63.9 | 60.1 | 145 | 140 | 167.43 | 159.60 |
ASTM A193 UNS S31600 Nuts Dimension
| Nominal Size | Basic Major Diameter of Thread | Width Across Flats, F | Width Across Corners, G | Thickness Hex Nuts, H | Thickness Jam Nuts, H1 | Maximum Run out of Bearing Surface to Thread Axis, FIM | ||||||
| Hex Nuts Specified Proof Load | Hex Jam Nuts | |||||||||||
| Up to 1 5 0 , 0 0 0 psi | 1 5 0 , 0 0 0 psi and Greater | All Strength Levels | ||||||||||
| Min | Max. | Min | Max. | Min | Max. | Min | Max. | |||||
| 1⁄4 | 0 . 2 5 0 0 | 0 . 4 2 8 | 0 . 4 3 8 | 0 . 4 8 8 | 0 . 5 0 5 | 0 . 2 1 2 | 0 . 2 2 6 | 0 . 1 5 0 | 0 . 1 6 3 | 0 . 0 1 5 | 0 . 0 1 0 | 0 . 0 1 5 |
| 5⁄1 6 | 0 . 3 1 2 5 | 0 . 4 8 9 | 0 . 5 0 0 | 0 . 5 5 7 | 0 . 5 7 7 | 0 . 2 5 8 | 0 . 2 7 3 | 0 . 1 8 0 | 0 . 1 9 5 | 0 . 0 1 6 | 0 . 0 1 1 | 0 . 0 1 6 |
| 3⁄8 | 0 . 3 7 5 0 | 0 . 5 5 1 | 0 . 5 6 3 | 0 . 6 2 8 | 0 . 6 5 0 | 0 . 3 2 0 | 0 . 3 3 7 | 0 . 2 1 0 | 0 . 2 2 7 | 0 . 0 1 7 | 0 . 0 1 2 | 0 . 0 1 7 |
| 7⁄1 6 | 0 . 4 3 7 5 | 0 . 6 7 5 | 0 . 6 8 8 | 0 . 7 6 8 | 0 . 7 9 4 | 0 . 3 6 5 | 0 . 3 8 5 | 0 . 2 4 0 | 0 . 2 6 0 | 0 . 0 1 8 | 0 . 0 1 3 | 0 . 0 1 8 |
| 1⁄2 | 0 . 5 0 0 0 | 0 . 7 3 6 | 0 . 7 5 0 | 0 . 8 4 0 | 0 . 8 6 6 | 0 . 4 2 7 | 0 . 4 4 8 | 0 . 3 0 2 | 0 . 3 2 3 | 0 . 0 1 9 | 0 . 0 1 4 | 0 . 0 1 9 |
| 9⁄1 6 | 0 . 5 6 2 5 | 0 . 8 6 1 | 0 . 8 7 5 | 0 . 9 8 2 | 1 . 0 1 0 | 0 . 4 7 3 | 0 . 4 9 6 | 0 . 3 0 1 | 0 . 3 2 4 | 0 . 0 2 0 | 0 . 0 1 5 | 0 . 0 2 0 |
| 5⁄8 | 0 . 6 2 5 0 | 0 . 9 2 2 | 0 . 9 3 8 | 1 . 0 5 1 | 1 . 0 8 3 | 0 . 5 3 5 | 0 . 5 5 9 | 0 . 3 6 3 | 0 . 3 8 7 | 0 . 0 2 1 | 0 . 0 1 6 | 0 . 0 2 1 |
| 3⁄4 | 0 . 7 5 0 0 | 1 . 0 8 8 | 1 . 1 2 5 | 1 . 2 4 0 | 1 . 2 9 9 | 0 . 6 1 7 | 0 . 6 6 5 | 0 . 3 9 8 | 0 . 4 4 6 | 0 . 0 2 3 | 0 . 0 1 8 | 0 . 0 2 3 |
| 7⁄8 | 0 . 8 7 5 0 | 1 . 2 6 9 | 1 . 3 1 2 | 1 . 4 4 7 | 1 . 5 1 6 | 0 . 7 2 4 | 0 . 7 7 6 | 0 . 4 5 8 | 0 . 5 1 0 | 0 . 0 2 5 | 0 . 0 2 0 | 0 . 0 2 5 |
| 1 | 1 . 0 0 0 0 | 1 . 4 5 0 | 1 . 5 0 0 | 1 . 6 5 3 | 1 . 7 3 2 | 0 . 8 3 1 | 0 . 8 8 7 | 0 . 5 1 9 | 0 . 5 7 5 | 0 . 0 2 7 | 0 . 0 2 2 | 0 . 0 2 7 |
| 1 1⁄8 | 1 . 1 2 5 0 | 1 . 6 3 1 | 1 . 6 8 8 | 1 . 8 5 9 | 1 . 9 4 9 | 0 . 9 3 9 | 0 . 9 9 9 | 0 . 5 7 9 | 0 . 6 3 9 | 0 . 0 3 0 | 0 . 0 2 5 | 0 . 0 3 0 |
| 1 1⁄4 | 1 . 2 5 0 0 | 1 . 8 1 2 | 1 . 8 7 5 | 2 . 0 6 6 | 2 . 1 6 5 | 1 . 0 3 0 | 1 . 0 9 4 | 0 . 6 8 7 | 0 . 7 5 1 | 0 . 0 3 3 | 0 . 0 2 8 | 0 . 0 3 3 |
| 1 3⁄8 | 1 . 3 7 5 0 | 1 . 9 9 4 | 2 . 0 6 2 | 2 . 2 7 3 | 2 . 3 8 2 | 1 . 1 3 8 | 1 . 2 0 6 | 0 . 7 4 7 | 0 . 8 1 5 | 0 . 0 3 6 | 0 . 0 3 1 | 0 . 0 3 6 |
| 1 1⁄2 | 1 . 5 0 0 0 | 2 . 1 7 5 | 2 . 2 5 0 | 2 . 4 8 0 | 2 . 5 9 8 | 1 . 2 4 5 | 1 . 3 1 7 | 0 . 8 0 8 | 0 . 8 8 0 | 0 . 0 3 9 | 0 . 0 3 4 | 0 . 0 3 9 |
| 1 5⁄8 | 1 . 6 2 5 0 | 2 . 3 5 0 | 2 . 4 3 0 | 2 . 6 7 9 | 2 . 8 0 5 | 1 . 3 6 4 | 1 . 4 1 6 | 0 . 8 6 8 | 0 . 9 4 4 | 0 . 0 4 4 | 0 . 0 3 8 | 0 . 0 4 4 |
| 1 3⁄4 | 1 . 7 5 0 0 | 2 . 5 3 8 | 2 . 6 2 5 | 2 . 8 9 3 | 3 . 0 3 1 | 1 . 4 6 0 | 1 . 5 4 0 | 0 . 9 2 9 | 1 . 0 0 9 | 0 . 0 4 8 | 0 . 0 4 1 | 0 . 0 4 8 |
| 1 7⁄8 | 1 . 8 7 5 0 | 2 . 7 2 2 | 2 . 8 1 3 | 3 . 1 0 3 | 3 . 2 4 7 | 1 . 5 6 7 | 1 . 6 5 1 | 0 . 9 8 9 | 1 . 0 7 3 | 0 . 0 5 1 | 0 . 0 4 4 | 0 . 0 5 1 |
| 2 | 2 . 0 0 0 0 | 2 . 9 0 0 | 3 . 0 0 0 | 3 . 3 0 6 | 3 . 4 6 4 | 1 . 6 7 5 | 1 . 7 6 3 | 1 . 0 5 0 | 1 . 1 3 8 | 0 . 0 5 5 | 0 . 0 4 7 | 0 . 0 5 5 |
| 21⁄4 | 2 . 2 5 0 0 | 3 . 2 6 3 | 3 . 3 7 5 | 3 . 7 1 9 | 3 . 8 9 7 | 1 . 8 9 0 | 1 . 9 8 6 | 1 . 1 5 5 | 1 . 2 6 7 | 0 . 0 6 1 | 0 . 0 5 2 | 0 . 0 6 1 |
| 21⁄2 | 2 . 5 0 0 0 | 3 . 6 2 5 | 3 . 7 5 0 | 4 . 1 3 3 | 4 . 3 3 0 | 2 . 1 0 5 | 2 . 2 0 9 | 1 . 4 0 1 | 1 . 4 2 7 | 0 . 0 6 8 | 0 . 0 5 8 | 0 . 0 6 8 |
| 23⁄4 | 2 . 7 5 0 0 | 3 . 9 8 8 | 4 . 1 2 5 | 4 . 5 4 6 | 4 . 7 6 3 | 2 . 3 1 9 | 2 . 4 3 1 | 1 . 5 2 2 | 1 . 5 5 6 | 0 . 0 7 4 | 0 . 0 6 4 | 0 . 0 7 4 |
| 3 | 3 . 0 0 0 0 | 4 . 3 5 0 | 4 . 5 0 0 | 4 . 9 5 9 | 5 . 1 9 6 | 2.534 | 2.654 | 1 . 6 4 3 | 1 . 6 8 5 | 0 . 0 8 1 | 0 . 0 7 0 | 0 . 0 8 1 |
| 31⁄4 | 3 . 2 5 0 0 | 4 . 7 1 3 | 4 . 8 7 5 | 5 . 3 7 3 | 5 . 6 2 9 | 2 . 7 4 9 | 2 . 8 7 7 | 1 . 7 4 8 | 1 . 8 1 4 | 0 . 0 8 7 | 0 . 0 7 5 | 0 . 0 8 7 |
| 31⁄2 | 3 . 5 0 0 0 | 5 . 0 7 5 | 5 . 2 5 0 | 5 . 7 8 6 | 6 . 0 6 2 | 2.964 | 3 . 1 0 0 | 1 . 8 7 0 | 1 . 9 4 3 | 0 . 0 9 4 | 0 . 0 8 1 | 0 . 0 9 4 |
| 33⁄4 | 3 . 7 5 0 0 | 5 . 4 3 8 | 5 . 6 2 5 | 6 . 1 9 9 | 6 . 4 9 5 | 3 . 1 7 8 | 3 . 3 2 2 | 1 . 9 9 0 | 2 . 0 7 2 | 0 . 1 0 0 | 0 . 0 8 7 | 0 . 1 0 0 |
| 4 | 4 . 0 0 0 0 | 5 . 8 0 0 | 6 . 0 0 0 | 6 . 6 1 2 | 6 . 9 2 8 | 3 . 3 9 3 | 3 . 5 4 5 | 2 . 1 1 2 | 2 . 2 0 1 | 0 . 1 0 7 | 0 . 0 9 3 | 0 . 1 0 7 |
SS 316 Bolts and Nuts Advantages:
Excellent corrosion resistance: especially strong resistance to corrosive media such as chlorides, acids and alkalis, which greatly extends the service life.
High strength and durability: able to withstand heavy loads and harsh working conditions, not easy to deform or break.
Good processability: Although slightly more difficult to process than some other materials, but SS 316 Bolts and Nuts still can be cold working, hot forging and other ways to create a variety of fasteners.
Hygienic and aesthetic: smooth surface, easy to clean, and has a good appearance.
Versatile: Suitable for use in a variety of harsh environments.
SS 316 Bolts and Nuts Disadvantages:
Higher Cost: SS 316 bolts and nuts are more expensive than SS 304 or carbon steel bolts, primarily due to the addition of molybdenum.
Difficulty in machining: Due to its hardness and toughness, machining SS 316 can be more difficult than other materials, requiring more specialized tools and techniques.
Not completely immune to corrosion: Despite high corrosion resistance, pitting or crevice corrosion may occur under extreme corrosive conditions, such as prolonged exposure to high concentrations of chlorides or crevices in strong acid environments.
Strength Limitations: Higher grades of alloy steel may be required for specific applications requiring very high tensile or fatigue strength.
Application Areas
Marine and coastal environments
Chemical and petrochemical industries
Food processing and pharmaceutical industries
Construction and infrastructure
Textile and paper industries
Aerospace
Automobile manufacturing
Energy nuclear power plants