Alloy 218 Bolts are high-strength industrial fasteners engineered for demanding load-bearing and high-temperature environments where standard carbon steel bolts fail to perform. Manufactured from alloy steel with controlled chemical composition, these bolts provide superior tensile strength, fatigue resistance, and durability under cyclic loading conditions. They are widely used in sectors such as oil & gas, petrochemical processing, power generation, and heavy machinery fabrication where mechanical reliability is critical.

These bolts are typically produced in compliance with ASTM and ISO standards, offering compatibility with global engineering specifications. Precision threading, controlled heat treatment, and consistent dimensional tolerances ensure reliable performance in critical assemblies.
KK Fasteners supplies Alloy 218 Bolts to international markets with full material traceability, ensuring compliance with project-specific requirements across industries that demand both strength and long-term operational integrity.
| Parameter | Details |
|---|---|
| Material | Alloy Steel (Alloy 218) |
| Grade | ASTM A193 B7 / B16 (Equivalent Alloy Grades) |
| Size Range | M6 to M100 / ¼” to 4” |
| Thread Type | Metric, UNC, UNF, BSW, BSF |
| Standards | DIN 933, DIN 931, ISO 4014, ISO 4017, ASTM A193 |
| Surface Finish | Black Oxide, Zinc Plated, Hot Dip Galvanized, PTFE Coated |
| Types | Hex Bolts, Heavy Hex Bolts, Stud Bolts, Fully Threaded |
| Tensile Strength | Up to 860 MPa – 1035 MPa |
| Hardness | 24–35 HRC (depending on heat treatment) |
| Alloy 218 | Ni | C | Mo | Mn | Si | N | Cr |
| 9.00 – 8.00 | 0.10 | 0.75 | 9 – 7 | 4.5 – 3.5 | 0.18 – 0.08 | 18 – 16 |
| Density | Melting Point | Yield Strength |
Tensile Strength | Elongation |
| 8.08 |
1425 °C |
379 MPa | 724 MPa | 35 % |
| STANDARD | UNS | WERKSTOFF NR. | AFNOR | EN | JIS | SIS | GOST |
| Alloy 218 | A01218 | 1.4547 | Z1 CNDU 20.18.06Az | X1CrNiMoCuN20-18-7 | – | 2378 | – |
All measurements in millimeters
NOMINAL SIZE (D) |
BODY DIAMETER |
BOLT HEAD THICKNESS |
ACROSS THE FLATS |
ACROSS CORNERS |
||||
|---|---|---|---|---|---|---|---|---|
D (MAX) |
D (MIN) |
H (MAX) |
H (MIN) |
F (MAX) |
F (MIN) |
C (MAX) |
C (MIN) |
|
m10 |
10.00 |
9.78 |
6.63 |
6.17 |
17.00 |
15.73 |
18.48 |
17.77 |
m12 |
12.00 |
11.73 |
7.76 |
4.24 |
19.00 |
17.73 |
20.78 |
20.03 |
m14 |
14.00 |
13.73 |
9.09 |
8.51 |
22.00 |
20.67 |
24.25 |
23.35 |
m16 |
16.00 |
15.73 |
10.32 |
9.68 |
24.00 |
23.67 |
27.71 |
26.75 |
m20 |
20.00 |
19.67 |
12.88 |
12.12 |
30.00 |
29.16 |
34.64 |
32.95 |
m24 |
24.00 |
23.67 |
15.44 |
14.56 |
36.00 |
35.00 |
41.57 |
39.55 |
m30 |
30.00 |
29.67 |
19.48 |
17.92 |
46.00 |
45.00 |
53.12 |
50.85 |
m36 |
36.00 |
35.61 |
23.38 |
21.63 |
55.00 |
53.80 |
63.51 |
60.79 |
m42 |
42.00 |
41.38 |
26.97 |
25.03 |
65.00 |
62.90 |
75.06 |
71.71 |
m48 |
48.00 |
47.38 |
31.07 |
28.93 |
75.00 |
72.60 |
86.60 |
82.76 |
m56 |
56.00 |
55.26 |
36.2 |
33.80 |
85.00 |
82.20 |
98.15 |
93.71 |
m64 |
64.00 |
63.26 |
41.32 |
38.68 |
95.00 |
91.80 |
109.70 |
104.65 |
m72 |
72.00 |
71.26 |
46.45 |
43.55 |
105.00 |
101.40 |
121.24 |
115.60 |
m80 |
80.00 |
79.26 |
51.58 |
48.42 |
115.00 |
111.00 |
132.72 |
126.54 |
m90 |
90.00 |
89.13 |
57.74 |
54.26 |
130.00 |
125.50 |
150.11 |
143.07 |
m100 |
90.00 |
99.13 |
63.9 |
60.10 |
145.00 |
140.00 |
167.43 |
159.60 |
| MM THREADS AS PER IS 1363/67 | ||||||||||
| APPROXIMATE WEIGHT IN KGS FOR 100 NOS | ||||||||||
| LENGTH | DIAMETER | |||||||||
| M 5 | M 6 | M 8 | M 10 | M 12 | M 14 | M 16 | M 18 | M 20 | M 22 | |
| 16 mm | 0.448 | 0.743 | 1.590 | 3.211 | ||||||
| 20 mm | 0.598 | 0.812 | 1.711 | 3.411 | 4.892 | |||||
| 25 mm | 0.660 | 0.897 | 1.871 | 3.660 | 5.252 | 8.170 | ||||
| 30 mm | 0.737 | 1.010 | 2.070 | 3.912 | 5.574 | 9.690 | 10.707 | 18.657 | ||
| 35 mm | 0.804 | 1.120 | 2.271 | 4.223 | 5.974 | 10.000 | 11.416 | 16.026 | 19.608 | |
| 40 mm | 0.881 | 1.230 | 2.470 | 4.533 | 6.410 | 10.288 | 12.107 | 16.667 | 20.747 | |
| 45 mm | 0.958 | 1.340 | 2.671 | 4.840 | 6.859 | 10.504 | 12.821 | 17.241 | 21.739 | |
| 50 mm | 1.030 | 1.450 | 2.870 | 5.155 | 7.299 | 11.261 | 13.624 | 17.857 | 22.727 | 28.409 |
| 55 mm | 1.560 | 3.071 | 5.464 | 7.740 | 11.628 | 14.409 | 18.868 | 23.810 | 30.120 | |
| 60 mm | 1.670 | 3.270 | 5.774 | 8.183 | 12.255 | 15.244 | 20.000 | 25.126 | 32.051 | |
| 65 mm | 1.781 | 3.472 | 6.083 | 8.621 | 12.626 | 16.026 | 21.008 | 26.455 | 34.014 | |
| 70 mm | 1.890 | 3.671 | 6.394 | 9.058 | 12.987 | 16.835 | 22.124 | 27.778 | 35.461 | |
| 75 mm | 2.000 | 3.873 | 6.702 | 9.506 | 13.228 | 17.606 | 23.256 | 29.070 | 39.063 | |
| 80 mm | 2.111 | 4.072 | 7.013 | 10.000 | 13.889 | 18.248 | 24.510 | 30.303 | 40.000 | |
| 90 mm | 4.472 | 7.634 | 10.917 | 14.925 | 19.841 | 26.042 | 33.113 | 41.667 | ||
| 100 mm | 4.873 | 8.251 | 11.820 | 16.340 | 21.459 | 27.778 | 35.714 | 46.296 | ||
| 110 mm | 8.881 | 12.723 | 17.730 | 23.041 | 31.250 | 38.168 | 47.170 | |||
| 120 mm | 9.506 | 13.624 | 18.797 | 24.631 | 32.895 | 40.984 | 50.000 | |||
| 130 mm | 10.101 | 14.535 | 20.000 | 26.316 | 34.722 | 43.478 | 52.632 | |||
| 140 mm | 10.707 | 15.432 | 20.833 | 27.933 | 35.461 | 46.296 | 55.556 | |||
| 150 mm | 11.312 | 16.340 | 22.222 | 29.412 | 37.594 | 48.544 | 58.824 | |||
| 160 mm | 11.905 | 17.241 | 24.272 | 31.056 | 40.984 | 50.505 | 61.728 | |||
| 170 mm | 12.500 | 18.116 | 32.680 | 53.191 | 64.935 | |||||
| 180 mm | 13.123 | 19.011 | 26.882 | 34.247 | 55.556 | 67.568 | ||||
| 190 mm | 13.736 | 19.920 | 35.971 | 58.140 | 70.423 | |||||
| 200 mm | 14.327 | 20.833 | 29.586 | 37.594 | 49.020 | 60.976 | 73.529 | |||
| 220 mm | 15.528 | 22.624 | 40.650 | 65.789 | 79.365 | |||||
| 240 mm | 16.722 | 24.510 | 43.860 | 71.429 | 84.746 | |||||
| 250 mm | 17.301 | 25.381 | 45.455 | 74.627 | 87.719 | |||||
| 260 mm | 17.921 | 26.316 | 47.170 | 76.923 | 90.909 | |||||
| 280 mm | 19.157 | 28.090 | 50.505 | 81.967 | 98.039 | |||||
| 300 mm | 20.325 | 29.940 | 53.763 | 87.719 | 104.167 | |||||
| 320 mm | 31.646 | 56.818 | 92.593 | |||||||
| 340 mm | 33.557 | 60.241 | 98.039 | |||||||
| 360 mm | 35.211 | 63.291 | 104.167 | |||||||
| 380 mm | 37.037 | 66.667 | 108.696 | |||||||
| 400 mm | 39.063 | 69.444 | 113.636 | |||||||
Alloy 218 Bolts are used in high-load, high-temperature, and structurally critical applications where mechanical failure is not an option.
Alloy 218 Bolts are manufactured using hot forging or cold forging processes, followed by CNC machining to achieve precise dimensional accuracy. Controlled heat treatment processes enhance mechanical properties such as tensile strength and hardness.
Quality assurance includes dimensional inspection using calibrated gauges, hardness testing (Rockwell scale), and tensile testing to verify load capacity. Surface finish and coating thickness are also inspected to ensure compliance with project specifications.
At KK Fasteners, each batch undergoes strict quality checks with full lot traceability and documentation aligned with ISO 9001 standards, ensuring consistent product reliability across global shipments.

Explore our comprehensive range of products, ensuring you find the perfect solution for your specific requirements.

Save money without compromising on quality, thanks to our competitive prices and cost-effective options.

Personalized assistance, prompt responses, and a commitment to meeting your needs, making your purchase process seamless.
Alloy 218 bolts are high-strength alloy steel fasteners designed for demanding industrial applications. They are engineered to handle high tensile loads, elevated temperatures, and dynamic stress, making them suitable for critical assemblies in sectors like oil & gas, power generation, and heavy engineering.
These bolts are manufactured from alloy steel with a controlled chemical composition, typically aligned with ASTM A193 B7 or B16 grades. This material offers excellent tensile strength, hardness, and resistance to fatigue, ensuring reliable performance in high-pressure and high-temperature environments.
Alloy 218 bolts are produced in accordance with international standards such as ASTM A193, DIN 933, DIN 931, ISO 4014, and ISO 4017. These standards ensure dimensional accuracy, mechanical strength, and compatibility with global engineering systems
Selection depends on factors such as load requirements, operating temperature, and exposure conditions. B7-grade equivalents are suitable for general high-pressure use, while B16-grade variants perform better in elevated temperature environments. Thread type and surface coating should also match the application.
A reliable supplier should offer ISO-certified production, full material traceability, and compliance with ASTM standards. Manufacturers with global export experience, such as KK Fasteners, typically provide test certificates, consistent quality, and dependable supply for large-scale industrial projects.
Alloy 218 Bolts play a critical role in maintaining structural integrity in high-load and high-temperature environments. With controlled manufacturing processes and strict quality validation, they offer consistent performance across demanding applications.
KK Fasteners supports global buyers with traceable, standards-compliant fasteners and flexible customization options. For project inquiries or technical specifications, request a quote or connect with the engineering team to evaluate the right solution for your application.