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Stainless Steel 321/321H Fasteners are engineered for high-temperature structural integrity and resistance to intergranular corrosion, making them essential in demanding environments such as aerospace assemblies, chemical processing equipment, and thermal power plants. These fasteners are stabilized with titanium, which prevents carbide precipitation during welding or prolonged exposure to elevated temperatures, ensuring long-term mechanical stability under stress.
Manufactured in compliance with standards such as ASTM A193, ASTM A194, DIN 1.4541, and ISO specifications, these fasteners deliver reliable performance in both oxidizing and mildly corrosive environments. The 321H variant offers higher carbon content, improving creep resistance in elevated temperature service conditions above 500°C.
Industries such as oil & gas refineries, exhaust systems, and heat exchanger manufacturing rely on these fasteners for their combination of strength, weldability, and thermal resistance. KK Fasteners supplies these components to global industrial buyers with full material traceability and strict dimensional control, ensuring consistency across critical engineering applications.
| Parameter | Specification |
|---|---|
| Material | Stainless Steel 321 / 321H (Austenitic, Titanium Stabilized) |
| Grade Options | UNS S32100 / UNS S32109 |
| Size Range | M3 to M100 / 1/8” to 4” |
| Thread Types | Metric, UNC, UNF, BSW, BSF |
| Standards | ASTM A193, ASTM A194, DIN 1.4541, ISO 3506 |
| Surface Finish | Bright, Passivated, Polished, Black Oxide |
| Fastener Types | Bolts, Nuts, Screws, Studs, Washers |
| Tensile Strength | ≥ 515 MPa (321), ≥ 585 MPa (321H) |
| Hardness | HRB 95 max |
| Grade | C | Mn | Si | P | S | Cr | N | Ni | Ti |
|---|---|---|---|---|---|---|---|---|---|
|
SS 321 |
0.08 max |
2.0 max |
1.0
max |
0.045 max |
0.030 max |
17.00-19.00 |
0.10 max |
9.00-12.00 |
5(C+N) – 0.70 max
|
|
SS 321H |
0.04 – 0.10 |
2.0 max |
1.0 max |
0.045 max |
0.030 max |
17.00-19.00 |
0.10 max |
9.00-12.00 |
4(C+N) – 0.70 max
|
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
|
321/321H |
8.0 g/cm3 |
1457 °C (2650 °F)
|
Psi – 75000 , MPa – 515 |
Psi – 30000 , MPa – 205 |
35 %
|
| Grade | WERKSTOFF NR. | UNS | JIS | EN |
|---|---|---|---|---|
|
SS 321
|
1.4541
|
S32100
|
SUS 321 |
X6CrNiTi18-10
|
|
SS 321H
|
1.4878 |
S32109 |
SUS 321H
|
X12CrNiTi18-9
|
All measurements in millimeters
| NOMINAL SIZE (D) | BODY DIAMETER | HEAD THICKNESS ASTM A193 | ACRO ASTMA193 THE FLATS | ACRO ASTM A193 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
|
Stainless Steel 321/321H Fasteners are used in high-temperature and corrosive environments where structural integrity and long-term reliability are critical.
Stainless Steel 321/321H Fasteners are manufactured using controlled cold forging and precision CNC machining to achieve dimensional accuracy and consistent grain structure. Heat treatment is carefully managed to preserve titanium stabilization and mechanical integrity.
Each batch undergoes rigorous inspection, including tensile testing, hardness verification, and metallographic analysis to ensure compliance with ASTM and ISO standards. Surface finish and threading accuracy are verified using calibrated gauges.
KK Fasteners implements full lot traceability and material certification (MTC) with every shipment, ensuring transparency for critical engineering procurement. Products are also tested for corrosion resistance and load performance under simulated operating conditions, reinforcing reliability for industrial applications.
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Stainless Steel 321/321H Fasteners are titanium-stabilized austenitic stainless steel fastening components designed for high-temperature and corrosive environments. SS 321 offers excellent weldability and oxidation resistance, while 321H provides higher carbon content for improved creep strength in elevated temperature service conditions such as heat exchangers, furnace assemblies, and refinery equipment.
SS 321 contains a lower carbon content, making it more suitable for general high-temperature and welded applications where corrosion resistance is critical. SS 321H has a higher carbon level, which enhances tensile strength and creep resistance at temperatures above 500°C, making it ideal for pressure vessels and continuous thermal load environments.
These fasteners are commonly manufactured in compliance with ASTM A193, ASTM A194, DIN 1.4541, ISO 3506, and relevant BS standards. These specifications ensure dimensional accuracy, mechanical strength, and material traceability for global industrial applications.
They are widely used in aerospace exhaust systems, chemical processing plants, oil and gas refineries, power generation boilers, heat exchangers, and furnace equipment. Their ability to maintain strength under high heat makes them suitable for continuous thermal cycling and corrosive operating conditions.
A reliable supplier should provide certified raw materials, ISO-compliant manufacturing processes, full test reports, and traceability documentation. Global export capability and consistent quality control are also essential. KK Fasteners supplies engineered fastening solutions with strict inspection standards and international compliance support.
Stainless Steel 321/321H Fasteners are critical for high-temperature engineering reliability where standard stainless steels fail under thermal stress. KK Fasteners supports global OEMs with precision-manufactured fasteners backed by material certification and engineering-grade quality control.
For technical datasheets, pricing, or custom manufacturing requirements, contact KK Fasteners to request a quote or speak with the engineering team for project-specific support.
