- Call Us+91 9819454781
- Email Usinquiry@kkfasteners.com
- WhatsApp+91 9819454781
Stainless Steel 347/347H Screws are engineered fastening components designed for high-temperature and corrosive environments where standard austenitic grades may fail due to carbide precipitation. These screws are stabilized with niobium, which enhances resistance to intergranular corrosion and improves performance in elevated temperature conditions. Commonly manufactured to ASTM A193 B8C and DIN/ISO standards, they are widely used in petrochemical processing, power generation, and heat exchanger assemblies.
The primary advantage of Stainless Steel 347/347H Screws lies in their ability to maintain structural integrity under continuous thermal exposure, particularly in applications exceeding 500°C. The 347H variant offers higher carbon content, delivering improved creep resistance for prolonged service conditions.
KK Fasteners supplies these screws to global industrial buyers, ensuring consistent material traceability, compliance with international standards, and reliable performance in critical applications.
| Parameter | Details |
|---|---|
| Material Grades | Stainless Steel 347, 347H |
| Standards | ASTM A193 B8C, ASTM A194, DIN 933, ISO 4017, BS 3692 |
| Size Range | M3 to M64 / 1/8" to 2" |
| Thread Type | Metric (Coarse/Fine), UNC, UNF, BSW |
| Length | 6 mm to 300 mm |
| Surface Finish | Plain, Passivated, PTFE Coated, Polished |
| Type Variants | Hex Head, Socket Head, Machine Screws, Self-Tapping Screws |
| Tensile Strength | 515 – 750 MPa |
| Hardness | Max 201 HB |
| Grade | C | Mn | Si | P | S | Cr | Ni | Ti |
| 347 | 0.08 max. | 2.00 max. | 0.75 max. | 0.045 max. | 0.03 max. | 17.0 – 19.0 | 9.0-13.0 | 10 x C min.(1.00 max.) |
| 347H | 0.04 – 0.10 | 2.00 max. | 0.75 max. | 0.045 max. | 0.03 max. | 17.0 – 19.0 | 9.0-13.0 | 8 x C min. 1.00 max.) |
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 7.96 g/cm3 | 1450 °C | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 40 % |
| STANDARD | WERKSTOFF NR. | UNS |
| SS 347 | 1.4550 | S34700 |
| SS 347H | 1.4961 | S34709 |
Flat Head Machine Screws
| Nominal Size | A | H | J | T | M | G | N | Phillips Driver Size | |||||
| Head Diameter | Height of Head | Width of Slot | Depth of Slot | Dimensions of Recess | |||||||||
| Diameter | Depth | Width | |||||||||||
| Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | ||
| 2 4 5 6 7* 8 9* 10 12 14* 1/4 5/16 3/8 1/2 | .172 .225 .252 .279 .305 .332 .358 .385 .438 .491 .507 .635 .762 .875 | 147 .195 .220 .244 .268 .292 .316 .340 .389 .437 .452 .568 .685 775 | .051 .067 .075 .083 .091 .100 .108 .116 .132 .148 .153 .191 .230 .223 | .040 .055 .062 .069 .076 .084 .091 .098 .112 .127 .131 .165 .200 .198 | .031 .039 .043 .048 .048 .054 .054 .060 .067 .075 .075 .084 .094 .106 | .023 .031 .035 .039 .039 .045 .045 .050 .056 .064 .064 .072 .081 .091 | .023 .030 .034 .038 .041 .045 .049 .053 .060 .068 .070 .088 .106 .103 | .015 .020 .022 .024 .027 .029 .032 .034 .039 .044 .046 .058 .070 .065 | .102 .128 .154 .174 .182 .189 .258 .204 .268 .283 .283 .365 .393 .424 | .089 .115 .141 .161 .169 .176 .245 .191 .255 .270 .270 .352 .380 .411 | .063 .089 .086 .106 .114 .121 .146 .136 .156 .171 .171 .216 .245 .276 | .017 .018 .027 .029 .030 .031 .034 .032 .036 .039 .035 .061 .065 .069 | 1 1 2 2 2 2 2 2-3* 3 3 3 4 4 4 |
| Nominal Size | A | W | H | F | U | J | T | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Width Across Flats | Width Across Corners | Height of Head | Diameter of Washer | Thickness of Washer | Width of Slot | Depth of Slot | |||||||
| Max. | Min. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | |
| 4 6 7 8 10 12 14 1/4 5/16 3/8 | .187 .250 .250 .250 .312 .312 .438 .375 .500 .562 | .181 .244 .244 .244 .305 .305 .428 .367 .489 .551 | .202 .272 .272 .272 .340 .340 .409 .409 .545 .614 | .060 .093 .093 .110 .120 .155 .190 .190 .230 .295 | .049 .080 .080 .096 .105 .139 .172 .172 .208 .270 | .243 .328 .328 .348 .414 .432 .520 .520 .676 .780 | .225 .302 .302 .322 .384 .398 .480 .480 .624 .720 | .019 .025 .029 .031 .031 .039 .050 .050 .055 .063 | .011 .015 .017 .019 .019 .022 .030 .030 .035 .037 | .039 .048 .048 .054 .060 .067 .075 .075 .084 .094 | .031 .039 .039 .045 .050 .056 .064 .064 .072 .081 | .042 .053 .062 .074 .080 .103 .111 .111 .134 .168 | .025 .033 .040 .052 .057 .077 .083 .083 100 .131 |
|
Nominal
|
Thread.
|
Hex Socket Size
|
Body diameter and Head height
|
Head Dia
|
Soc. length
|
||
|
Size
|
Pitch
|
Max
|
Min
|
Max
|
Min
|
||
|
J
|
D /H
|
A
|
K
|
||||
|
M3
|
0.5
|
2.50
|
3.00
|
2.86
|
5.50
|
5.20
|
1.3
|
|
M4
|
0.70
|
3.00
|
4.00
|
3.82
|
7.00
|
6.64
|
2.00
|
|
M5
|
0.8
|
4.00
|
5.00
|
4.82
|
8.50
|
8.14
|
2.70
|
|
M6
|
1.0
|
5.00
|
6.00
|
5.82
|
10.00
|
9.64
|
3.30
|
|
M8
|
1.25
|
6.00
|
8.00
|
7.78
|
13.00
|
12.57
|
4.3
|
|
M10
|
1.5
|
8.00
|
10.00
|
9.78
|
16.00
|
15.57
|
5.50
|
|
M12
|
1.75
|
10.00
|
12.00
|
11.73
|
18.00
|
17.57
|
6.60
|
|
M16
|
2.0
|
14.00
|
16.00
|
15.73
|
24.00
|
23.48
|
8.80
|
|
M20
|
2.5
|
17.00
|
20.00
|
19.67
|
30.00
|
29.48
|
10.70
|
|
M24
|
3.0
|
19.00
|
24.00
|
23.67
|
36.00
|
35.38
|
12.90
|
Stainless Steel 347/347H Screws are used in high-temperature and corrosion-sensitive applications where long-term reliability is critical.
Stainless Steel 347/347H Screws are used in high-temperature and corrosion-sensitive applications where long-term reliability is critical.
Production of Stainless Steel 347/347H Screws involves cold forging or CNC machining depending on size and complexity. Threads are rolled or cut to meet ISO and DIN dimensional tolerances, ensuring consistent fit and performance. Heat treatment processes are controlled to maintain the desired mechanical properties and corrosion resistance.
Quality checks include dimensional inspection using calibrated gauges, hardness testing, tensile strength verification, and surface finish analysis. Each batch is traceable through mill test certificates (MTC). KK Fasteners follows ISO 9001-certified quality management systems, along with compliance to RoHS and REACH standards, ensuring that every shipment meets international procurement requirements.
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.
Stainless Steel 347/347H screws are high-temperature austenitic fasteners stabilized with niobium to prevent intergranular corrosion. They are specifically designed for applications involving elevated temperatures and corrosive environments, such as petrochemical processing, power plants, and heat exchanger systems.
The key difference is carbon content. SS 347H has higher carbon, which enhances creep resistance and strength at elevated temperatures. SS 347 is preferred for corrosion resistance after welding, while 347H is better suited for prolonged high-temperature service.
These screws are typically manufactured to ASTM A193 B8C, along with dimensional standards such as DIN 933, ISO 4017, and BS 3692. These standards ensure proper material composition, mechanical properties, and dimensional accuracy.
Selection depends on operating temperature, load conditions, and environmental exposure. SS 347 is suitable for moderate heat and corrosion resistance, while 347H is recommended for high-temperature environments requiring enhanced creep strength and durability.
A reliable manufacturer should offer ISO-certified production, full material traceability, and compliance with international standards like ASTM and DIN. Suppliers such as KK Fasteners also provide consistent export quality, inspection documentation, and global delivery support.
Stainless Steel 347/347H Screws offer a dependable solution for high-temperature fastening challenges where material stability and corrosion resistance are critical. With controlled manufacturing processes and global supply capability, KK Fasteners supports project-specific requirements across industries. For detailed specifications, pricing, or technical assistance, request a quote or connect with the engineering team today.
