SMO 254 is a super austenitic grade stainless steel. The primary alloying metals in this grade of stainless steel are molybdenum and nitrogen. Because of a high content of molybdenum and nitrogen, in the alloy, the fasteners offer high resistance to pitting and crevice corrosion. Further, this grade of stainless steel is has an impact toughness, two times that of grade 316.
Table of Content
Additionally, SMO 254 Material Fasteners have a high tensile strength as compared to conventional austenitic stainless steels such as 316L & is known to possess excellent workability as well. UNS S31254 6mo Fasteners offers excellent resistance to stress related corrosion cracking as the fasteners have been cold formed. The fasteners may also be used without the need to re-anneal at testing up to 120°C. The lack of sulphur along with its high hardening rate, makes this alloy difficult to machine. Although, using sharp overpowered machine tools, positive feeds, good amount of lubrication along with slow speeds is known to offer good machining results.
Hot working operations like Forging, upsetting and other operations can be performed between a temperature range of 982 - 1149°C (1800 - 2100°F). heating the alloy beyond this temperature will cause the 1.4547 Bolts to scale and will also reduce the workability of the material.The alloy for SMO 254 can be annealed by heating it to a temperature range between 1149 °C - 1204°C following which the fasteners need to be water quenched. Annealing the alloy ASTM A479 UNS S31254 increases its corrosion resistance.
Although cold working the 254 SMO Fasteners is difficult because of its high hardening rate, cold working the alloy leads to an increase in strength and toughness. The alloy can be cold worked using all conventional methods.Since the alloy of 254 SMO Bolts does not respond to heat treatment, the only way to harden the alloy is by cold reduction.
Applications of the SMO 254 Fasteners include Desalination plant equipment, Seawater handling systems, Control and instrumentation tubes, Paper and pulp, Chemical processing, Flue gas desulphurisation units in power plants. In some applications, the SMO 254 Material Bolts have replaced or substituted high nickel and titanium content alloys by proving to be a cost effective alternative.
| Specifications of 254 SMO Fasteners | ASTM A479 & ASME SA479 |
| Standard of 254 SMO Fasteners | DIN, ASTM, BS and all International Standards |
| Length of 254 SMO Fasteners | 3 mm to 200 mm |
| 254 SMO Nuts Size | M3 - M56 | 3/6" to 2" | Custom Sizes |
| 254 SMO Bolt / Screw Size | M3 - M56 | 3/6" to 2" | Custom Sizes |
| 254 SMO Machine Screws Size | M1.6 - M12 |
| 254 SMO Washers Size | M3 - M56 | 3/6" to 2" | Custom Sizes |
| Stainless Steel Grades | SMO 254 |
| 254 SMO Fasteners Type | Socket Screw, Hex Set Screw, Cap Screw, Machine Screw, Wing Screw, Spring Washers, Washers, Studs, Marine Anchors, Anchors, Hexagon Nut,U- Bolts, Anchor Bolt, Mushroom Head Square Neck Bolts, J Bolts,Eye Bolt,Structural Bolts, Bolts, Nuts, Sockets, Screws, Allen Cap screw, Nut, Hex Coupling Nut, Hex Nut, Square Nut, Hex Domed Cap Nuts, Hex Head Bolts, Stud Bolts, Socket Hexagon Head Screw, Pan Head Screw, Socket Head Cap Screw, Wing Screw, T-Head Bolts, Foundation Bolts,Screw, Studs |
254 SMO Hex Bolt Dimension

**All measurements in millimeters**
NOMINAL SIZE (D) |
BODY DIAMETER |
HEAD THICKNEASTM A479 |
ACROASTM A479 THE FLATS |
ACROASTM A479 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 |
254 SMO Nuts Size Chart
Nut Size (mm) |
Diameter* (mm) |
Height (mm) |
||
|---|---|---|---|---|
Hex Nut |
Jam Nut |
Nylock Nut |
||
2 |
4 |
1.6 |
1.2 |
- |
2.5 |
5 |
2 |
1.6 |
- |
3 |
5.5 |
2.4 |
1.8 |
4 |
4 |
7 |
3.2 |
2.2 |
5 |
5 |
8 |
4 |
2.7 |
5 |
6 |
10 |
5 |
3.2 |
6 |
7 |
11 |
5.5 |
3.5 |
- |
8 |
13 |
6.5 |
4 |
8 |
10 |
17 |
8 |
5 |
10 |
12 |
19 |
10 |
6 |
12 |
14 |
22 |
11 |
7 |
14 |
16 |
24 |
13 |
8 |
16 |
18 |
27 |
15 |
9 |
18.5 |
20 |
30 |
16 |
10 |
20 |
* This is the diameter across the flats. It is also the size of wrench to use. |
||||

Size |
USS |
SAE |
||||
|---|---|---|---|---|---|---|
Inside Diameter (A) |
Outside Diameter (B) |
Thickness (C) |
Inside Diameter (A) |
Outside Diameter (B) |
Thickness (C) |
|
#2 |
- |
- |
- |
3/32" |
1/4" |
0.020" |
#4 |
- |
- |
- |
1/8" |
5/16" |
0.032" |
#6 |
- |
- |
- |
5/32" |
3/8" |
0.049" |
#8 |
- |
- |
- |
3/16" |
7/16" |
0.049" |

**All measurements in millimeters**
Nominal Size or Basic Major Thread Diameter |
F |
G |
H |
||||||
Width Across Flats |
Width Across Corners |
Thickness |
|||||||
Basic |
Max |
Min |
Max |
Min |
Basic |
Max |
Min |
||
1/4 |
.2500 |
7/16 |
.438 |
.428 |
.505 |
.488 |
7/32 |
.226 |
.212 |
5/16 |
.3125 |
1/2 |
.500 |
.489 |
.577 |
.557 |
17/64 |
.273 |
.258 |
3/8 |
.3750 |
9/16 |
.562 |
.551 |
.650 |
.628 |
21/64 |
.337 |
.479 |
7/16 |
.4375 |
11/16 |
.688 |
.675 |
.794 |
.768 |
3/8 |
.385 |
.365 |
1/2 |
.5000 |
3/4 |
.750 |
.736 |
.866 |
.840 |
7/16 |
.448 |
.427 |
9/16 |
.5625 |
7/8 |
.875 |
.861 |
1.010 |
.982 |
31/64 |
.496 |
.473 |
5/8 |
.6250 |
15/16 |
.938 |
.922 |
1.083 |
1.051 |
35/64 |
.559 |
.535 |
3/4 |
.7500 |
1-1/8 |
1.125 |
1.088 |
1.299 |
1.240 |
41/64 |
.665 |
.617 |
7/8 |
.8750 |
1-5/16 |
1.312 |
1.269 |
1.516 |
1.447 |
3/4 |
.776 |
.724 |
1 |
1.0000 |
1-1/2 |
1.500 |
1.450 |
1.732 |
1.653 |
55/64 |
.887 |
.831 |
1-1/8 |
1.1250 |
1-11/16 |
1.688 |
1.631 |
1.949 |
1.859 |
31/32 |
.999 |
.939 |
1-3/8 |
1.3750 |
2-1/16 |
2.062 |
1.994 |
2.382 |
2.273 |
1-11/64 |
1.206 |
1.138 |
1-1/2 |
1.500 |
2-1/4 |
2.250 |
2.175 |
2.598 |
2.480 |
1-9/32 |
1.ASTM A194 GR. 8 |
1.245 |
1-5/8 |
1.6250 |
2-7/16 |
2.438 |
2.356 |
2.815 |
2.686 |
1-25/64 |
1.429 |
1.353 |
1-3/4 |
1.7500 |
2-5/8 |
2.625 |
2.538 |
3.031 |
2.893 |
1-1/2 |
1.540 |
1.460 |
2 |
2.0000 |
3 |
3.000 |
2.900 |
3.464 |
3.306 |
1-23/32 |
1.763 |
1.675 |
2-1/4 |
2.2500 |
3-3/8 |
3.375 |
3.263 |
3.897 |
3.719 |
1-15/16 |
1.986 |
1.890 |
2-1/2 |
2.5000 |
3-3/4 |
3.750 |
3.625 |
4.330 |
4.133 |
2-5/32 |
2.209 |
2.105 |
2-3/4 |
2.7500 |
4-1/8 |
4.125 |
3.988 |
4.763 |
4.546 |
2-3/8 |
2.431 |
2.319 |
Bolt Size
|
USS
|
SAE
|
||||
OD (in.)
|
ID (in.)
|
Thickness
|
OD (in.)
|
ID (in.)
|
Thickness
|
|
1/8 (#6)
|
-
|
-
|
-
|
0.375
|
0.156
|
.036/.065
|
5/32 (#8)
|
-
|
-
|
-
|
0.438
|
0.188
|
.036/.065
|
3/16 (#10)
|
0.560
|
0.250
|
.036/.065
|
0.500
|
0.220
|
.036/.065
|
7/32 (#12)
|
-
|
-
|
-
|
0.562
|
0.250
|
.051/.080
|
1/4 (#14)
|
0.734
|
0.312
|
.051/.080
|
0.625
|
0.281
|
.051/.080
|
5/16
|
0.875
|
0.375
|
.064/.104
|
0.688
|
0.344
|
.051/.080
|
3/8
|
1.000
|
0.438
|
.064/.104
|
0.812
|
0.406
|
.051/.080
|
7/16
|
1.250
|
0.500
|
.064/.104
|
0.922
|
0.469
|
.051/.080
|
1/2
|
1.375
|
0.562
|
.086/.132
|
1.062
|
0.531
|
.074/.121
|
9/16
|
1.469
|
0.625
|
.086/.132
|
1.156
|
0.594
|
.074/.121
|
5/8
|
1.750
|
0.688
|
.108/.160
|
1.312
|
0.656
|
.074/.121
|
3/4
|
2.000
|
0.812
|
.122/.177
|
1.469
|
0.812
|
.108/.160
|
7/8
|
2.250
|
0.938
|
.136/.192
|
1.750
|
0.938
|
.108/.160
|
1
|
2.500
|
1.062
|
.136/.192
|
2.000
|
1.062
|
.108/.160
|
1 1/8
|
2.750
|
1.250
|
.136/.192
|
2.250
|
1.250
|
.108/.160
|
1 1/4
|
3.000
|
1.375
|
.136/.192
|
2.500
|
1.375
|
.136/.192
|
1 3/8
|
3.250
|
1.500
|
.153/.213
|
2.750
|
1.500
|
.136/.213
|
1 1/2
|
3.500
|
1.625
|
.153/.213
|
3.000
|
1.625
|
.153/.213
|
1 5/8
|
3.750
|
1.750
|
.153/.213
|
-
|
-
|
-
|
1 3/4
|
4.000
|
1.875
|
.153/.213
|
-
|
-
|
-
|
1 7/8
|
4.250
|
2.000
|
.153/.213
|
-
|
-
|
-
|
2
|
4.500
|
2.125
|
.153/.213
|
-
|
-
|
-
|
2 1/4
|
4.750
|
2.375
|
.320/.248
|
-
|
-
|
-
|
2 1/2
|
5.000
|
2.625
|
.210/.280
|
-
|
-
|
-
|
2 3/4
|
5.250
|
2.875
|
.228/.410S
|
-
|
-
|
-
|
3
|
5.500
|
3.125
|
.249/.327
|
-
|
-
|
-
|
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 |

Other Types Of 254 SMO Fasteners
Stainless Steel Fasteners |
Stainless Steel Stud Bolts |
254 SMO Bolts and Nuts |
SIS 2378 Anchor Bolts Stockist |
SIS 2378 Stainless Steel Hex Nuts Torque |
254 SMO Tower Bolts Wholesaler |
254 SMO Hex Nuts |
UNS S31254 Stainless Steel U Bolts Supplier |
EN X1CrNiMoCuN20-18-7 Stainless Steel Stud Strength |
SIS 2378 Eye Bolt Manufacturer |
254 SMO Lock Nuts |
SIS 2378 Stainless Steel Stove Bolts Exporter |
254 SMO Tek Screw |
SMO 254 Roofing Screw |
UNS S31254 Stainless Steel Tie Bar |
254 SMO Threaded Rod |
ASME SA254 SMO Spherical Washer |
AISI SMO 254 Dock Washer |
254 SMO Star Washer |
SMO 254 Lock Washer |
| SMO 254 | Ni | C | Mo | Mn | Si | Fe | Cu | S | P | Cr |
| 17.5 – 18.5 |
0.02 max | 6 – 6.5 |
1 max | 0.8 max | – | 0.5 – 1 | 0.01 max | 0.03 max | 19.5 – 20.5 |
| STANDARD | UNS | WERKSTOFF NR. | AFNOR | EN | JIS | SIS | GOST |
| SMO 254 | S31254 | 1.4547 | Z1 CNDU 20.18.06Az | X1CrNiMoCuN20-18-7 | – | 2378 | – |
| Density | Melting Point | Yield Strength (0.2%Offset) | Tensile Strength | Elongation |
| 8.0 g/cm3 | 1320-1390 ℃ | 300 | 650 | 35 % |
Properties |
Metric |
Imperial |
|---|---|---|
Density |
8 g/cm3 |
0.289 lb/in3 |