ASTM A194 Grade 8F Specification

Standard Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or both.

ASTM A194 specification covers a variety of carbon, alloy, and martensitic stainless steel nuts in the size range 1/4 through 4 in. and metric M6 through M100 nominal. It also covers austenitic stainless steel nuts in the size range 1/4 in. and M6 nominal and above. These nuts are intended for high-pressure or high-temperature service, or both.

ASTM A194 Grade 8F Nut Grades

Grade
Tensile Class
Raw Material
B5
4-6% Chromium Ferritic Steel
B6
13% Chromium Ferritic Steel
B6X
13% Chromium Ferritic Steel
B7
Chromium Molybdenum Alloy Steel, Quenched & Tempered
B7M
Chromium Molybdenum Alloy Steel, Quenched & Tempered
B16
Chromium-molybdenum-vanadium Alloy Steel, Quenched & Tempered
B8
Class 1
AISI 304 Stainless Steel, Carbide Solution Treated
B8
Class 2
AISI 304 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8A
AISI 304 Stainless Steel, Carbide solution treated in the finished condition
B8C
Class 1
AISI 347 Stainless Steel, Carbide Solution Treated
B8C
Class 2
AISI 347 Stainless Steel, Carbide Solution Treated and Strained Hardened
B8CA
AISI 347 Stainless Steel, Carbide Solution Treated in Finished Condition
B8M
Class 1
AISI 316 Stainless Steel, Carbide Solution Treated
B8M
Class 2
AISI 316 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8MA
AISI 316 Stainless Steel, Carbide Solution Treated in Finished Condition
B8M2
AISI 316 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8M3
AISI 316 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8P
Class 1
AISI 305 Stainless Steel, Carbide Solution Treated
B8P
Class 2
AISI 305 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8PA
AISI 305 Stainless Steel, Carbide Solution Treated in Finished Condition
B8N
AISI 304N Stainless Steel, Carbide Solution Treated
B8N
AISI 304N Stainless Steel, Carbide Solution Treated and Strain Hardened
B8MLCuN
AISI 304N Stainless Steel, Carbide Solution Treated
B8MLCuN
UNS S31254 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8MLCuNA
UNS S31254 Stainless Steel, Carbide Solution Treated
B8T
Class 1
AISI 321 Stainless Steel, Carbide Solution Treated
B8T
Class 2
AISI 321 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8TA
AISI 321 Stainless Steel, Carbide Solution Treated in Finished Condition
B8R
Nitronic 50/UNS S20910 Stainless Steel, Carbide Solution Treated
B8RA
Nitronic 50/UNS S20910 Stainless Steel, Carbide Solution Treated in Finished Condition
B8S
Nitronic 60/UNS S21800 Stainless Steel, Carbide Solution Treated
B8SA
Nitronic 60/UNS S21800 Stainless Steel, Carbide Solution Treated
B8LN
AISI 304LN Stainless Steel, Carbide Solution Treated
B8LNA
AISI 304LN Stainless Steel, Carbide Solution Treated in Finished Condition
B8MLN
AISI 316LN Stainless Steel, Carbide Solution Treated
B8MLNA
AISI 316LN Stainless Steel, Carbide Solution Treated in Finished Condition
B8CLN
AISI 347LN Stainless Steel, Carbide Solution Treated
B8CLNA
AISI 347LN Stainless Steel, Carbide Solution Treated in Finished Condition

ASTM A194 Grade 8F Chemical Components

Grade
Material
UNS
Number
C, %
Mn, %
Ph, %
S, %
Si, %
Cr, %
Ni, %
Mo, %
Ti, %
Cb & Ta, %
N, %
Other Elements, %
1
Carbon
0.15 min
1.000
0.040
0.050
0.400
-
-
-
-
-
-
-
2, 2HM, & 2H
Carbon
0.40 min
1.000
0.040
0.050
0.400
-
-
-
-
-
-
-
2H
Carbon
0.40 min
1.000
0.040
0.050
0.400
-
-
-
-
-
-
-
2HM
Carbon
0.40 min
1.000
0.040
0.050
0.400
-
-
-
-
-
-
-
3
Type 501
0.10 min
1.000
0.040
0.030
1.000
4.0-6.0
-
0.40-0.65
-
-
-
-
4
carbon, molybdenum
0.40-0.50
0.70-0.90
0.035
0.040
0.15-0.35
-
0.20-0.30
-
-
-
-
6
Type 410
S41000
0.150
1.000
0.040
0.030
1.000
11.5-13.5
-
-
-
-
-
-
6F
Type 416
S416000
0.150
1.250
0.060
0.15min
1.000
12.0-14.0
-
-
-
-
-
6F
Type 416Se
S41623
0.150
1.250
0.060
0.060
1.000
12.0-14.0
-
-
-
-
Selenium, 0.15 min
7, 7M
Type 4140, 4142, 4145, 4140H, 4142H, 4145H
0.37-0.49
0.65-1.10
0.035
0.040
0.15-0.35
0.75-1.2
-
0.15-0.25
-
-
-
-
8
Type 304
S30400
0.080
2.000
0.045
0.030
1.000
18.0-20.0
8.0-11.0
-
-
-
-
8A
Type 304
0.080
2.000
0.045
0.030
1.000
18.0-20.0
8.0-11.0
-
-
-
-
8C
Type 347
S34700
0.080
2.000
0.045
0.030
1.000
17.0-19.0
9.0-12.0
-
10 x Carbon Content, min
-
-
8CA
Type 347
S34700
0.080
2.000
0.045
0.030
1.000
17.0-19.0
9.0-12.0
-
10 x Carbon Content, min
-
-
8CLN, 8CLNA
Type 347LN
S34751
0.0005-0.020
2.000
0.045
0.030
1.000
17.0-19.0
9.0-13.0
-
0.20-0.50, 15 x Carbon Content,min
0.06-0.10
-
8M, 8MA
Type 316
S31600
0.080
2.000
0.045
0.030
1.000
16.0-18.0
10.0-14.0
2.00-3.00
-
-
-
-
8T, 8TA
Type 321
S32100
0.080
2.000
0.045
0.030
1.000
17.0-19.0
9.0-12.0
-
5 x (C+N),Min – 0.70 max
-
0.100
-
8F, 8FA
Type 303
S30300
0.150
2.000
0.200
0.150
1.000
17.0-19.0
8.0-10.0
-
-
-
-
-
8F, 8FA
Type 303 Se
S30323
0.150
2.000
0.200
0.06
1.000
17.0-19.0
8.0-10.0
-
-
-
-
Selenium, 0.15 min
8P, 8PA
Type 305 with restricted carbon
S30500
0.080
2.000
0.045
0.030
1.000
17.0-19.0
11.0-13.0
-
-
-
-
-
8N, 8NA
Type 304N
S30451
0.080
2.000
0.045
0.030
1.000
18.0-20.0
8.0-11.0
-
-
-
0.10-0.16
-
8LN, 8LNA
0.030
2.000
0.045
0.030
1.000
18.0-20.0
8.0-11.0
-
-
-
0.10-0.16
-
8MN, 8MNA
Type 316N
S31651
0.080
2.000
0.045
0.030
1.000
16.0-18.0
10.0-13.0
2.0-3.0
-
-
0.10-0.16
-
8MLN, 8MLNA
Type 316LN
S31653
0.030
2.000
0.045
0.030
1.000
16.0-18.0
10.0-13.0
2.0-3.0
-
-
0.10-0.16
-
8R, 8RA
XM19
S20910
0.060
4.0-6.0
0.045
0.030
1.000
20.5-23.5
11.5-13.5
1.50-3.0
-
0.10-0.30
0.20-0.40
Vanadium,
0.10-0.30
8S, 8SA
S21800
0.100
7.0-9.0
0.060
0.030
3.5-4.5
16.0-18.0
8.0-9.0
-
-
-
0.08-0.18
-
8MLCuN, 8MLCuNA
S31254
S31254
0.020
1.000
0.030
0.010
0.800
19.5-20.5
17.5-18.5
6.0-6.5
-
-
0.18-0.25
Copper
0.50-1.00
9C, 9CA
N08367
N08367
0.030
2.000
0.040
0.030
1.000
20.0-22.0
23.5-25.5
6.0-7.0
-
-
0.18-0.25
Copper
0.75
16
Chromium Molybdenum Vanadium
0.36-0.47
0.45-0.70
0.035
0.040
0.15-0.35
0.80-1.15
0.50-0.65
-
-
-
Vanadium 0.25-0.35
AluminumB 0.015

ASTM A194 Grade 8F Hardness Requirement

Grade & Type
Brinell Hardness
Rockwell Hardness
C Scale
B Scale
8F
126-300
32 max
60 min

ASTM A194 Grade 8F Proof Load (Inch Series)

Nominal Size, inch
Threads per inch
Stress Area inch
Proof Load, lbf
All Types of Grade 8
Heavy Hex
Hex
1/4"
20
0.0316
5570
4770
5/16"
18
0.0524
9170
7860
3/8"
16
0.0774
13560
11620
7/16"
14
0.1063
18600
15940
1/2"
13
0.1419
24830
21280
9/16"
12
0.1820
31850
27300
5/8"
11
0.2260
39550
33900
3/4"
10
0.3340
58450
50100
7/8"
9
0.4620
80850
69300
1"
8
0.606
106000
90900
1 1/8"
8
0.7900
138200
118500
1 1/4"
8
1.0000
175000
150000
1 3/8"
8
1.2330
215800
185000
1 1/2"
8
1.492
261100
223800

ASTM A194 Grade 8F Marking

Grade Type Hot Forged or Cold Punched Nuts Nuts Machined from Bar Stock
8S 8S 8SB