ASTM A194 Grade 8 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 8 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 8 Chemical Components

Grade
Material
UNS
Number
C, %
Mn, %
Ph, %
S, %
Si, %
Cr, %
Ni, %
Mo, %
Ti, %
Cb & Ta, %
N, %
Other Elements, %
8
Type 304
S30400
0.080
2.000
0.045
0.030
1.000
18.0-20.0
8.0-11.0
-
-
-
-

ASTM A194 Grade 8 Hardness Requirement

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

ASTM A194 Grade 8 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 8 Marking

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