ASTM A194 Grade 8MN 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 8MN Nut Grades

Grade Tensile Class Raw Material
B5 4-6% Chromium Ferritic Steel

ASTM A194 Grade 8MN Chemical Components

Grade Material UNS
Number
C, % Mn, % Ph, % S, % Si, % Cr, % Ni, % Mo, % Ti, % Cb & Ta, % N, % Other Elements, %
8MN
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
-

ASTM A194 Grade 8MN Hardness Requirement

Grade & Type Brinell Hardness Rockwell Hardness
C Scale B Scale
8, 8C, 8M, 8T, 8F, 8MLCuN 126-300 32 max 60 min
8A, 8CA, 8MA, 8TA, 8MLCuNA 126-192 - 60 – 90

ASTM A194 Grade 8MN 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 8MN Marking

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