SA194

Carbon and alloy steel nuts for bolts for high pressure and high temperature service

SA194

SA194 Chemical Properties

 

Grade 2, 2HM, and 2H 4 7,7M 8,8A 8M, 8MA 16
Material carbon carbon, molybdenum Type 4140/ 4142/ 4145, 4140H, 4142H, 4145H Type 304 Type 316 Chromium Molybdenum Vanadium
UNS
Number
      S30400 S31600  
Carbon % 0.40 min 0.40-0.50 0.37-0.49 0.08 0.08 0.36-0.47
Manganese % 1.00 0.70-0.90 0.65-1.10 2.00 2.00 0.45-0.70
Phosphorus % 0.040 0.035 0.035 0.045 0.045 0.035
Sulfur % 0.050 0.040 0.04 0.030 0.030 0.040
Silicon % 0.40 . .
0 15-0 35
0.15-0.35 1.00 1.00 0.15-0.35
Chromium % ... ... 0 75-1 20
. .
18.0-20.0 16.0-18.0 0.80-1.15
Nickel % ... ... ... 8.0-11.0 10.0-14.0 ...
Molybdenum % ... 0.20-0.30 0.15-0.25 ... 2.00-3.00 0.50-0.65
Titanium % ... ... ... ... . . . ...
Columbium and Tantalum % ... ... ... ... . . . ...
Nitrogen % ... ... ... ... ... ...
Other Elements % ... .. . .. . . .. . .. Vanadium, 0.25-0.35 Aluminum 0.015

 

TABLE 2 Hardness Requirements

  Completed Nuts Sample Nut after Treatment as in 8.1.5

Grade and Type

Brinell
Hardness

Rockwell Hardness

Brinell
Hardness, min

Rockwell
Hardness B Scale, min

C Scale B Scale
2 159 to 352 ... 84 min 159 84
2H Upto 1-1/2 in. or M36, incl 248 to 327 24 to 35 ... 179 89
2H over 1-1/2 in. or M36 212 to 327 35 max 95 min 147 79
2HM and 7M 159 to 235 ... 84 to 99 159 84
3, 4, 7, and 16 248 to 327 24 to 35 ... 201 94
8, 8C, 8CLN, 8M, 8T, 8F, 8P, 8N,
8MN, 8LN, 8MLN,
8MLCuN, and 9C
126 to 300 32 max 60 min ... ...
8A, 8CA, 8CLNA, 8MA, 8TA,
8LNA, 8MLNA,
8FA, 8PA, 8NA, 8MNA,
8MLCuNA, and 9CA
126 to 192 ... 60 to 90 ... ...

A Where ellipses (...) appear in this table there is no requirement.

A194 Mechanical Properties

Specification

Material

Nominal Size, In.

Tempering Temp. °F

Proof Load Stress, ksi

Hardness Rockwell

See Note

Min Max
ASTM A194 Grade 2 Medium Carbon Steel 1/4 - 4 0 150 159 352 1,2,3
ASTM A194 Grade 2H Medium Carbon Steel, Quenched and Tempered 1/4 - 4 850 175 C24 C38 1,2
ASTM A194 Grade 2HM Medium Carbon Steel, Quenched and Tempered 1/4 - 4 1000 150 159 237 1,2,3
ASTM A194 Grade 4 Medium Carbon Alloy Steel, Quenched and Tempered 1/4 - 4 1100 175 C24 C38 1,2
ASTM A194 Grade 7 Medium Carbon Alloy Steel, Quenched and Tempered 1/4 - 4 1100 175 C24 C38 1,2
ASTM A194 Grade 7M Medium Carbon Alloy Steel, Quenched and Tempered 1/4 - 4 1150 150 159 237 1,2,3
ASTM A194 Grade 8 Stainless AISI 304 1/4 - 4 - 80 126 300 4
ASTM A194 Grade 8M Stainless AISI 316 1/4 - 4 - 80 126 300 4
ASTM A194 Grade 16 Chromium MolybdenumVanadium 1/4 - 4          

NOTES: 

1. The markings shown for all grades of A194 nuts are for cold formed and hot forged nuts. When nuts are machined from bar stock, the nut must additionally be marked with the letter 'B'. The letters H and M indicate heat treated nuts.

2. Properties shown are those of coarse and 8-pitch thread heavy hex nuts.

3. Hardness numbers are Brinell Hardness.

4. Nuts that are carbide-solution treated require additional letter A - 8A or 8MA.

5. All nuts shall bear the manufacturer’s identification mark. Nuts shall be legibly marked on one face to indicate the grade and process of the manufacturer. Marking of wrench flats or bearing surfaces is not permitted unless agreed upon between manufacturer and purchaser. Nuts coated with zinc have an asterisk (*) marked after the grade symbol. Nuts coated with cadmium shall have a plus sign (+) marked after the grade symbol.

6. Other less common grades exist, but are not listed here.

Inch Fastener Standards. 7th ed. Cleveland: Industrial Fasteners Institute, 2003. N-80 - N-81.

 

TABLE 3 Proof Load Using Threaded Mandrel - Inch Series

Nominal
Size, in.

Threads
per Inch

Stress Area
in.2

Proof Load, lbf
Grades 2, 2HM, 6, 6F, 7M Grades 2H, 3, 4, 7, 16 All Types of Grade 8, Grades 9C and 9CA
Heavy HexD HexE Heavy HexF Hexg Heavy HexH HexI
1/4 20 0.0316 4770 4300 5570 4770 2540 2380
5/16 18 0.0524 7860 770 9170 7860 4190 3930
3/8 16 0.0774 11620 10460 13560 11620 6200 5810
7/16 14 0.1063 15940 14350 18600 15940 8500 7970
1/2 13 0.1419 21280 19160 24830 21280 11350 10640
3/18 12 0.182 27300 24570 31850 27300 14560 13650
5/8 11 0.226 33900 30510 39550 33900 1880 16950
34 10 0.334 50100 4590 58450 50100 26720 25050
7/8 9 0.462 69300 62370 80850 69300 36960 34650
1 8 0.606 90900 81810 106000 90900 48480 45450
11/8 8 0.790 118500 106700 138200 118500 63200 59250
11/4 8 1.000 150000 1350 175000 150000 80000 75000
13/8 8 1.233 185000 166500 215800 185000 98640 92450
11/2 8 1.492 223800 201400 261100 223800 119360 111900

A See limit for proof load test in 8.2.2.1. The proof load for jam nuts shall be 46 % of the tabulated load.

B Based on proof stress of 130 000 psi.

C Based on proof stress of 120 000 psi.

D Based on proof stress of 150 000 psi.

E Based on proof stress of 135 000 psi.

F Based on proof stress of 175 000 psi.

G Based on proof stress of 150 000 psi.

H Based on proof stress of 80 000 psi.

I Based on proof stress of 75 000 psi.

TABLE 4 Proof Load Using Threaded Mandrel - Metric

NOTE 1-Proof loads are not design loads.

Nominal
Size,
mm

Threads
Pitch

Stress Area
mm2

Proof Load, kNA
Grades 2, 2HM, 6, 6F, 7M Grades 2H, 3, 4,7, 16 All Types of Grade 8, and
Grades 9C and 9CA
Heavy HexD HexE Heavy Hexf Hexg Heavy HexH HexI
M6 1.00 20.10 20.80 18.70 29.20 20.80 11.10 10.40
M8 1.25 36.60 37.90 34.00 44.10 37.90 20.10 18.80
M10 1.50 58.00 60.00 53.90 69.90 60.00 31.90 29.90
M12 1.75 84.30 87.30 78.40 101.60 87.30 46.40 43.40
M14 2.00 115.00 119.00 107.00 138.60 119.00 63.30 59.20
M16 2.00 157.00 162.50 146.00 189.20 162.50 86.40 80.90
M20 2.50 245.00 253.60 227.80 295.20 253.60 134.80 126.20
M22 2.50 303.00 313.60 281.80 365.10 313.60 166.70 156.00
M24 3.00 353.00 365.40 328.30 425.40 365.40 194.20 181.80
M27 3.00 459.00 475.10 426.90 553.40 475.10 252.50 236.40
M30 3.50 561.00 580.60 521.70 676.00 580.60 308.60 288.90
M36 4.00 817.00 845.60 759.80 984.50 845.60 449.40 420.80

A See limit for proof load test in 8.2.2.1. The proof load for jam nuts shall be 46 % of the tabulated load.

B Based on proof stress of 895 MPa.

C Based on proof stress of 825 MPa.

D Based on proof stress of 1035 MPa.

E Based on proof stress of 930 MPa.

F Based on proof stress of 1205 MPa.

G Based on proof stress of 1035 MPa.

H Based on proof stress of 550 MPa.

I Based on proof stress of 515 MPa.

TABLE S1.1 Proof Load Testing of Strain Hardened Nuts Using Threaded Mandrel — Inch Series

Note 1—Proof loads are not design loads.

Nominal
Size, in.
Threads
per in.
Stress Area,
in.2
Grade 8M
(strain hardened)
Grade 8M
(strain hardened)
All Other Types
of Grade 8
(strain hardened)
All Other Types
of Grade 8
(strain hardened)
      Heavy HexB Hexc Heavy HexD HexB
1/4 20 0.0316 3480 3160 3950 3480
5/16 18 0.0523 5760 5240 6550 5760
3/8 16 0.0774 8510 7740 9675 8510
7/16 14 0.1063 11690 10630 13290 11690
1/2 13 0.1419 15610 14190 17740 15610
9/16 12 0.1820 20020 18200 22750 20020
5/8 11 0.2260 24860 22600 28250 24860
3/4 10 0.3340 36740 33400 41750 36740
7/8 9 0.4620 46200 41580 53130 46200
1 8 0.6060 60600 54540 69690 60600
1 1/8 8 0.7900 75050 67150 82950 75050
1 1/4 8 1.0000 95000 85000 105000 95000
1 3/8 8 1.2330 110970 98640 123300 110970
1 1/2 8 1.4920 134280 119360 149200 134280

A See limit for proof load test in 8.2.2.1. The proof load for jam nuts shall be 46 % of the tabulated load.

B Based on proof stress of 130 000 psi.

C Based on proof stress of 120 000 psi.

D Based on proof stress of 150 000 psi.

E Based on proof stress of 135 000 psi.

F Based on proof stress of 175 000 psi.

G Based on proof stress of 150 000 psi.

H Based on proof stress of 80 000 psi.

I Based on proof stress of 75 000 psi.

 

TABLE 4 Proof Load Using Threaded Mandrel - Metric

NOTE 1-Proof loads are not design loads.

Nominal
Size,
mm

Threads
Pitch

Stress Area
mm2

Proof Load, kNA
Grades 2, 2HM, 6, 6F, 7M Grades 2H, 3, 4,7, 16 All Types of Grade 8, and
Grades 9C and 9CA
Heavy HexD HexE Heavy Hexf Hexg Heavy HexH HexI
M6 1.00 20.10 20.80 18.70 29.20 20.80 11.10 10.40
M8 1.25 36.60 37.90 34.00 44.10 37.90 20.10 18.80
M10 1.50 58.00 60.00 53.90 69.90 60.00 31.90 29.90
M12 1.75 84.30 87.30 78.40 101.60 87.30 46.40 43.40
M14 2.00 115.00 119.00 107.00 138.60 119.00 63.30 59.20
M16 2.00 157.00 162.50 146.00 189.20 162.50 86.40 80.90
M20 2.50 245.00 253.60 227.80 295.20 253.60 134.80 126.20
M22 2.50 303.00 313.60 281.80 365.10 313.60 166.70 156.00
M24 3.00 353.00 365.40 328.30 425.40 365.40 194.20 181.80
M27 3.00 459.00 475.10 426.90 553.40 475.10 252.50 236.40
M30 3.50 561.00 580.60 521.70 676.00 580.60 308.60 288.90
M36 4.00 817.00 845.60 759.80 984.50 845.60 449.40 420.80

A See limit for proof load test in 8.2.2.1. The proof load for jam nuts shall be 46 % of the tabulated load.

B Based on proof stress of 895 MPa.

C Based on proof stress of 825 MPa.

D Based on proof stress of 1035 MPa.

E Based on proof stress of 930 MPa.

F Based on proof stress of 1205 MPa.

G Based on proof stress of 1035 MPa.

H Based on proof stress of 550 MPa.

I Based on proof stress of 515 MPa.

 

TABLE S1.1 Proof Load Testing of Strain Hardened Nuts Using Threaded Mandrel — Inch Series

Note 1—Proof loads are not design loads.

Nominal
Size, in.
Threads
per in.
Stress Area,
in.2
Grade 8M
(strain hardened)
Grade 8M
(strain hardened)
All Other Types
of Grade 8
(strain hardened)
All Other Types
of Grade 8
(strain hardened)
      Heavy HexB Hexc Heavy HexD HexB
1/4 20 0.0316 3480 3160 3950 3480
5/16 18 0.0523 5760 5240 6550 5760
3/8 16 0.0774 8510 7740 9675 8510
7/16 14 0.1063 11690 10630 13290 11690
1/2 13 0.1419 15610 14190 17740 15610
9/16 12 0.1820 20020 18200 22750 20020
5/8 11 0.2260 24860 22600 28250 24860
3/4 10 0.3340 36740 33400 41750 36740
7/8 9 0.4620 46200 41580 53130 46200
1 8 0.6060 60600 54540 69690 60600
1 1/8 8 0.7900 75050 67150 82950 75050
1 1/4 8 1.0000 95000 85000 105000 95000
1 3/8 8 1.2330 110970 98640 123300 110970
1 1/2 8 1.4920 134280 119360 149200 134280

A The proof load for jam nuts shall be 46 % of the tabulated value.

B Based on proof stress of 110 000 psi up to 3/4 in.; 100 000 psi 7/8 to 1 in.; 95 000 psi 11/8 to 11/4 in.; 90 000 psi 1% to 11/2 in.

C Based on proof stress of 100 000 psi up to 3/4 in.; 90 000 psi 7/8 to 1 in.; 85 000 psi 1% to 11/4 in.; 80 000 psi 1% to 11/2 in.

D Based on proof stress of 125 000 psi up to 3/4 in.; 115 000 psi 7/8 to 1 in.; 105 000 psi 11/s to 11/4 in.; 100 000 psi 13/s to 11/2 in.

 

TABLE S1.2 Proof Load Testing of Strain Hardened Nuts Using Threaded Mandrel - Metric

Note 1-Proof loads are not design loads.

Nominal
Size, mm
Thread
Pitch
Stress Area,
mm2
Grade 8M
(strain hardened)
Grade 8M
(strain hardened)
All Other Types
of Grade 8
(strain hardened)
All Other Types
of Grade 8
(strain hardened)
      Heavy HexB Hexc Heavy HexD HexB
M6 1 20.1 15.3 13.9 17.3 15.3
M8 1.25 36.6 27.8 25.3 31.3 27.8
M10 1.5 58 44.1 40 49.9 44.1
M12 1.75 84.3 64.1 58.2 72.5 64.1
M14 2 115 87.4 79.4 98.9 87.4
M16 2 157 119.3 108.3 135 119.3
M20 2.5 245 186.2 169 210.9 186.2
M22 2.5 303 209 187.9 240.9 209
M24 3 353 243.5 218.9 280.6 243.5
M27 3 459 300.6 268.5 332.7 300.6
M30 3.5 561 367.5 328.2 406.7 367.5
M36 4 817 506.5 449.4 563.7 506.5

A The proof load for jam nuts shall be 46 % of the tabulated value.

B Based on proof stress of 760 MPa up to M20 mm; 690 MPa M22 to M24 mm; 655 MPa M27 to M30; and 620 MPa for M36.

C Based on proof stress of 690 MPa up to M20 mm; 620 MPa M22 to M24 mm; 585 MPa M27 to M30; and 550 MPa for M36.

D Based on proof stress of 860 MPa up to M20 mm; 795 MPa M22 to M24 mm; 725 MPa M27 to M30 mm; and 690 MPa for M36.

 

TABLE S4.1 Proof Load for Large Heavy Hex Nuts - Inch

Nominal
Size, in.

Threads
per in.

Stress Area,
in. 2

Proof Load, lbf
Grades 2, 2HM, 6, 6F, 7M
Heavy Hex
Grades 2H, 3, 4, 7, 16
Heavy Hex
1 5/8 8 1.78 267000 311500
1 3/4 8 2.08 312000 3M 000
1 7/8 8 2.41 361500 421800
2 8 2.77 415500 484800
2 1/4 8 3.56 534000 623000
2 1/2 8 4.44 666000 777000
2 3/4 8 5.43 814500 950250

A ASME B18.2.2 in the size range over 11/2 in. provides dimensions only for heavy hex nuts. Refer to 8.3.1.

B Proof loads for nuts of larger dimensions or other thread series may be calculated by multiplying the thread stress area times the proof stress in the notes to Table 3 or Table S1.1. The proof load for jam nuts shall be 46 % of the tabulated load.

 

TABLE S4.1 Proof Load for Large Heavy Hex Nuts - METRIC

Nominal Size,
mm

Thread Pitch

Stress Area,
mm 2

Proof Load, kN
Grades 2, 2HM, 6, 6F, 7M
Heavy Hex
Grades 2H, 3, 4, 7, 16
Heavy Hex
M42 4.50 1120 1159.20 1349.60
M48 5.00 1470 1521.40 1771.40
M56 5.50 2030 2101.00 2446.20
M64 6.00 2680 2773.80 3229.40
M72 6.00 3460 3581.10 4169.30

A ASME B 18.2.4.6M in the size range over M36 provides dimensions only for heavy hex nuts. Refer to 7.3.1.

B Proof loads for nuts of larger dimensions or other thread series may be calculated by multiplying the thread stress area times the proof stress in the notes to Table 4 or Table S1.2. The proof load for jam nuts shall be 46 % of the tabulated load.