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ASTM A194 TECHNICAL DATA

 

Order A194 Grade 2H Hex Nuts Order A194 Grade 2HM Hex Nuts Order A194 Grade7 Hex Nuts Order A194 Grade 8 Hex Nuts Order A194 Grade 8M Hex Nuts

ASTM A194 is a specification that covers a variety of carbon, alloy, and stainless steel nuts intended for use in high-pressure and high-temperature service. The specification covers both inch and metric nuts. The nuts are intended for use with bolts and other fasteners that conform to ASTM A193, ASTM A320, and other specifications. The specification includes several grades of nuts, each with different chemical and mechanical properties, to suit different applications.

Technical Data: ASTM A194 Grades and Markings Mechanical Properties ASTM A194 Materials & Chemical Properties

 

ASTM A194 Grades and Markings

The ASTM A194 specification governs mechanical and material requirements for carbon steel, alloy steel, and stainless steel nuts in the size range of 1/4 to 4 inches and metric M6 through M100 nominal. The specification also covers austensic steel nuts up to ¼ inch and M6 nominal and above. 

Grades and Markings

Marking of NutsA
Grade and Type Nuts Hot Forged or Cold Punched Nuts Machined from Bar Stock Nuts Manufactured in Accordance with 6.6
1 1 1B ...
2 2 2B ...
2HB 2H 2HB ...
2HMB,C 2HM 2HMB ...
3 3 3B ...
4 4 4B ...
4LD 4L 4BL ...
6 6 6B ...
6F 6F 6FB ...
7 7 7B ...
7LD 7L 7BL ...
7MB,C 7M 7MB ...
7MLB,D 7ML 7MLB ...
8 8 8B 8A
8C 8C 8CB 8CA
8CLN 8CLN 8CLNB 8CLNA
8M 8M 8MB 8MA
8T 8T 8TB 8TA
8F 8F 8FB 8FA
8P 8P 8PB 8PA
8N 8N 8NB 8NA
8MN 8MN 8MNB 8MNA
8R 8R 8RB 8RA
8S 8S 8SB 8SA
8LN 8LN 8LNB 8LNA
8MLN 8MLN 8MLNB 8MLNA
8MLCuN 8MLCuN 8MLCuNB 8MLCuNA
8ML4CuN 8ML4CuN 8ML4CuNB 8ML4CuNA
9C 9C 9CB 9CA
16 16 16B  

 

AWhere ellipses (...) appear in this table there is no requirement.
BThe letters H and M indicate heat-treated nuts (see Section 6).
CAn underline as a marking requirement for grades 2HM and 7M has been removed but is permitted.
DSee Supplementary Requirement S3.

ASTM A194 Mechanical Properties

The mechanical properties requirements for nuts with an ASTM A194 specification govern the hardness required for nuts depending on their grade and type. The nuts must also be able to withstand proof loads determined by their nominal sizes.

MECHANICAL PROPERTIES

Proof Load Using Threaded Mandrel - Inch Series
Nominal Size, in Threads per Inch Stress Area in2 Proof Load, IbfA
Grade 1 Grades 2, 2HM, 6, 6F, 7M Grades 2H, 3, 4, 7, 16 All Types of Grade 8, Grades 9C and 9CA
Heavy HexB HexC Heavy HexD HexE Heavy HexF HexG Heavy HexH HexI
1/4 20 0.0316 4 130 3 820 4 770 4 300 5 570 4 770 2 540 2 380
5/16 18 0.0524 6 810 6 290 7 860 7 070 9 170 7 860 4 190 3 930
3/8 16 0.0774 10 080 9 300 11 620 10 460 13 560 11 620 6 200 5 810
 7/16 14 0.1063 13 820 12 760 15 940 14 350 18 600 15 940 8 500 7 970
 1/2 13 0.1419 18 450 17 030 21 280 19 160 24 830 21 280 11 350 10 640
 9/16 12 0.182 23 660 21 840 27 300 24 570 31 850 27 300 14 560 13 650
 5/8 11 0.226 29 380 27 120 33 900 30 510 39 550 33 900 18 080 16 950
 3/4 10 0.334 43 420 40 080 50 100 45 090 58 450 50 100 26 720 25 050
 7/8 9 0.462 60 060 55 440 69 300 62 370 80 850 69 300 36 960 34 650
1 8 0.606 78 780 72 720 90 900 81 810 106 000 90 900 48 480 45 450
1 1/8 8 0.790 102 700 94 800 118 500 106 700 138 200 118 500 63 200 59 250
1 1/4 8 1.000 130 000 120 000 150 000 135 000 175 000 150 000 80 000 75 000
1 3/8 8 1.233 160 200 148 000 185 000 166 500 215 800 185 000 98 640 92 450
1 1/2 8 1.492 194 000 170 040 223 800 201 400 261 100 223 800 119 360 111 900
Proof Load Using Threaded Mandrel - Metric
Nominal Size, mm Threads Pitch Stress Area mm2 Proof Load, kNA All Types of Grade 8, and Grades 9C and 9CA
Grade 1 Grades 2, 2HM, 6, 6F, 7M Grades 2H, 3, 4, 7, 16
Heavy HexB HexC Heavy HexD HexE Heavy HexF HexG Heavy HexH HexI
M6 1.00 20.1 18.0 16.6 20.8 18.7 29.2 20.8 11.1 10.4
M8 1.25 36.6 32.8 30.2 37.9 34.0 44.1 37.9 20.1 18.8
M10 1.50 58.0 51.9 47.9 60.0 53.9 69.9 60.0 31.9 29.9
M12 1.75 84.3 75.5 69.5 87.3 78.4 101.6 87.3 46.4 43.4
M14 2.00 115.0 102.9 94.9 119.0 107.0 138.6 119.0 63.3 59.2
M16 2.00 157.0 140.5 129.5 162.5 146.0 189.2 162.5 86.4 80.9
M20 2.50 245.0 219.2 202.1 253.6 227.8 295.2 253.6 134.8 126.2
M22 2.50 303.0 271.2 249.9 313.6 281.8 365.1 313.6 166.7 156.0
M24 3.00 353.0 315.9 291.2 365.4 328.3 425.4 365.4 194.2 181.8
M27 3.00 459.0 411.0 378.7 475.1 426.9 553.4 475.1 252.5 236.4
M30 3.50 561.0 502.1 462.8 580.6 521.7 676.0 580.6 308.6 288.9
M36 4.00 817.0 731.2 674.0 845.6 759.8 984.5 845.6 449.4 420.8

ASee limit for proof load test in 8.2.2.1. The proof load for jam nuts shall be 46 % of the tabulated load.
BBased on proof stress of 895 MPa.
CBased on proof stress of 825 MPa.
DBased on proof stress of 1035 MPa.
EBased on proof stress of 930 MPa.
FBased on proof stress of 1205 MPa.
GBased on proof stress of 1035 MPa.
HBased on proof stress of 550 MPa.
IBased on proof stress of 515 MPa.

 

ASTM A194 Hardness Requirements

The dimensional requirements for nuts with an ASTM A194 specification determines that the nuts should be hexagonal and conform to the dimensions for hex or heavy hex series dimensions outlined by ASME B 18.2.2, ASME B 18.2.4.6M and ISO 4033.

TABLE 2 Hardness RequirementsA
Grade and Type Completed Nuts Sample Nut after Treatment as in 8.1.5
Brinell Hardness Rockwell Hardness Brinell Hardness, min Rockwell Hardness B Scale, min
C Scale B Scale
1 121 min ... 70 min 121 70
2 159 to 352 ... 84 min 159 84
2H to 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
6 and 6F 228 to 271 20 to 28 … … …
8, 8C, 8CLN, 8M, 8T, 8F, 8P,
8N8MN, 8LN, 8MLN,
8MLCuN, 8ML4CuN,
and 9C 		228 to 300 32 max 60 min … …
8A, 8CA, 8CLNA, 8MA, 8TA,
8FA, 8PA, 8NA, 8MNA,
8LNA, 8MLNA,
8MLCuNA,
8ML4CuNA,
and 9CA 		126 to 192 … 60 to 90 … …
8R, 8RA, 8S, and 8SA 183 to 271 25 max 88 min … …

 

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

ASTM A194 Chemical Properties

The steel used to manufacture nuts that fall into the ASTM A194 specification must conform to chemical composition requirements that specify the permitted percentages of elemental metals within the steel used for the nuts. 

CHEMICAL PROPERTIES

Chemical RequirementsA,B,C,D
Grade Symbol Material UNS Number Carbon, % Manganese, % Phosphorus, % SulfurE, % Silicon, % Chromium, % Nickel, % Molybdenium, % Titanium, % Columbium, % Nitrogen, % Other Elements, %
1 carbon 0.15 min 1.0 0.04 0.05 0.4 ... ... ... ... ... ... ...
2, 2HM, and 2H carbon 0.40 min 1.0 0.04 0.05 0.4 ... ... ... ... ... ... ...
4G carbon, molydenum 0.40-0.50 0.70-0.90 0.035 0.04 0.15-0.35 ... ... 0.20-0.30 ... ... ... ...
3 Type 501 0.10 min 1.0 0.04 0.03 1.0 4.0-6.0 ... 0.40-0.65 ... ... ... ...
6 Type 410 S41000 0.08-0.15 1.0 0.04 0.03 1.0 11.5-13.5 ... ... ... ... ... ...
6F Type 416 S41600 0.15 1.2 0.06 0.15 min 1.0 12.0-14.0 ... ... ... ... ... ...
6F Type 416Se S41623 0.15 1.2 0.06 0.06 1.0 12.0-14.0 ... ... ... ... ... Selenium, 0.15 min
7, 7M Type 4140/4142/4145,4140H,4142H, 4145H 0.38-0.48 0.75-1.0 0.035 0.04 0.15-0.35 0.80-1.10 ... 0.15-0.25 ... ... ... ...
8, 8A Type 304 S30400 0.08 2.0 0.045 0.03 1.0 18.0-20.0 8.0-11.0 ... ... ... ... ...
8C, 8CA Type 347 S34700 0.08 2.0 0.045 0.03 1.0 17.0-19.0 9.0-12.0 ... ... 10 x carbon content, min 1.10 ... ...
8CLN, 8CLNA Type 347LN S34751 0.005-0.02 2.0 0.045 0.03 1.0 17.0-19.0 9.0-13.0 ... ... 0.20-0.50, 15x carbon content, min 0.06-0.10 ...
8M, 8MA Type 316 S31600 0.08 2.0 0.045 0.03 1.0 16.0-18.0 10.0-14.0 2.00-3.00 ... ... ... ...
8T, 8TA Type 321 S32100 0.08 2.0 0.045 0.03 1.0 17.0-19.0 9.0-12.0 ... 5 x (C+N) min-0.7 max ... 0.10 ...
8F, 8FA Type 303 S30300 0.15 2.0 0.2 0.15 min 1.0 17.0-19.0 8.0-10.0 ... ... ... ... ...
8F, 8FA Type 303Se S30323 0.15 2.0 0.2 0.06 1.0 17.0-19.0 8.0-10.0 ... ... ... ... Selenium, 0.15 min
8P, 8PA Type 305 S30500 0.12 2.0 0.045 0.03 1.0 17.0-19.0 11.0-13.0 ... ... ... ... ...
8N, 8NA Type 304N S30451 0.08 2.0 0.045 0.03 1.0 18.0-20.0 8.0-11.0 ... ... ... 0.10-0.16 ...
8LN, 8LNA Type 304LN S30453 0.03 2.0 0.045 0.03 1.0 18.0-20.0 8.0-11.0 ... ... ... 0.10-0.16 ...
8MN, 8MNA Type 316N S31651 0.08 2.0 0.045 0.03 1.0 16.0-18.0 10.0-13.0 2.00-3.00 ... ... 0.10-0.16 ...
8MLN, 8MLNA Type 316LN S31653 0.03 2.0 0.045 0.03 1.0 16.0-18.0 10.0-13.0 2.00-3.00 ... ... 0.10-0.16 ...
 8R, 8RAF XM19 S20910 0.06 4.0-6.0 0.045 0.03 1.0 20.5-23.5 11.5-13.5 1.50-3.00 ... 0.10-0.30 0.20-0.40 Vnadium, 0.10-0.30
8S, 8Sa S21800 0.1 7.0-9.0 0.06 0.03 3.5-4.5 16.0-18.0 8.0-9.0 ... ... ... 0.08-0.18
8MLCuN, 8MLCuNA S31254 S31254 0.02 1.0 0.03 0.01 0.8 19.5-20.5 17.5-18.5 6.0-6.5 ... ... 0.18-0.22 Copper, 0.50-1.00
B8ML4CuN S31730 S31730 0.03 2.0 0.04 0.01 1.0 17.0-19.0 15.0-16.5 3.0-4.0 ... ... 0.045 Copper 4.0-5.0
9C, 9CA N08367 N08367 0.03 2.0 0.04 0.03 1.0 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 0.04 0.15-0.35 0.80-1.15 ... 0.50-0.65 ... ... ... Vanadium, 0.25-0.35 AluminumB

AThe intentional addition of Bi, Se, Te, and Pb is not permitted except for Grades 6F, 8F, and 8FA, in which Se is specified and required.
BTotal aluminum, soluble and insoluble.
CMaximum, unless minimum or range is indicated.
DWhere ellipses ({) appear in this table there is no requirement and the element need not be determined or reported.
EBecause of the degree to which sulfur segregates, product analysis for sulfur over 0.060 % max is not technologically appropriate.
FAs described in Specification A276. GGrade 4 is expected to be withdrawn within approximately 2 years. Grade 7 is an acceptable substitute for Grade 4. See 7.2.