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ASTM A194 Technical Data

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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.

Marking of Nuts^A
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	...
2H^B	2H	2HB	...
2HM^B,C	2HM	2HMB	...
3	3	3B	...
4	4	4B	...
4L^D	4L	4BL	...
6	6	6B	...
6F	6F	6FB	...
7	7	7B	...
7L^D	7L	7BL	...
7M^B,C	7M	7MB	...
7ML^B,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.

Proof Load Using Threaded Mandrel - Inch Series
Nominal Size, in	Threads per Inch	Stress Area in²	Proof Load, Ibf^A
			Grade 1		Grades 2, 2HM, 6, 6F, 7M		Grades 2H, 3, 4, 7, 16		All Types of Grade 8, Grades 9C and 9CA
			Heavy Hex^B	Hex^C	Heavy Hex^D	Hex^E	Heavy Hex^F	Hex^G	Heavy Hex^H	Hex^I
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, kN^A						All Types of Grade 8, and Grades 9C and 9CA
			Grade 1		Grades 2, 2HM, 6, 6F, 7M		Grades 2H, 3, 4, 7, 16		All Types of Grade 8, and Grades 9C and 9CA
			Heavy Hex^B	Hex^C	Heavy Hex^D	Hex^E	Heavy Hex^F	Hex^G	Heavy Hex^H	Hex^I
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.

ASTM 194 HARDNESS PROPERTIES

TABLE 2 Hardness Requirements^A
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
	Brinell Hardness	C Scale	B Scale	Brinell Hardness, min	Rockwell Hardness B Scale, min
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 Requirements^A,B,C,D

Grade Symbol

Material

UNS Number

Carbon, %

Manganese, %

Phosphorus, %

Sulfur^E, %

Silicon, %

Chromium, %

Nickel, %

Molybdenium, %

Titanium, %

Columbium, %

Nitrogen, %

Other Elements, %

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

...

4^G

carbon, molydenum

0.40-0.50

0.70-0.90

0.035

0.04

0.15-0.35

...

0.20-0.30

...

Type 501

0.10 min

1.0

0.04

0.03

1.0

4.0-6.0

...

0.40-0.65

...

Type 410

S41000

0.08-0.15

1.0

0.04

0.03

1.0

11.5-13.5

...

Type 416

S41600

0.15

1.2

0.06

0.15 min

1.0

12.0-14.0

...

Type 416Se

S41623

0.15

1.2

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, 8RA^F

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

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

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

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

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 Aluminum^B

^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.

ASTM A194 Technical Data

ASTM A194 Grades and Markings

Grades and Markings

ASTM A194 Mechanical Properties

MECHANICAL PROPERTIES

ASTM A194 Hardness Requirements

ASTM 194 HARDNESS PROPERTIES

ASTM A194 Chemical Properties

CHEMICAL PROPERTIES