ASTM A194-2H Heavy Hex Nuts

ASTM A194-2H

Quenched & tempered carbon steel heavy hex nuts

The ASTM A194 specification covers carbon, alloy and stainless steel nuts intended for use in high-pressure and/or high-temperature service. Unless otherwise specified, the American National Standard Heavy Hex Series (ANSI B 18.2.2) shall be used.

Nuts up to and including 1 inch nominal size shall be UNC Series Class 2B fit. Nuts over 1 inch nominal size shall be either UNC Series Class 2B fit or 8 UN Series Class 2B fit. High strength ASTM A194-2H nuts are common in the marketplace and are often substituted for ASTM A563-DH nuts due to the limited availability of DH nuts in certain diameters and finishes.

Boulons Plus offer these nuts in plain steel, mechanically galvanized, hot dip galvanized (dyed and lubricated) and Weathering Steel (Type 3) finishes.

Specifications

Dimensions & Markings

Nominal Size	F			C		H			Weight Per 100 nuts
	Width Across Flats			Width Across Corners		Thickness
	Basic	Max	Min	Max	Min	Basic	Max	Min
1/4	1/2	0.500	0.488	0.577	0.556	15/64	0.250	0.218	1.00
5/16	9/16	0.562	0.546	0.650	0.622	16/64	0.341	0.280	2.00
3/8	11/16	0.688	0.669	0.794	0.763	23/64	0.377	0.341	3.00
1/2	7/8	0.875	0.850	1.010	0.969	31/64	0.504	0.464	7.00
5/8	1 1/16	1.062	1.031	1.227	1.175	39/64	0.631	0.587	12.00
3/4	1 1/4	1.250	1.212	1.443	1.382	47/64	0.758	0.710	20.00
7/8	1 7/16	1.438	1.394	1.660	1.589	54/64	0.885	0.833	30.00
1	1 5/8	1.625	1.575	1.876	1.796	63/64	1.012	0.956	43.00
1 1/8	1 13/16	1.812	1.756	2.093	2.002	1 7/64	1.139	1.079	59.00
1 1/4	2	2.000	1.938	2.309	2.209	1 7/32	1.251	1.187	79.00
1 3/8	2 3/16	2.188	2.119	2.526	2.416	1 11/32	1.378	1.310	102.00
1 1/2	2 3/8	2.375	2.300	2.742	2.622	1 15/32	1.505	1.433	131.00
1 5/8	2 9/16	2.562	2.481	2.959	2.828	1 19/32	1.632	1.556	162.00
1 3/4	2 3/4	2.750	2.662	3.175	3.035	1 23/32	1.759	1.679	204.00
1 7/8	2 15/16	2.938	2.844	3.392	3.242	1 27/32	1.886	1.802	241.00
2	3 1/8	3.125	3.025	3.608	3.449	1 31/32	2.013	1.925	299.00
2 1/4	3 1/2	3.500	3.388	4.041	3.862	2 13/64	2.251	2.155	419.00
2 1/2	3 7/8	3.875	3.750	4.474	4.275	2 29/64	2.505	2.401	564.00
2 3/4	4 1/4	4.250	4.112	4.907	4.688	2 45/64	2.759	2.647	738.00
3	4 5/8	4.625	4.475	5.340	5.102	2 61/64	3.013	2.893	950.00
3 1/4	5	5.00	4.838	5.774	5.514	3 3/16	3.252	3.124	1194.00
3 1/2	5 3/8	5.375	5.200	6.207	5.928	3 7/16	3.506	3.370	1526.00
3 3/4	5 3/4	5.750	5.562	6.640	6.341	3 11/16	3.760	3.616	1812.00
4	6 1/8	6.125	5.925	7.073	6.755	3 15/16	4.014	3.862	2180.00

This table is inspired by Table 3 from ASME B18.2.6 standard

Product Marking

Manufacturer ID and 2H (or 2HB when manufactured from bar stock)

SOURCE: The informations above are from the ASTM A194 Standard that you can purchase on the ASTM Website.

A194-2H Chemical Properties

Mechanical Properties

ASTM A563-DH & A194-2H Mechanical Requirements
Grade	Style	Nominal nut size, in.	Proof Load stress, Ksi^A		Hardness
			Plain^B	Galvanized^B	Brinell		Rockwell
					Min	Max	Min	Max
A563 DH^D/DH3/A194-2H	Heavy Hex Nut	1/4 to 4	175	150	248	352	C24	C38

***This table apply for UNC, 8UN, 6UN, and Coarse Pitch Threads***

^A To determine nut proof load in pounds, multiply the appropriate nut proof load stress by the tensile stress area of the thread. Stress areas for UNC, UNF, and 8 UN thread series are given in Table 4.

^B Non-zinc-coated nuts are nuts intended for use with externally threaded fasteners which have a plain (nonplated or noncoated) finish or have a plating or coating of insufficient thickness to necessitate overtapping the nut thread to provide assemblability. Zinc-coated nuts are nuts intended for use with externally threaded fasteners which are hot-dip zinc-coated, mechanically zinc-coated, or have a plating or coating of sufficient thickness to necessitate overtapping the nut thread to provide assemblability.

^D Nuts made in accordance with the requirements of Specification A194/A194M, Grade 2H, and marked with its grade symbol are an acceptable equivalent for Grade DH nuts. When A194 zinc-coated inch series nuts are supplied, the zinc coating, overtapping, lubrication and rotational capacity testing shall be in accordance with Specification A563.

Source: The table above is inspired by Table 3 from the ASTM A563 Standard that you can purchase on the ASTM Website

Tensile

Nominal Size Threads TPI	UNC
	Tensile Stress
	Area,^A A_s in.²
1/4-20	0.0318
5/16-18	0.0524
3/8-16	0.0775
7/16-14	0.1063
1/2-13	0.1419
9/16-12	0.182
5/8-11	0.226
3/4-10	0.334
7/8-9	0.462
1-8	0.606
1 1/8-7	0.763
1 1/4-7	0.969
1 3/8-6	1.155
1 1/2-6	1.405
1 3/4-5	1.90
2-4 1/2	2.50
2 1/4-4 1/2	3.25
2 1/2-4	4.00
2 3/4-4	4.93
3-4	5.97
3 1/4-4	7.10
3 1/2-4	8.33
3 3/4-4	9.66
4-4	11.08

^AA_s The Area is calculated as follows:

Where:
A_s = Stress Area, in²
D = Nominal size, in., and
n = Threads per inch

Buy the ASTM A194 Standard

Chemical Requirements For ASTM A194-2H (Type 1)
Element	Composition %
Element	Heat Anaysis
Carbon	0.40 Max
Manganese	1.00 Max
Phosphorus, Max	0.040
Sulfur, Max	0.050
Silicon	0.40 Max
Chromium	***
Nickel	***
Molybdenum	***

ASTM A194-2H

Quenched & tempered carbon steel heavy hex nuts

Specifications

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