Grade 16

ASTM A194 Grade 16 Specification for high tensile nuts and other internally threaded fasteners, made from heat treated chromium-molybdenum-vanadium steel. ASTM A194 Grade 16 is a standard material specification for high tensile nuts and other internally threaded fasteners, made from chromium-molybdenum-vanadium steel. Grade 16 nuts can be produced by means of hot forging, cold forging and followed by quenched-tempering or machining from heat treated bar stock. ASTM A194 specification covers requirements for chemical composition, heat treatment, hardness, proof load, etc., for Grade 16 nuts.

Chemical Composition

Element	Alloy Steel
	Chromium Molybdenum Vanadium Steel
	CompositionA, %
Carbon	0.36 - 0.47
Manganese	0.45 - 0.70
Phosphorus	0.035 max
Sulfur	0.040 max
Silicon	0.15 - 0.35
Chromium	0.80 - 1.15
Molybdenum	0.50 - 0.65
Vanadium	0.25 - 0.35
Aluminum	0.015 maxB

A: The intentional addition of Bi, Se, Te, and Pb is not permitted.
B: Total aluminum, soluble and insoluble.

Hardness

Grade Type	Completed Nuts			Sample Nut After Heat Treatment
	Brinell Hardness, BHN, min	Rockwell Hardness		Brinell Hardness, BHN, min	Rockwell Hardness, HRB, min
		HRC, min	HRB, min
16	248 - 327	24 - 35	...	201	94

Heat Treatment: Quenched & Tempered at minimum temperature 1200º F [650º C].

Proof Load

Nominal Size, Inch.	Threads Per Inch	Proof Load, lbf
		Heavy HexA	HexB
1/4	20	5 570	4 770
5/16	18	9 170	7 860
3/8	16	13 560	11 620
7/16	14	18 600	15 940
1/2	13	24 830	21 280
9/16	12	31 850	27 300
5/8	11	39 550	33 900
3/4	10	58 450	50 100
7/8	09	80 850	69 300
01	08	106 000	90 900
1-1/8	08	138 200	118 500
1-1/4	08	175 000	150 000
1-3/8	08	215 800	185 000
1-1/2	08	261 100	223 800

A: Based on proof stress of 175 000 psi.
B: Based on proof stress of 150 000 psi.

Nuts

Commonly Produced Grade 16 Nuts
Hex Nuts	Heavy Hex Nuts	Jam Nuts	Heavy Hex Jam Nuts	Castle Nuts
Coupling Nuts	Square Nuts	Thin Square Nuts	All Metal Lock Nuts	Dome Nuts