ASTM A194 Grade 7MG Heavy Hex Nuts

Reliable alloy steel nuts designed for demanding bolting environments.

ASTM A194/A194M Grade 7MG Nuts are heavy-duty industrial fasteners used in piping systems, refinery equipment, and mechanical assemblies requiring dependable strength. These alloy steel nuts provide durability and secure performance under demanding operating conditions. Grade 7MG nuts are widely used alongside ASTM A193/A193M bolting materials and ASTM A320/A320M fasteners for industrial projects involving temperature variation. ASTM A563M and ASTM F2437/F2437M specifications further support their use in engineered fastening systems and structural installations.

ASTM A194/A194M Gr 7MG Chemical Requirements

Grade

Description
and
UNS Designation

S^E

ASTM A194/A194M 7M^G

Cr - Mo^G

0.38-0.48

0.75-1.0

0.035

0.04

0.15-0.35

0.80-1.10

0.15-0.25

(A) Total aluminum, soluble and insoluble.
(B) Maximum, unless minimum or range is indicated.
(C) Where ellipses (...) appear in this table there is no requirement.

ASTM A194/A194M Gr 7MG Proof Load Requirements (Inch Series)

Nominal Size, in.

Threads per Inch

Stress Area in.²

Proof Load, lbf ^A

Grades 2, 2HM, 6, 6F, 7M

Heavy Hex^D

Hex^E

¹/₄

0.0316

4 770

4 300

⁵/₁₆

0.0524

7 860

7 070

³/₈

0.0774

11 620

10 460

⁷/₁₆

0.1063

15 940

14 350

¹/₂

0.1419

21 280

19 160

⁹/₁₆

0.182

27 300

24 570

⁵/₈

0.226

33 900

30 510

³/₄

0.334

50 100

45 090

⁷/₈

0.462

69 300

62 370

0.606

90 900

81 810

1¹/₈

0.790

118 500

106 700

1¹/₄

1.000

150 000

135 000

1³/₈

1.233

185 000

166 500

1¹/₂

1.492

223 800

201 400

(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.

ASTM A194/A194M Gr 7MG Proof Load Requirements (Metric Series)

Nominal Size, mm

Threads Pitch

Stress Area mm²

Proof Load, kN^A

Grades 2, 2HM, 6, 6F, 7M

Heavy Hex^D

Hex^E

1.0

20.1

20.8

18.7

1.25

36.6

37.9

34.0

M10

1.50

58.0

60.0

53.9

M12

1.75

84.3

87.3

78.4

M14

2.0

115.0

119.0

107.0

M16

2.0

157.0

162.5

146.0

M20

2.5

245.0

253.6

227.8

M22

2.5

303.0

313.6

281.8

M24

3.0

353.0

365.4

328.3

M27

3.0

459.0

475.1

426.9

M30

3.5

561.0

580.6

521.7

M36

4.0

817.0

845.6

759.8

(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.

Related A194 Grades & References

Grade 7MG is a sour-service Cr-Mo alloy A194 nut variant (NACE MR0175 hardness-controlled). For standard non-sour Cr-Mo see Grade 7G. Carbon-steel sour equivalent: Grade 2HM. For stainless sour service: Grade 8M or Grade 8MN. Dimensions: ASME B18.2.2 heavy hex. Full specification: ASTM A194 PDF. A194 hub.

International Equivalents

Standard	Region	Notes
ASTM A194-7M (parent)	USA	Standard A194 7M sour-service grade
API 20E BSL-2	API	Sour-service bolting specification
NACE MR0175 / ISO 15156	Global	Sour-service materials requirement
BS EN 10269 (sour)	EU	European sour-service bolting

Specifications

Surface Treatments

Xylan 1070 / 1014 / 1400 / 1424

Xylar 2 / 101

Geomet 321 / 500 / 720

SermaGard 1105 / 1280

Dacromet 320 / 500

TakeCoat 1000 Ceramic

Delta Tone/Seal

Magnigard

MolyKote

Sherardized

Zinc-Cobalt (ASTM B840)

Zinc-Nickel (ASTM B841)

Certifications

ISO 9001 - 2015 Certified
PED 2014/68/EC
NACE MR0175/ISO 15156-2
NORSOK M-650
DFAR
MERKBLATT AD 2000 W2/W7/W10