M18 Grade 4.6 Torque Specification

Torque Values by Surface Condition

Stress area: 192.47 mm² · Proof load: 43,306 N · Clamp load (75%): 32,479 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	116.9	86.2	1034.7	1192.1
Oiled	0.15	87.7	64.7	776.2	894.3
Zinc Plated	0.18	105.2	77.6	931.1	1072.7
Waxed	0.1	58.5	43.1	517.8	596.5
MoS₂	0.12	70.2	51.8	621.3	715.8
Galvanized	0.25	146.2	107.8	1294.0	1490.8

Stress area: 216.23 mm² · Proof load: 48,652 N · Clamp load (75%): 36,489 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	131.4	96.9	1163.0	1339.9
Oiled	0.15	98.5	72.6	871.8	1004.4
Zinc Plated	0.18	118.2	87.2	1046.2	1205.3
Waxed	0.1	65.7	48.5	581.5	670.0
MoS₂	0.12	78.8	58.1	697.4	803.5
Galvanized	0.25	164.2	121.1	1453.3	1674.4

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 225 MPa × 192.47 mm² = 32,479 N

Step 2 — Torque (dry): T = 0.20 × 0.0180 m × 32,479 N = 116.9 N·m

Proof stress per ISO 898-1:2013 Table 4. Stress area per ISO 898-1 Annex A. K-factor per VDI 2230.

Non-critical assemblies, light-duty applications, general-purpose hardware where high strength is not required

• Torque values are for standard hex bolts with ISO metric threads. Socket head cap screws may have different requirements.
• Lubrication reduces required torque significantly — using dry torque values on lubricated bolts risks exceeding yield strength.
• For critical or safety-related applications, always consult the manufacturer's specifications or applicable design standard (e.g., VDI 2230).
• Re-used bolts may have altered friction characteristics. Inspect threads before reuse.

SizeM18

Class4.6

Diameter18 mm

Pitch (coarse)2.5 mm

Tensile400 MPa

Yield240 MPa

Proof225 MPa