M6 Grade 4.6 Torque Specification

Torque Values by Surface Condition

Stress area: 20.12 mm² · Proof load: 4,527 N · Clamp load (75%): 3,395 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	4.1	3.0	36.3	41.8
Oiled	0.15	3.1	2.3	27.4	31.6
Zinc Plated	0.18	3.7	2.7	32.7	37.7
Waxed	0.1	2.0	1.5	17.7	20.4
MoS₂	0.12	2.4	1.8	21.2	24.5
Galvanized	0.25	5.1	3.8	45.1	52.0

Stress area: 22.03 mm² · Proof load: 4,957 N · Clamp load (75%): 3,718 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	4.5	3.3	39.8	45.9
Oiled	0.15	3.3	2.4	29.2	33.7
Zinc Plated	0.18	4.0	3.0	35.4	40.8
Waxed	0.1	2.2	1.6	19.5	22.4
MoS₂	0.12	2.7	2.0	23.9	27.5
Galvanized	0.25	5.6	4.1	49.6	57.1

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 225 MPa × 20.12 mm² = 3,395 N

Step 2 — Torque (dry): T = 0.20 × 0.0060 m × 3,395 N = 4.1 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.

SizeM6

Class4.6

Diameter6 mm

Pitch (coarse)1.0 mm

Tensile400 MPa

Yield240 MPa

Proof225 MPa