M64 Grade 4.6 Torque Specification

Torque Values by Surface Condition

Stress area: 2676.0 mm² · Proof load: 602,100 N · Clamp load (75%): 451,575 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	5780.2	4263.3	51159.1	58941.9
Oiled	0.15	4335.1	3197.4	38368.9	44205.9
Zinc Plated	0.18	5202.1	3836.9	46042.5	53046.9
Waxed	0.1	2890.1	2131.6	25579.6	29470.9
MoS₂	0.12	3468.1	2557.9	30695.3	35364.9
Galvanized	0.25	7225.2	5329.0	63948.4	73676.8

Stress area: 2809.0 mm² · Proof load: 632,025 N · Clamp load (75%): 474,019 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	6067.4	4475.1	53701.0	61870.5
Oiled	0.15	4550.6	3356.3	40276.2	46403.4
Zinc Plated	0.18	5460.7	4027.6	48331.3	55683.9
Waxed	0.1	3033.7	2237.5	26850.5	30935.2
MoS₂	0.12	3640.5	2685.1	32221.2	37122.9
Galvanized	0.25	7584.3	5593.9	67126.7	77338.6

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 225 MPa × 2676.0 mm² = 451,575 N

Step 2 — Torque (dry): T = 0.20 × 0.0640 m × 451,575 N = 5780.2 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.

SizeM64

Class4.6

Diameter64 mm

Pitch (coarse)6.0 mm

Tensile400 MPa

Yield240 MPa

Proof225 MPa