M64 Grade 5.6 Torque Specification

Torque Values by Surface Condition

Stress area: 2676.0 mm² · Proof load: 749,280 N · Clamp load (75%): 561,960 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	7193.1	5305.4	63664.3	73349.5
Oiled	0.15	5394.8	3979.0	47748.0	55011.9
Zinc Plated	0.18	6473.8	4774.8	57298.0	66014.6
Waxed	0.1	3596.5	2652.6	31831.7	36674.2
MoS₂	0.12	4315.9	3183.2	38199.0	44010.1
Galvanized	0.25	8991.4	6631.7	79580.6	91687.1

Stress area: 2809.0 mm² · Proof load: 786,520 N · Clamp load (75%): 589,890 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	7550.6	5569.0	66828.5	76995.0
Oiled	0.15	5662.9	4176.7	50120.9	57745.7
Zinc Plated	0.18	6795.5	5012.1	60145.3	69295.1
Waxed	0.1	3775.3	2784.5	33414.2	38497.5
MoS₂	0.12	4530.4	3341.5	40097.4	46197.4
Galvanized	0.25	9438.2	6961.3	83535.1	96243.2

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 280 MPa × 2676.0 mm² = 561,960 N

Step 2 — Torque (dry): T = 0.20 × 0.0640 m × 561,960 N = 7193.1 N·m

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

Moderate-duty industrial applications, machinery guards, medium-strength connections

• 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

Class5.6

Diameter64 mm

Pitch (coarse)6.0 mm

Tensile500 MPa

Yield300 MPa

Proof280 MPa