M6 Grade 10.9 Torque Specification

Torque Values by Surface Condition

Stress area: 20.12 mm² · Proof load: 16,700 N · Clamp load (75%): 12,525 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	15.0	11.1	132.8	153.0
Oiled	0.15	11.3	8.3	100.0	115.2
Zinc Plated	0.18	13.5	10.0	119.5	137.7
Waxed	0.1	7.5	5.5	66.4	76.5
MoS₂	0.12	9.0	6.6	79.7	91.8
Galvanized	0.25	18.8	13.9	166.4	191.7

Stress area: 22.03 mm² · Proof load: 18,285 N · Clamp load (75%): 13,714 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	16.5	12.2	146.0	168.3
Oiled	0.15	12.3	9.1	108.9	125.4
Zinc Plated	0.18	14.8	10.9	131.0	150.9
Waxed	0.1	8.2	6.0	72.6	83.6
MoS₂	0.12	9.9	7.3	87.6	101.0
Galvanized	0.25	20.6	15.2	182.3	210.1

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 830 MPa × 20.12 mm² = 12,525 N

Step 2 — Torque (dry): T = 0.20 × 0.0060 m × 12,525 N = 15.0 N·m

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

Structural steel (equivalent to ASTM A490), heavy machinery, high-strength critical joints, pressure vessels

• 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

Class10.9

Diameter6 mm

Pitch (coarse)1.0 mm

Tensile1040 MPa

Yield940 MPa

Proof830 MPa