M22 Grade 10.9 Torque Specification

Torque Values by Surface Condition

Stress area: 303.4 mm² · Proof load: 251,822 N · Clamp load (75%): 188,866 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	831.0	612.9	7355.0	8473.9
Oiled	0.15	623.3	459.7	5516.7	6355.9
Zinc Plated	0.18	747.9	551.6	6619.5	7626.5
Waxed	0.1	415.5	306.5	3677.5	4236.9
MoS₂	0.12	498.6	367.7	4413.0	5084.3
Galvanized	0.25	1038.8	766.2	9194.2	10592.9

Stress area: 333.01 mm² · Proof load: 276,398 N · Clamp load (75%): 207,299 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	912.1	672.7	8072.8	9300.9
Oiled	0.15	684.1	504.6	6054.8	6975.9
Zinc Plated	0.18	820.9	605.5	7265.6	8370.9
Waxed	0.1	456.1	336.4	4036.8	4650.9
MoS₂	0.12	547.3	403.7	4844.0	5580.9
Galvanized	0.25	1140.1	840.9	10090.7	11625.8

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 830 MPa × 303.4 mm² = 188,866 N

Step 2 — Torque (dry): T = 0.20 × 0.0220 m × 188,866 N = 831.0 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.

SizeM22

Class10.9

Diameter22 mm

Pitch (coarse)2.5 mm

Tensile1040 MPa

Yield940 MPa

Proof830 MPa