M24 Grade 10.9 Torque Specification

Torque Values by Surface Condition

Stress area: 352.5 mm² · Proof load: 292,575 N · Clamp load (75%): 219,431 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	1053.3	776.9	9322.5	10740.7
Oiled	0.15	790.0	582.7	6992.1	8055.8
Zinc Plated	0.18	947.9	699.1	8389.6	9665.9
Waxed	0.1	526.6	388.4	4660.8	5369.8
MoS₂	0.12	632.0	466.1	5593.7	6444.6
Galvanized	0.25	1316.6	971.1	11652.9	13425.6

Stress area: 384.42 mm² · Proof load: 319,069 N · Clamp load (75%): 239,301 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	1148.6	847.2	10166.0	11712.5
Oiled	0.15	861.5	635.4	7624.9	8784.9
Zinc Plated	0.18	1033.8	762.5	9149.9	10541.9
Waxed	0.1	574.3	423.6	5083.0	5856.3
MoS₂	0.12	689.2	508.3	6099.9	7027.9
Galvanized	0.25	1435.8	1059.0	12707.9	14641.1

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 830 MPa × 352.5 mm² = 219,431 N

Step 2 — Torque (dry): T = 0.20 × 0.0240 m × 219,431 N = 1053.3 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.

SizeM24

Class10.9

Diameter24 mm

Pitch (coarse)3.0 mm

Tensile1040 MPa

Yield940 MPa

Proof830 MPa