M36 Grade 10.9 Torque Specification

Torque Values by Surface Condition

Stress area: 816.72 mm² · Proof load: 677,878 N · Clamp load (75%): 508,408 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	3660.5	2699.8	32398.2	37326.9
Oiled	0.15	2745.4	2024.9	24298.8	27995.4
Zinc Plated	0.18	3294.5	2429.9	29158.8	33594.7
Waxed	0.1	1830.3	1350.0	16199.5	18663.9
MoS₂	0.12	2196.3	1619.9	19438.9	22396.1
Galvanized	0.25	4575.7	3374.9	40498.4	46659.3

Stress area: 864.95 mm² · Proof load: 717,908 N · Clamp load (75%): 538,431 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	3876.7	2859.3	34311.7	39531.5
Oiled	0.15	2907.5	2144.5	25733.6	29648.4
Zinc Plated	0.18	3489.0	2573.4	30880.3	35578.0
Waxed	0.1	1938.4	1429.7	17156.3	19766.3
MoS₂	0.12	2326.0	1715.6	20586.8	23718.7
Galvanized	0.25	4845.9	3574.2	42889.8	49414.6

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 830 MPa × 816.72 mm² = 508,408 N

Step 2 — Torque (dry): T = 0.20 × 0.0360 m × 508,408 N = 3660.5 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.

SizeM36

Class10.9

Diameter36 mm

Pitch (coarse)4.0 mm

Tensile1040 MPa

Yield940 MPa

Proof830 MPa