M22 Grade 5.6 Torque Specification

Torque Values by Surface Condition

Stress area: 303.4 mm² · Proof load: 84,952 N · Clamp load (75%): 63,714 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	280.3	206.7	2480.9	2858.3
Oiled	0.15	210.3	155.1	1861.3	2144.5
Zinc Plated	0.18	252.3	186.1	2233.0	2572.8
Waxed	0.1	140.2	103.4	1240.9	1429.6
MoS₂	0.12	168.2	124.1	1488.7	1715.2
Galvanized	0.25	350.4	258.4	3101.3	3573.1

Stress area: 333.01 mm² · Proof load: 93,243 N · Clamp load (75%): 69,932 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	307.7	226.9	2723.4	3137.7
Oiled	0.15	230.8	170.2	2042.8	2353.5
Zinc Plated	0.18	276.9	204.2	2450.8	2823.6
Waxed	0.1	153.9	113.5	1362.1	1569.3
MoS₂	0.12	184.6	136.2	1633.8	1882.4
Galvanized	0.25	384.6	283.7	3404.0	3921.8

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 280 MPa × 303.4 mm² = 63,714 N

Step 2 — Torque (dry): T = 0.20 × 0.0220 m × 63,714 N = 280.3 N·m

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

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.

SizeM22

Class5.6

Diameter22 mm

Pitch (coarse)2.5 mm

Tensile500 MPa

Yield300 MPa

Proof280 MPa