M45 Grade 5.6 Torque Specification

Torque Values by Surface Condition

Stress area: 1306.09 mm² · Proof load: 365,705 N · Clamp load (75%): 274,279 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	2468.5	1820.7	21848.1	25171.8
Oiled	0.15	1851.4	1365.5	16386.3	18879.1
Zinc Plated	0.18	2221.7	1638.6	19663.7	22655.1
Waxed	0.1	1234.3	910.4	10924.5	12586.4
MoS₂	0.12	1481.1	1092.4	13108.8	15103.1
Galvanized	0.25	3085.6	2275.8	27309.9	31464.5

Stress area: 1397.15 mm² · Proof load: 391,202 N · Clamp load (75%): 293,402 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	2640.6	1947.6	23371.3	26926.7
Oiled	0.15	1980.5	1460.7	17528.9	20195.6
Zinc Plated	0.18	2376.6	1752.9	21034.7	24234.7
Waxed	0.1	1320.3	973.8	11685.6	13463.4
MoS₂	0.12	1584.4	1168.6	14023.1	16156.4
Galvanized	0.25	3300.8	2434.5	29214.6	33658.9

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 280 MPa × 1306.09 mm² = 274,279 N

Step 2 — Torque (dry): T = 0.20 × 0.0450 m × 274,279 N = 2468.5 N·m

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

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.

SizeM45

Class5.6

Diameter45 mm

Pitch (coarse)4.5 mm

Tensile500 MPa

Yield300 MPa

Proof280 MPa