M45 Grade 10.9 Torque Specification

Torque Values by Surface Condition

Stress area: 1306.09 mm² · Proof load: 1,084,055 N · Clamp load (75%): 813,041 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	7317.4	5397.0	64764.5	74617.0
Oiled	0.15	5488.0	4047.7	48572.9	55962.2
Zinc Plated	0.18	6585.6	4857.3	58287.5	67154.7
Waxed	0.1	3658.7	2698.5	32382.2	37308.5
MoS₂	0.12	4390.4	3238.2	38858.3	44769.8
Galvanized	0.25	9146.7	6746.3	80955.2	93270.7

Stress area: 1397.15 mm² · Proof load: 1,159,634 N · Clamp load (75%): 869,726 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	7827.5	5773.3	69279.2	79818.6
Oiled	0.15	5870.6	4329.9	51959.2	59863.7
Zinc Plated	0.18	7044.8	5196.0	62351.8	71837.2
Waxed	0.1	3913.8	2886.7	34640.1	39909.8
MoS₂	0.12	4696.5	3464.0	41567.5	47891.1
Galvanized	0.25	9784.4	7216.6	86599.3	99773.5

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 830 MPa × 1306.09 mm² = 813,041 N

Step 2 — Torque (dry): T = 0.20 × 0.0450 m × 813,041 N = 7317.4 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.

SizeM45

Class10.9

Diameter45 mm

Pitch (coarse)4.5 mm

Tensile1040 MPa

Yield940 MPa

Proof830 MPa