M45 Grade 12.9 Torque Specification

Torque Values by Surface Condition

Stress area: 1306.09 mm² · Proof load: 1,266,907 N · Clamp load (75%): 950,180 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	8551.6	6307.3	75688.1	87202.4
Oiled	0.15	6413.7	4730.5	56766.1	65401.8
Zinc Plated	0.18	7696.5	5676.6	68119.8	78482.7
Waxed	0.1	4275.8	3153.7	37844.0	43601.2
MoS₂	0.12	5131.0	3784.4	45413.2	52321.8
Galvanized	0.25	10689.5	7884.2	94610.1	109003.0

Stress area: 1397.15 mm² · Proof load: 1,355,236 N · Clamp load (75%): 1,016,427 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	9147.8	6747.1	80964.9	93281.9
Oiled	0.15	6860.9	5060.3	60724.1	69962.0
Zinc Plated	0.18	8233.1	6072.4	72869.1	83954.6
Waxed	0.1	4573.9	3373.5	40482.4	46641.0
MoS₂	0.12	5488.7	4048.3	48579.1	55969.4
Galvanized	0.25	11434.8	8433.9	101206.6	116602.9

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 970 MPa × 1306.09 mm² = 950,180 N

Step 2 — Torque (dry): T = 0.20 × 0.0450 m × 950,180 N = 8551.6 N·m

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

Socket head cap screws, racing/motorsport, aerospace, maximum strength applications — highest standard grade

• 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

Class12.9

Diameter45 mm

Pitch (coarse)4.5 mm

Tensile1220 MPa

Yield1100 MPa

Proof970 MPa