M12 Grade 9.8 Torque Specification

Torque Values by Surface Condition

Stress area: 84.27 mm² · Proof load: 54,776 N · Clamp load (75%): 41,082 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	98.6	72.7	872.7	1005.4
Oiled	0.15	73.9	54.5	654.1	753.6
Zinc Plated	0.18	88.7	65.4	785.1	904.5
Waxed	0.1	49.3	36.4	436.3	502.7
MoS₂	0.12	59.2	43.7	524.0	603.7
Galvanized	0.25	123.2	90.9	1090.4	1256.3

Stress area: 92.07 mm² · Proof load: 59,845 N · Clamp load (75%): 44,884 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	107.7	79.4	953.2	1098.2
Oiled	0.15	80.8	59.6	715.1	823.9
Zinc Plated	0.18	96.9	71.5	857.6	988.1
Waxed	0.1	53.9	39.8	477.1	549.6
MoS₂	0.12	64.6	47.6	571.8	658.7
Galvanized	0.25	134.7	99.3	1192.2	1373.6

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 650 MPa × 84.27 mm² = 41,082 N

Step 2 — Torque (dry): T = 0.20 × 0.0120 m × 41,082 N = 98.6 N·m

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

Heavy-duty automotive, high-performance machinery (limited availability, mostly M16 and smaller)

• 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.

SizeM12

Class9.8

Diameter12 mm

Pitch (coarse)1.75 mm

Tensile900 MPa

Yield720 MPa

Proof650 MPa