M30 Grade 5.6 Torque Specification

Torque Values by Surface Condition

Stress area: 560.59 mm² · Proof load: 156,965 N · Clamp load (75%): 117,724 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	706.3	520.9	6251.3	7202.3
Oiled	0.15	529.8	390.8	4689.1	5402.5
Zinc Plated	0.18	635.7	468.9	5626.4	6482.4
Waxed	0.1	353.2	260.5	3126.1	3601.7
MoS₂	0.12	423.8	312.6	3750.9	4321.6
Galvanized	0.25	882.9	651.2	7814.3	9003.1

Stress area: 621.2 mm² · Proof load: 173,936 N · Clamp load (75%): 130,452 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	782.7	577.3	6927.5	7981.3
Oiled	0.15	587.0	432.9	5195.4	5985.8
Zinc Plated	0.18	704.4	519.5	6234.5	7182.9
Waxed	0.1	391.4	288.7	3464.2	3991.2
MoS₂	0.12	469.6	346.4	4156.3	4788.6
Galvanized	0.25	978.4	721.6	8659.6	9976.9

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 280 MPa × 560.59 mm² = 117,724 N

Step 2 — Torque (dry): T = 0.20 × 0.0300 m × 117,724 N = 706.3 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.

SizeM30

Class5.6

Diameter30 mm

Pitch (coarse)3.5 mm

Tensile500 MPa

Yield300 MPa

Proof280 MPa