M48 Grade 4.6 Torque Specification

Torque Values by Surface Condition

Stress area: 1473.19 mm² · Proof load: 331,468 N · Clamp load (75%): 248,601 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	2386.6	1760.3	21123.2	24336.6
Oiled	0.15	1789.9	1320.2	15842.0	18252.0
Zinc Plated	0.18	2147.9	1584.2	19010.5	21902.6
Waxed	0.1	1193.3	880.1	10561.6	12168.3
MoS₂	0.12	1431.9	1056.1	12673.4	14601.4
Galvanized	0.25	2983.2	2200.3	26403.6	30420.3

Stress area: 1602.9 mm² · Proof load: 360,652 N · Clamp load (75%): 270,489 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	2596.7	1915.2	22982.7	26479.1
Oiled	0.15	1947.5	1436.4	17236.8	19859.0
Zinc Plated	0.18	2337.0	1723.7	20684.2	23830.9
Waxed	0.1	1298.3	957.6	11490.9	13239.0
MoS₂	0.12	1558.0	1149.1	13789.5	15887.2
Galvanized	0.25	3245.9	2394.1	28728.6	33099.1

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 225 MPa × 1473.19 mm² = 248,601 N

Step 2 — Torque (dry): T = 0.20 × 0.0480 m × 248,601 N = 2386.6 N·m

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

Non-critical assemblies, light-duty applications, general-purpose hardware where high strength is not required

• 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.

SizeM48

Class4.6

Diameter48 mm

Pitch (coarse)5.0 mm

Tensile400 MPa

Yield240 MPa

Proof225 MPa