Different materials require different torque specifications. K-factors, proof strength, and installation practices vary significantly between material types.
Torque specifications for stainless steel bolts. K-factors, corrosion resistance...
Torque specifications for alloy steel bolts. Classes 10.9 and 12.9, SAE Grade 8,...
Torque specifications for carbon steel bolts. Classes 4.6 through 8.8, SAE Grade...
Torque specifications for brass bolts and fasteners. Low-strength, non-sparking,...
Torque specifications for titanium bolts. Grade 5 (6Al-4V) properties, weight sa...
Torque tables for steel assume a known proof stress and a known thread friction. Change the material and both move. Stainless steel (ISO 3506 A2-70, A4-80) has a lower 0.2% proof stress than class 8.8 and galls easily, so it is tightened lubricated and to lower values. Brass and aluminium bolts carry only a fraction of steel's load. Titanium Ti-6Al-4V approaches class 10.9 strength but must be installed with anti-seize, which changes the K-factor.
The material of the parts being clamped matters as much as the bolt. A steel bolt threaded into aluminium needs a longer engagement — roughly 2× diameter instead of 1× — or a thread insert, and the aluminium thread, not the bolt, usually sets the torque limit. Dissimilar metals also raise galvanic corrosion risk in wet environments, which is why stainless fasteners in aluminium are commonly isolated or coated.
Each material page lists typical K-factors, the strength basis used and a torque table. For ordinary carbon and alloy steel, use the metric and imperial tables directly.