BOLT SCREW FRICTION COEFFICIENT TABLE

Coefficient of friction table for screw thread friction (μG) and bolt/nut head bearing surface friction (μK) according to VDI 2230 standard.

Coefficient of Friction Table for Screw Bolt Friction
Range for μG and μK Typical Examples
Material - Surfaces Lubricants
0.04 to 0.10 Metallically bright
Black oxide coating
Phosphate conversion coating
Electroplated coatings such as
Zn, Zn/Fe, Zn/Ni
Zinc laminated coatings		 Solid lubricants, such as MoS2,
graphite, PTFE, PA, PE, PI in lubricating varnishes, as top coats or in pastes;
liquefied wax;
wax dispersions
0.08 to 0.16 Metallically bright
Black oxide coating
Phosphate conversion coating
Electroplated coatings such as
Zn, Zn/Fe, Zn/Ni
Zinc laminated coatings
Al and Mg alloys		 Solid lubricants, such as MoS2,
graphite, PTFE, PA, PE, PI in lubricating varnishes, as top coats or in pastes;
liquefied wax ;
wax dispersions, greases;
oils; delivery state
Hot-dip Galvanized  MoS2; graphite; wax dispersions
Organic coatings With integrated solid lubricant
or wax dispersion
Austenitic steel Solid lubricants or waxes; pastes
0.14 to 0.24 Austenitic steel Wax dispersions, pastes
Metallically bright
Phosphate conversion coating		 Delivery state (lightly oiled)
Electroplated coatings such as
Zn, Zn/Fe, Zn/Ni
Zinc laminated coatings		 None
0.20 to 0.35 Austenitic steel Oil
Electroplated coatings such as Zn, Zn/Fe;
Hot-dip galvanized		 None
≥ 0.30 Electroplated coatings such as Zn/Fe, Zn/Ni
Austenitic steel
Al, Mg alloys		 None
Source : From VDI 2230 Part-1 : Systematic calculation of high duty bolted joints - Joints with one cylindrical bolt.

Definitions / Abbreviations:

Austenitic Steel: Austenitic steel is the one of the class of stainless steel. Austenitic steel is the more corrosion resistant because of the high chromium content and nickel additions.

Fe: Iron.

Hot Dip Galvanization: A galvanization process to coat iron and steel with a layer of zinc by immersing the metal in a bath of molten zinc.

MoS2: Molybdenum disulfide.

Ni: Nickel.

PA: Polyamide.

PE: Polyethylene.

PI: Polyimide.

PTFE: Teflon.

Zn: Zinc.

Supplements:

Reference:

  • VDI 2230 Part-1 : Systematic calculation of high duty bolted joints - Joints with one cylindrical bolt