Thread and Bearing Friction Coefficient Ranges by Surface and Lubricant (VDI 2230)
VDI 2230 part 1 friction ranges for bolted joints: μG (thread) and μK (bearing) bands from 0.04 to ≥0.30 mapped to surface material/coating families and lubrication states — the assembly-torque basis table.
Last updated: 2026-11
Specifications
Every torque-controlled assembly is a friction guess until this table is consulted. The VDI 2230 part 1 ranges collected here map the realistic μG/μK windows to what is actually on the parts: bright/black-oxide/phosphate/electroplated surfaces with solid-film lubricants run 0.04-0.10; the same surfaces dry or in delivery state sit at 0.08-0.16 and climb to 0.14-0.24 without lubricant; hot-dip galvanizing with MoS2 or wax runs mid-band; austenitic stainless spans wide depending on lubrication and galling tendency; and unlubricated plated or stainless pairs can exceed 0.30. The practical use is preload arithmetic: a torque calculated at μ = 0.12 applied to a dry stainless pair at 0.25 delivers roughly half the intended clamp — this table is where that error gets caught before the joint, not after.
| Source / scope | VDI 2230 part 1 (Systematic calculation of high duty bolted joints) friction ranges for μG (thread) and μK (bearing) — carried verbatim including the source's own closing note |
|---|---|
| 0.04-0.10 | Bright/black oxide/phosphate/electroplated (Zn, Zn/Fe, Zn/Ni), zinc-laminate surfaces; solid lubricants (MoS2, graphite, PTFE, PA, PE, PI) in varnishes, pastes, wax dispersions |
| 0.08-0.16 | Same surfaces + Al/Mg alloys; solid lubricants, greases, oils, delivery state; hot-dip galvanized with MoS2/graphite/wax; organic coatings with integrated solid lubricant |
| 0.14-0.24 | Austenitic steel (waxes/pastes); bright/phosphate delivery state (lightly oiled); electroplated with no lubricant |
| 0.20-0.35 and ≥0.30 | Austenitic with oil; plated/hot-dip without lubricant; ≥0.30 for Zn/Fe, Zn/Ni plated, austenitic, Al/Mg dry — the unlubricated top of the scale |
| Not tabulated | Per-finish K factors (separate registered page), temperature effects, repeated-assembly degradation — per RFQ / joint testing |
Materials
- Friction is a system property of the pair as installed: surface family from this table, lubrication state from the assembly instruction, and scatter of ±20% or more inside any band. Specify both on torque-critical work — "phosphate, oiled, μ target 0.12" is a specification; "tighten to 200 N·m" alone is not. Stainless and hot-dip galvanized are the two families that punish missing lubrication the hardest (galling and high μ respectively), and both are the cheapest to fix with a specified thread lubricant at assembly
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (Thread and Bearing Friction Coefficient Ranges by Surface and Lubricant (VDI 2230)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
How do I use these ranges to sanity-check a torque specification?
Take the target preload from the joint design, pick the μ band matching the actual surface and lubrication from this table, and check the spread: the torque needed at the top of the band versus the bottom tells you the preload scatter you are accepting. If T = F·(0.16P + 0.58·d2·μG + Dk/2·μK) at μ 0.08 gives your 200 N·m wrench setting, the same joint at 0.16 needs nearly double the torque for the same preload — so a specification that ignores the band is delivering whatever the friction feels like that day. Tight bands (solid-film lubricants, controlled coatings) are how critical joints get predictable; the table shows exactly which surface/lubricant combinations buy that predictability.
Why is stainless steel its own row family in the table?
Austenitic stainless threads behave differently from carbon steel: higher adhesion tendency (galling), friction that rises sharply when unlubricated, and wide scatter depending on surface finish and speed. The table gives austenitic steel its own rows in every band for that reason — lubricated with pastes or waxes it sits low-mid; dry it climbs to the top of the scale. Assembly practice follows: specify an anti-galling lubricant on stainless fasteners, control the tightening speed, and expect the first tightening of a fresh nut to run higher friction than subsequent ones. The rows are the standard's acknowledgement that "stainless" is not one friction condition.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support