What is the difference between TC4 titanium alloy screws and GR5 titanium alloy screws?

A Quick Summary of TC4 and GR5 Titanium Alloy Screws

TC4 = GR5; the material is exactly the same—both are Ti-6Al-4V (titanium 6, aluminum 4, vanadium 4)—but they are simply different designations under two distinct standard systems.

TC4: GB/T (Chinese National Standard) grade, used in domestic drawings, domestic quality inspection reports, and domestic projects.

GR5 (Grade 5): ASTM (American Standard) grade, used for export trade, drawings from overseas customers, and procurement orders from Europe and the United States.

I. Material Properties

Composition: Ti-6Al-4V

Density: 4.51 g/cm³, approximately 45% lighter than steel

Tensile Strength: ≥895 MPa; Yield Strength: ≥825 MPa

Hardness: HV 320–380 (annealed condition); high strength, non-magnetic, salt spray resistant, and rust-proof

Applications: Structural fasteners for bicycles, motorcycles, automotive modifications, and aerospace applications—including internal star-head screws, flange nuts, and wheel hub bolts

II. The Only Practical Difference

Material Certification

TC4 screws: Come with a GB/T (Chinese National Standard) material certificate.

GR5 screws: Come with an ASTM B348 (U.S. Standard) material certificate, suitable for export customs clearance and factory audits by overseas customers.

Drawing Notations: Domestic drawings specify “TC4”; export drawings specify “GR5” (Grade 5). There is no difference in the raw material bar stock, machining, heat treatment, or mechanical properties of the finished product.

Market Pitfall Alert: A small number of unscrupulous vendors may create confusion: GR5 ≠ GR2 (pure titanium TA2); GR2 is pure titanium with significantly lower strength. Never purchase pure titanium as if it were GR5 titanium alloy. Additionally: TC4 ELI = GR23 (ultra-low-clearance medical grade; this is not the same category as standard TC4/GR5 and must not be used interchangeably).

III. Selection Recommendations

✅ Domestic sales and domestic projects: Specify TC4 ✅ Foreign trade exports, overseas customers, and European/U.S. drawings: Specify GR5 (Grade 5)

For titanium rods from the same batch, domestic test reports can be issued for TC4, and U.S. standard material certificates can be issued for GR5, with no change in the performance of the screws themselves.