R350HT vs U75V
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
R350HT
Structural & HSLA Steel
R350HT is the heat-treated premium rail grade of EN 13674-1. In-line head hardening refines the pearlitic microstructure, pushing head hardness to 350–390 HBW and tensile strength above 1175 MPa — the standard answer for heavy-haul lines, sharp curves and high-tonnage metro systems where R260 wears too fast.
Standards: DIN R350HT (EN 13674-1) · GB U75V (near, GB/T 2585)
U75V
Structural & HSLA Steel
U75V is China’s vanadium-microalloyed rail steel to GB/T 2585, the workhorse upgrade over U71Mn for busy passenger and freight lines. Higher carbon, silicon and a small vanadium addition lift as-rolled strength to the 980 MPa class and slow head wear and rolling-contact fatigue.
Standards: DIN R350HT class (near, EN 13674) · GB U75V (GB/T 2585)
Chemical composition compared (%)
| Element | R350HT | U75V |
|---|---|---|
| C | 0.70–0.82 | 0.71–0.80 |
| Si | 0.15–0.58 | 0.50–0.80 |
| Mn | 0.65–1.25 | 0.70–1.05 |
| P | ≤0.020 | ≤0.030 |
| S | ≤0.025 | ≤0.030 |
| Cr | ≤0.30 | — |
| V | — | 0.04–0.12 |
Properties compared
| Property | R350HT | U75V |
|---|---|---|
| Tensile strength | ≥1175 MPa (rail) | ≥980 MPa (as-rolled rail) |
| Hardness | 350–390 HBW (rail head) | ~280–320 HB (rail head, typ.) |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: R350HT · U75V. Substitution decisions for certified parts stay with the design authority.