What is the material of the steel rails?

What Material Are Steel Rails Made From?

Railway rails are classified into two very different material families. Main-line rails are hot-rolled from high-carbon pearlitic steel, typically U71Mn or U75V in China and R260 or R350HT in Europe, with carbon contents in the range of 0.6-0.8%. These grades give the hardness and wear resistance that heavy wheel loads demand.

Light rails, industrial rails and a wide range of track fittings such as fishplates, base plates and bolt assemblies, however, are often made from lower-carbon structural steels. The most common Chinese structural grade is Q235B (GB/T 700), and its standard European equivalent is S235JR (EN 10025-2).

Q235B and Its European Equivalent S235JR

S235JR is the grade most frequently named as the European equivalent of Q235B. Both are non-alloy structural steels with a minimum yield strength of 235 MPa for thicknesses up to about 16 mm. The chemistry limits are close but not identical, and the difference matters when a drawing specifies one grade and the mill offers the other.

Both grades are weldable and suitable for light-duty structural and track applications. S235JR has a lower maximum carbon content, which slightly improves weldability, while the tensile ranges overlap almost completely. For plates, bars and light sections the two are treated as interchangeable by most fabricators, but any substitution should be confirmed with the project engineer.

Where Q235B Is Used in Track Construction

Q235B is the base material for many non-rail track components: fishplates for light rails, steel base plates under rail seats, sleeper tie plates, and light rails themselves for low-speed industrial sidings, mine railways and crane runways. For these applications the lower carbon content is an advantage, because the components are frequently drilled, punched or welded during installation.

It must not be used for main-line rails. The hardness and wear resistance of Q235B are far below those of pearlitic rail steel, and a Q235B rail on a busy line would wear out within months. The distinction is a matter of traffic, not of quality: light rail grades such as 50Q and 55Q, and heavier structural grades, occupy the middle ground for sidings and workshop tracks.

How to Check the Grade of Delivered Rail

Every delivery of rail or track steel should carry a mill test certificate stating the standard, the grade, the heat number, the ladle analysis and the mechanical test results. On the rail itself, the grade is rolled into the web at regular intervals. If the delivered material is to be used as an equivalent of a specified grade, the certificate must show that all specified limits are met; the word equivalent alone is not a technical approval.

FAQ

Is S235JR exactly the same as Q235B?

Not exactly. The mechanical properties are equivalent, but the maximum carbon limit differs (0.17% for S235JR against 0.22% for Q235B). For most structural applications they are treated as interchangeable.

Can Q235B be used to make main-line rails?

No. Main-line rails need the hardness and wear resistance of high-carbon pearlitic grades such as U71Mn, U75V, R260 or R350HT. Q235B is limited to light rails and track fittings.

What is the tensile strength of Q235B?

Q235B has a tensile strength range of 370-500 MPa and a minimum yield strength of 235 MPa for thicknesses up to about 16 mm, per GB/T 700.

Which European standard covers S235JR?

S235JR is specified in EN 10025-2, the European standard for hot-rolled products of non-alloy structural steels.

What light rail grades are rolled from Q235-type steel?

Chinese light rails for industrial sidings are covered by GB/T 11264. Grades such as 50Q and 55Q are carbon-raised versions used where more wear resistance is needed, while Q235 itself is used for fittings and very light sections.