ST37 Seamless Steel Tube | St37-2 / S235JR / 1.0037 and St37.4 / E235 / 1.0308
PRODUCT DESCRIPTION
ST37 seamless steel tubes are hot-finished or cold-drawn low-carbon steel tubes used in general mechanical systems, manufacturing and precision-tube applications. The applicable tube standard, delivery condition and certificate must be specified when orderMATERIAL INFORMATION
ST37 Seamless Steel Tube
ST37 seamless steel tube is a widely used historical market designation for low-carbon steel tube families supplied in hot-finished or cold-drawn conditions for general manufacturing and mechanical applications.
However, ST37 is not one current and universal tube standard. The production method, tube standard, material designation, outside diameter, wall thickness, delivery condition and EN 10204 3.1 certificate requirement should be stated clearly in the order.
ST37 Tube Designations and Current References
| Historical / Commercial Designation | Close Modern Reference | Material Number | Use and Description |
|---|---|---|---|
| St37-2 | S235JR | 1.0037 | General structural-steel reference commonly used in long-product and plate applications. It is not a tube standard by itself. |
| St37.4 | E235 | 1.0308 | Reference used for cold-drawn precision seamless-tube and mechanical-tube applications. |
| St37.2 tube family | S235JRH | 1.0039 | Structural hollow-section reference. It may be welded or hot-finished; seamless manufacture must be confirmed by the certificate. |
Important note: S235JR / 1.0037, E235 / 1.0308 and S235JRH / 1.0039 are not the same material. They may be mentioned within the low-carbon ST37 family, but their product standards and delivery conditions can differ. One grade should not be substituted directly for another without certificate review.
Hot-Finished and Cold-Drawn ST37 Tubes
| Tube Type | Main Characteristic | Typical Application |
|---|---|---|
| Hot-finished seamless tube | Broader diameter and wall-thickness options for general mechanical and structural use | Machine parts, construction, general fabrication and mechanical-support applications |
| Cold-drawn seamless precision tube | Tighter dimensional tolerance, smooth surface and controlled internal and external diameters | Hydraulic and pneumatic lines, precision mechanical components, automotive and machining applications |
Hot-finished and cold-drawn tubes are not the same product. Outside-diameter and wall-thickness tolerances, surface condition, straightness, mechanical properties and subsequent forming behavior can differ. A hot-finished tube should therefore not automatically be offered in place of a cold-drawn precision-tube requirement.
Chemical Composition: St37-2 / S235JR Reference
The following table provides a general material reference for the St37-2 / S235JR / 1.0037 family. These values do not automatically apply to every seamless-tube certificate; the relevant tube standard and certificate govern.
| Element | General S235JR Reference |
|---|---|
| Carbon (C) | max. 0.17% May vary by applicable standard in thicker sections |
| Manganese (Mn) | max. 1.40% |
| Phosphorus (P) | max. 0.035% |
| Sulfur (S) | max. 0.035% |
| Nitrogen (N) | max. 0.012% |
Older ST37 standards may show phosphorus and sulfur limits of 0.045%. The applicable value for a current order is the chemistry on the quoted tube standard and 3.1 certificate.
Mechanical Properties and Delivery Condition
It is not technically correct to assign one mechanical-property range to every ST37 seamless tube. Mechanical properties depend on the tube standard, hot-finished or cold-drawn production method, outside diameter, wall thickness and delivery condition.
For example, the following values can be seen for an E235 +N cold-drawn precision seamless-tube reference:
| Property | E235 +N Reference Value |
|---|---|
| Yield Strength | min. 235 MPa |
| Tensile Strength | 340 – 470 MPa |
| Elongation A5 | min. 25% |
These values are a general E235 +N reference only. They do not apply to every tube marketed under the ST37 name. Final mechanical values must be taken from the certificate of the quoted product.
Production and Delivery Conditions
Depending on the application, the following delivery conditions can be evaluated for ST37 seamless-tube requirements:
- Hot-finished: For general mechanical and structural tube applications
- Cold-drawn: For tighter tolerance, smoother surface and dimensional control
- +C: Cold-drawn condition
- +N: Normalized or normalized-annealed condition
- Cut lengths: Prepared according to project or manufacturing dimensions
A seamless production requirement must be stated explicitly in the order. A tube referred to only as ST37 or S235 is not automatically a seamless-manufactured tube.
Machinability, Forming and Weldability
Low-carbon tube families associated with ST37 can provide good weldability and formability when supplied to an appropriate product standard and delivery condition. Cold-drawn precision tubes may be preferred for bending, expanding and mechanical-manufacturing applications when supplied in a suitable condition.
Where welding is required, the welding process should be selected according to wall thickness, service condition, welding position and the applicable product standard. Welding heat can affect straightness and surface condition in close-tolerance cold-drawn tubes.
Applications
- Machine manufacturing and general mechanical systems
- Shaft, bush, pin and machined mechanical-component production
- Hydraulic and pneumatic system tubes
- Automotive, agricultural-machinery and equipment components
- General construction and non-pressure structural steel fabrication
- Applications requiring cold-drawn precision tubes and controlled tolerances
Frequently Asked Questions
Is ST37 seamless tube the same product as ST37 transmission shaft steel?
No. ST37 transmission shaft steel is a cold-drawn round or hexagonal solid-bar product. ST37 seamless tube is hollow and follows different manufacturing standards and dimensional rules.
Are ST37, S235JR and E235 the same material?
No. These designations may be mentioned within the same low-carbon steel family, but they are associated with different product standards and applications. S235JR / 1.0037 is a general structural-material reference, while E235 / 1.0308 is a separate reference used for cold-drawn precision-tube applications.
Can ST37 tube be hot-finished or cold-drawn?
Yes. Both hot-finished and cold-drawn tube forms can occur within the ST37 family. Since their tolerance, surface condition and mechanical behavior differ, the production method must be specified in the order.
Can ST37 tube be used for boiler or pressure-vessel service?
Only tubes certified to the applicable pressure-service standard should be used for boiler and pressure-vessel applications. The commercial ST37 designation must not automatically be substituted for P235GH or another pressure-grade material.
Request a Quote from Saf Çelik
For ST37 seamless-tube requirements, please share the required manufacturing route, seamless-production requirement, material reference, outside diameter, wall thickness, length, delivery condition, tolerance and certification need. Saf Çelik can help identify the appropriate hot-finished or cold-drawn tube option for your project.