ST35.8 pipes and tubes are intended for elevated temperature service and are commonly selected for boilers, economisers and heat exchangers. Amardeep Steel supplies this DIN 17175 carbon steel grade under material number 1.0305. For projects using current European specifications, the corresponding P235GH grade is covered through our EN 10216-2 P235GH tubes. Buyers working to ASTM specifications can also compare our ASTM A192 boiler tubes. For higher temperature applications, our range of boiler tubes includes alloy grades as well. Each order is supplied with mill test certificates to EN 10204, heat treatment records and complete heat traceability.
What Are ST35.8 Pipes and Tubes?
DIN 17175 is the German standard for seamless tubes made from heat resistant steels. St35.8 is its basic carbon steel grade, used where metal temperatures are moderate and pressure is the main design load. The standard has been withdrawn and replaced by EN 10216-2, but many boilers built to DIN drawings are still maintained with St35.8 tube.
ST35.8 Quality Grade I and Grade III
DIN 17175 offers St35.8 in two quality grades. Grade I is the standard supply. Grade III adds extra testing and inspection and is specified for higher pressure and temperature duty. A commonly used rule of thumb is grade I below about 450 degrees Celsius and moderate pressure, and grade III above that; the boiler designer's specification always decides.
ST35.8 Pipes and Tubes Specifications
Parameter | Details |
|---|---|
Standard | DIN 17175 (EN 10216-2 P235GH for current orders) |
Grade | St35.8, quality grade I or III |
Material Number | 1.0305 |
Type | Seamless, hot finished and cold drawn |
Dimensions | As per DIN 2448 / EN 10220 |
Length | Random lengths, fixed lengths and cut lengths |
Heat Treatment | Normalized |
Ends | Plain end and bevelled end |
Test Certificate | EN 10204 3.1, with 3.2 available on request |
ST35.8 Chemical Composition
Element | Content (%) |
|---|---|
Carbon (C) | 0.17 max |
Silicon (Si) | 0.10 to 0.35 |
Manganese (Mn) | 0.40 to 0.80 |
Phosphorus (P) | 0.040 max |
Sulfur (S) | 0.040 max |
ST35.8 Mechanical Properties
Property | Requirement |
|---|---|
Tensile Strength | 360 to 480 MPa |
Yield Strength, min (wall up to 16 mm) | 235 MPa |
Yield Strength, min (heavier walls) | Reduces with wall thickness, down to about 215 MPa |
Elongation, longitudinal, min | 25% |
DIN 17175 also lists minimum proof strength at elevated temperatures, which designers use to size tube walls for boiler service.
ST35.8 Equivalent Grades
Standard | Equivalent Designation |
|---|---|
DIN 17175 | St35.8 (1.0305) |
EN 10216-2 | P235GH (1.0345), closest current grade |
ASTM (pipe) | A106 Grade B (close match) |
ASTM (boiler tube) | A192 (close match) |
BS 3059-2 | Grade 360 (close match) |
Equivalents are close matches, not direct substitutes. See our BS 3059 Grade 360 tubes for the British version.
ST35.8 vs ST45.8 vs P235GH
Property | ST35.8 | ST45.8 | P235GH |
|---|---|---|---|
Standard | DIN 17175 (withdrawn) | DIN 17175 (withdrawn) | EN 10216-2 |
Material Number | 1.0305 | 1.0405 | 1.0345 |
Tensile Strength | 360 to 480 MPa | 410 to 530 MPa | 360 to 500 MPa |
Yield Strength, min | 235 MPa | 255 MPa | 235 MPa |
For more strength at the same temperature, ST45.8 or its successor in our EN 10216-2 P265GH tubes is the next step.
Applications of ST35.8 Pipes and Tubes
- Water wall and economiser tubes in industrial boilers
- Headers and steam lines at moderate temperature
- Base tube for finned tubes in waste heat recovery
- Shell and tube heat exchanger tubes
- Replacement tubes for boilers built to DIN drawings
Testing and Documentation
Every order of ST35.8 pipes and tubes goes through the checks below at our testing facility or approved third party labs.
- Chemical analysis
- Tensile test
- Flattening, flaring or ring expanding tests
- Hydrostatic test or eddy current test
- Ultrasonic testing for grade III or on request
- Visual and dimensional inspection
Mill test certificates are issued to EN 10204 3.1, with 3.2 available on request. You can view our approvals on the certificates page.
Packing and Marking
Each length is marked with the standard, grade, quality grade, size and heat number. Tube ends are capped and lengths are bundled or packed in wooden boxes for export. Read more about our packing and despatch process.
Request a Quote for ST35.8 Pipes & Tubes
Send us the quality grade, OD, wall thickness, length and quantity, and our team will reply with price and delivery. Use the enquiry form or reach us through the contact page.
Frequently Asked Questions
What is ST35.8 material?
ST35.8 is a carbon steel for seamless tubes in elevated temperature service, defined in the German standard DIN 17175 with material number 1.0305. It has a tensile strength of 360 to 480 MPa and a minimum yield of 235 MPa on walls up to 16 mm.
What is the EN equivalent of ST35.8?
The closest current equivalent is P235GH, material 1.0345, in EN 10216-2, the standard that replaced DIN 17175. Check the drawing before substituting.
What is the difference between ST35.8 grade I and grade III?
Grade I is the standard supply. Grade III adds extra testing and inspection and is specified for higher pressure and temperature boiler duty.
What is ST35.8 tube used for?
ST35.8 tube is used for boiler water walls, economisers, headers, heat exchangers and as base tube for finned tubes where metal temperatures are moderate.
