Comprehensive Overview of DIN 17175 – Seamless Tubes for High-Temperature Service
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Tianjin Sanon Steel Pipe Co., Ltd. is a stockist. Our stock factory is in Cangzhou City, Hebei Province. Our main sources of goods are boiler pipes, and the representative materials are ASTM A335 P5/P11/P91/P92, ASME SA-106/SA-106M GR.B, GB/T 3087-2008 10#/20#. The representative materials of pipeline pipes are API 5L, API 5CT, the representative materials of petroleum cracking pipes GB/T 9948 are 15MoG/12CrMoVG. GB/T 6479-2013 represents the material 10#/20#, heat exchanger tubes SA179/SA210/SA192, etc., mechanical tubes GB/T 8162 represent the material 10#/20#/Q345/42CrMo, EN10210 represents the material S355JOH/S355J2H, gas cylinder tubes GB1 8248, represent the material 34CrMo4/30CrMo.
—— Sanonpipe, Your Trusted Supplier for Boiler and High-Temperature Pipeline Seamless Tubes
I. Standard Introduction – The Cornerstone of German Industrial Heat-Resistant Steel Tubes
DIN 17175 is the German industry standard for seamless tubes made of heat-resistant steels, titled Seamless tubes of heat-resistant steels. It applies to seamless tubes – including tubes for headers – used in the construction of boilers, pipelines, pressure vessels and equipment for service up to 600 °C and simultaneous high pressures.
By definition: “Steels possessing good mechanical properties even under long-time stressing at high temperatures, up to 600 °C, shall be regarded as being heat-resistant at high temperatures.” The tubes shall be supplied suitably heat-treated over their entire length.
The standard covers a complete spectrum of 9 steel grades, ranging from carbon heat-resistant steels and low-alloy heat-resistant steels to martensitic heat-resistant steels. With decades of application history in German and European boiler and pressure-vessel manufacturing, DIN 17175 remains a widely referenced specification for high-temperature and high-pressure pipeline steels.
Important note: DIN 17175 has largely been superseded by the European harmonised standard EN 10216-2 (Seamless steel tubes for pressure purposes – Technical delivery conditions – Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties). However, the DIN 17175 grade designations are still extensively used worldwide, and many existing plants, older designs and technical specifications continue to cite them. Sanonpipe can supply products according to either DIN 17175 or EN 10216-2, as required by the customer.
II. Application Fields – Core Material Selection for Boiler, Power and Petrochemical Industries
DIN 17175 seamless tubes are primarily used in the following high-temperature and high-pressure applications:
| Application Area | Specific Uses | Operating Conditions |
| Boiler construction | Heating surfaces, water-wall tubes, economiser tubes of high-pressure boilers | Up to 600 °C, high-pressure steam |
| Steam pipelines | Main steam lines, reheat lines, headers | High temperature & pressure, long-term service |
| Pressure vessels | High-temperature pressure vessels and equipment | Pressure + high temperature |
| Power generation | Thermal power and nuclear plant tubing | Critical service components |
| Petrochemical industry | High-temperature process piping, heat exchangers | High temperature + corrosive media |
According to Section 4 of the standard, the choice of steel grade is at the discretion of the customer. Sanonpipe can provide professional material selection advice based on the customer’s specific operating parameters.
III. Material Grades – Full Coverage of Nine Steels
DIN 17175 covers 9 steel grades, ranging from carbon steels to alloyed steels and from ordinary heat-resistant steels to martensitic heat-resistant steels:
| Steel Grade | Material No. | Type | Main Characteristics |
| St35.8 | 1.0305 | Carbon heat-resistant | Basic grade for general boiler tubes |
| St45.8 | 1.0405 | Carbon heat-resistant | Most widely used, higher strength than St35.8 |
| 17 Mn 4 | 1.0481 | Low-alloy heat-resistant | Mn-strengthened, higher strength |
| 19 Mn 5 | 1.0482 | Low-alloy heat-resistant | Mn-strengthened, even higher strength |
| 15 Mo 3 | 1.5415 | Molybdenum heat-resistant | Contains Mo, excellent creep properties |
| 13 CrMo 4 4 | 1.7335 | Cr-Mo heat-resistant | Typical boiler tube steel, superior heat resistance |
| 10 CrMo 9 10 | 1.7380 | Cr-Mo heat-resistant | Higher Cr-Mo content, suitable for higher temperatures |
| 14 MoV 6 3 | 1.7715 | Mo-V heat-resistant | Contains Mo and V, improved high-temperature performance |
| X20 CrMoV 12 1 | 1.4922 | Martensitic heat-resistant | Highest alloy content, max. service temperature 650 °C |
IV. Detailed Description of Key Steel Grades
4.1 St45.8 (Material No. 1.0405) – The Most Widely Used Carbon Heat-Resistant Steel
St45.8 is the most frequently applied carbon heat-resistant steel grade in DIN 17175. “St” stands for Stahl (steel), and “45” indicates a tensile strength level of approximately 450 MPa.
Chemical Composition (%):
| Element | St45.8 Content | Remarks |
| C | ≤ 0.21 | Ensures balance of strength and toughness |
| Si | 0.10 – 0.35 | Improves oxidation and heat resistance |
| Mn | 0.40 – 0.80 | Increases strength and hardenability |
| P | ≤ 0.020 | Strictly controlled to guarantee high-temperature toughness |
| S | ≤ 0.020 | Strictly controlled for hot workability |
Mechanical Properties:
| Property | Value |
| Tensile strength (σb) | 410 – 530 MPa |
| Yield strength (σs) | ≥ 255 MPa |
| Elongation (δ5) | ≥ 21% |
Recommended service temperature: ≤ 500 °C (carbon steels may graphitise when operated above 450 °C for extended periods)
International Equivalent Grades:
| Standard | Equivalent Grade |
| China (GB) | 20G (GB 5310) |
| USA (ASTM) | A106 Grade B |
| Japan (JIS) | STB42 |
| Europe (EN) | P235GH (EN 10216-2) |
4.2 Alloy Heat-Resistant Steel Series (15Mo3 / 13CrMo44 / 10CrMo910)
| Steel Grade | Material No. | Main Alloying Elements | Service Temperature | Typical Application |
| 15Mo3 | 1.5415 | Mo | ≤ 550 °C | Boiler superheaters, reheaters |
| 13CrMo44 | 1.7335 | Cr-Mo | ≤ 580 °C | High-pressure boiler tubes, steam lines |
| 10CrMo910 | 1.7380 | Cr-Mo | ≤ 600 °C | High-temperature, high-pressure steam piping |
4.3 X20CrMoV121 (Material No. 1.4922) – The Highest Temperature Grade
X20CrMoV121 is the highest-alloyed and highest-service-temperature steel in DIN 17175. Key features:
Maximum service temperature: 650 °C
Material type: Martensitic heat-resistant steel
Key properties: High alloy content gives excellent creep strength and steam oxidation resistance
Weldability: Requires special procedures (preheating + post-weld heat treatment)
Typical applications: High-temperature/high-pressure units in imported thermal power plants – main steam piping, superheaters, reheaters, and other critical components
V. Quality Grades – Grade I and Grade III
DIN 17175 defines two quality grades: Grade I and Grade III.
| Quality Grade | Applicable Conditions | Testing Requirements | Typical Applications |
| Grade I | Temperature ≤ 450 °C, pressure ≤ 80 bar | Basic testing | Low- to medium-pressure boilers |
| Grade III | Temperature > 450 °C or pressure > 80 bar | Stricter testing (100% NDT, more frequent ring tests) | High-pressure boilers, superheaters, reheaters |
For carbon steel tubes (St35.8, St45.8), both Grade I and Grade III may apply; for alloy steel tubes, only Grade III is applicable.
VI. Manufacturing Process and Testing Requirements
6.1 Manufacturing Process
According to Section 6.1.1, tubes may be manufactured by hot or cold rolling, hot pressing, hot or cold drawing. The specific process depends on the required dimensions and application.
6.2 Heat Treatment
Tubes shall be supplied suitably heat-treated over their entire length. Depending on the steel type, the following heat treatments may be used:
Normalising (for carbon steels St35.8, St45.8)
Subcritical annealing
Hardening and tempering (for alloy steels)
For 13CrMo44 and 10CrMo910, tempering alone may be adequate under certain conditions. Steels 14MoV63 and X20CrMoV121 must be supplied in the hardened and tempered condition.
6.3 Non-Destructive Testing (NDT)
For Grade III tubes, the standard requires:
100% NDT (ultrasonic testing) for longitudinal defects
Additional testing for transverse defects and/or laminations may be agreed upon
6.4 Ring Tests
Grade III tubes are subject to ring tests, including:
Ring flattening test
Ring expanding test
Ring tensile test
For Grade III tubes with outside diameter ≤ 51 mm, 20% of the rolled lengths are tested; for those > 51 mm, both ends of each rolled length are ring-tested.
VII. International Equivalent Standards
DIN 17175 has several equivalent or interchangeable standards worldwide:
| Standard System | Corresponding Standard | Remarks |
| Europe (EN) | EN 10216-2 | Direct replacement (high-temperature seamless tubes) |
| USA (ASTM) | ASTM A106 / A213 / A335 | High-temperature seamless tubes |
| China (GB) | GB 5310 (high-pressure boiler tubes) | Dedicated boiler tube standard |
| China (GB) | GB 3087 (low/medium-pressure boiler tubes) | Low/medium-pressure boiler tubes |
| UK (BS) | BS 3059 / BS 3602 | Boiler tube standards |
| France (NF) | NF A 49-213 | High-temperature seamless tubes |
VIII. Quick Reference – International Equivalents of Key DIN 17175 Grades
| DIN 17175 Grade | Material No. | China GB | USA ASTM | Europe EN |
| St35.8 | 1.0305 | 20G (approx.) | A106 Grade A | P235GH |
| St45.8 | 1.0405 | 20G | A106 Grade B | P235GH |
| 17Mn4 | 1.0481 | Q345 | — | — |
| 19Mn5 | 1.0482 | Q390 | — | — |
| 15Mo3 | 1.5415 | 15MoG | A209 T1a | — |
| 13CrMo44 | 1.7335 | 15CrMoG | A213 T12 | 13CrMo4-5 |
| 10CrMo910 | 1.7380 | 12Cr2MoG | A213 T22 | 10CrMo9-10 |
| 14MoV63 | 1.7715 | — | — | — |
| X20CrMoV121 | 1.4922 | — | — | — |
IX. Why Choose Sanonpipe?
| Our Advantages | Detailed Description |
| Standard expertise | Deep understanding of DIN 17175 and EN 10216-2 – we interpret and apply every requirement accurately |
| Material assurance | Full coverage from St35.8 to X20CrMoV121; complete material certificates (EN 10204 3.1 / 3.2 available) |
| Comprehensive sizes | Supply range: OD 10–426 mm, WT 1–40 mm – covering all dimensional requirements of DIN 17175 |
| Quality guarantee | Able to meet both Grade I and Grade III requirements – 100% NDT for Grade III tubes |
| Fast delivery | 20,000 tonnes of regular stock; urgent orders shipped within 7–15 days |
| Full-service support | From enquiry and technical clarification, to quotation, documentation and logistics – one-stop delivery |
| Zero-risk commitment | 240+ internal quality control checkpoints; zero discrepancies in documentation |
| CBAM compliance support | Assistance in preparing product carbon footprint data for smooth EU Carbon Border Adjustment Mechanism compliance |
X. Contact Us
Sanonpipe is dedicated to providing global customers with high-quality seamless tubes that meet DIN 17175 specifications. Whether you need boiler tubes, superheater tubes, steam piping or pressure-vessel tubes, we offer professional technical support and flexible supply solutions.
Typical ordering example:
Seamless Steel Tube 51 × 3.0 DIN 17175 – St45.8 III
Tianjin Sanonpipe Co., Ltd.
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info@sanonpipe.com
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