EN 10208
EN 10208 - industrial steel pipe
DIN 17175 ST35.8 seamless steel tubes are a standard used for manufacturing high-pressure boilers and pressure pipes.
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DIN 17175 ST35.8 seamless steel tubes are heat-resistant tubes made of high-quality carbon steel material that adhere to the German standard DIN 17175.
DIN 17175 St45.8 seamless steel tubes are high-pressure boiler tubes made from carbon and low-alloy steels. The tubes are designed to withstand high temperatures and pressures, making them suitable for use in power plants, chemical plants, and other industrial applications that require high-performance tubes.
The DIN 17175 ST35.8 standard specifies the dimensions and technical requirements for these tubes.
These seamless steel tubes are commonly used in power plants, chemical industries, petroleum refineries, and other industries that require high-temperature and high-pressure piping systems. They are also used in the construction of boilers, heat exchangers, and other equipment that require durable and reliable piping systems.
DIN 17175 ST35.8 seamless steel tubes are an important component in various industrial applications where high-pressure and high-temperature piping systems are required to operate safely and efficiently.
Hot working is possible from 1100 to 850°C, and the temperature can be reduced to 750 °C during processing.
| Steel Grade | Thermal processing ℃ | Normalizing℃ | Tempering | ||
| Grade | Material number | Quenching temperature ℃ | Tempering temperature ℃ | ||
| St35.8 | 1.0305 | 1100 to 850°C | 900-930 | - | - |
| Standard | Grade | Chemical composition | |||||
| C | Si | Mn | P、S | Cr | Mo | ||
| DIN 17175 | St35.8 | ≤0.17 | 0.10-0.35 | 0.40-0.80 | ≤0.030 | / | / |
| Standard | Grade | Tensile Strength(MPa) | Yield Strength(MPa) | Elongation(%) |
| DIN 17175 | St35.8 | 360-480 | ≥235 | ≥25 |
| Project | Standard | Size range | Tolerance | |||
| Outer diameter | DIN17175 | Hot rolled steel pipe | OD ≤ 100mm | ± 0.75%( Min ± 0.5mm ) | ||
| OD＞ 100~ 320mm | ± 0.9% | |||||
| Cold drawn steel pipe OD ≤ 120mm | ± 0.6%( Min ± 0.25mm ) | |||||
| Wall thickness | DIN17175 | OD ≤ 130mm | WT ≤ 2Sn | +15%~-10% | ||
| WT ＞ 2Sn~4Sn | +12.5%~-10% | |||||
| WT ＞ 4Sn | ± 9% | |||||
| 130 ＜ OD ≤ 320mm | WT ≤ 0.05OD | +17.5%~-12.5% | ||||
| 0.05OD ＜ WT ≤ 0.11OD | ± 12.5% | |||||
| WT ＞ 0.11OD | ± 10% | |||||
The tube should meet the requirements of the ring test. For the expansion rate (diameter change) of the ring-shaped flaring experiment, no impermissible defects (such as cracks, crepe, folding, and delamination) shall occur during the test.
The tube must have a manufacturing method that achieves a relatively smooth inner and outer surface, so that it is possible to use either a hot rolling method or a cold rolling method. Tubes should not have unacceptable cracks, creases and folds. As long as the wall thickness of the steel pipe does not exceed the allowable dimensional deviation, and does not affect the performance of the steel pipe, it is permissible to create some uneven and shallow longitudinal scratches during the manufacturing process. Mechanical machining (such as buffing) can be used to remove the slight subsidence of the surface, but not to reduce the minimum allowable wall thickness.
Reference data for heat treatment temperature
Hot working is possible from 1100 to 80 ° °C, and the temperature can be reduced to 750 °C during processing.
In the matching-correction work of the local department, attention should be paid to the effective specification of hot work; there should be a supervisory temperature system. In the higher temperature range, ie 1100 to 900 °C, it is suitable for forging and pier thickening, about 85 °C, and the temperature can be lowered to above 75 °C during the processing.
For example, before the last process, or during the same hot working process, if the heating temperature of the workpiece is above the normalizing temperature but not more than 1000 ° C, and the deformation process is above 75 ° C, or ———— In the last process, the degree of deformation does not exceed 5% - at the end of 7 00 °C, then the normalizing of the St35.8, St45.8, 17Mn4, 19Mn5, and 15Mo3 steels is superfluous. The 13CrMo44 and 10CrMo910 only need to be tempered.
For multiple times and/or long time heat treatments at temperatures around 1000 to 1000 °C, the workpiece should be cooled to around 350 °C before the last deformation process. If the normalizing or quenching and tempering treatment is more than enough, then the temperature at which the steel is hot-worked should not exceed 1 000 °C.
Conversely, if the molding end temperature is above 10 °C, then the St35.8, St45.8, 17Mn4, 19Mn5, and 15Mo3 steels must be normalized, while the 13CrMo44 and 10CrMo910 should be tempered.
14MoV63 and X20CrMoV121 steels should be reconditioned after hot work.
Pipes made of steel according to this standard may be cold-worked, such as pipe bending, flaring, drawing and pipe cutting; for X20CrMoV121 and 14CrV63 steels, the high yield point and tensile strength shall be noted. After bending, expanding, and cold drawing with normal deformation, there is no need to supplement the heat treatment.
With years of expertise, we provide a wide range of steel tube processing services. From basic sawing and machining to complex bending and upsetting operations, we support you at every stage of your project.
Our capabilities include eccentricity reduction and concentricity improvement through turning and grinding. We specialize in creating complex geometries using rotary swaging and axial forming, and offer property modifications through partial heat treatment to meet your exact requirements.
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| Condition | Typical Application |
|---|---|
| High Temperature | Boilers, superheaters, steam headers |
| Low Temperature | Cryogenic processing systems |
| High Pressure | Power & process piping |
| Corrosive Media | Chemical & petrochemical plants |
| Creep Service | Thermal power stations |
| Product | Specification |
|---|---|
| Seamless Pipes | ASTM A335 P1 / P5 / P9 / P11 / P22 / P91 |
| Butt Weld Fittings | ASTM A234 WP1 / WP5 / WP9 / WP11 / WP22 / WP91 |
| Forged Fittings & Flanges | ASTM A182 F1 / F5 / F9 / F11 / F22 / F91 |
Sunny Steel supplies alloy steel piping systems worldwide, supporting projects that demand certified materials, full traceability and long-term operational reliability.
Steel pipe delivery status(condition): cold / hard (BK), cold / soft (BKW), after cold stress relief annealing (BKS), annealing (GBK), normalized (NBK).
| Term | Symbol | Explanation |
|---|---|---|
| Cold-finished/hard (cold-finished as-drawn) | BK | No heat treatment after the last cold-forming process. The tubes therefore have only low deformability. |
| Cold-finished/soft (lightly cold-worked) | BKW | After the last heat treatment there is a light finishing pass (cold drawing). With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits. |
| Annealed | GBK | After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum. |
| Normalized | NBK | The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum. |
The general cold strip mills, volume should go through continuous annealing (CAPL unit) to eliminate cold hardening and rolling stress, or batch annealing reach the mechanical properties of the corresponding standard specifies. Cold rolled steel surface quality, appearance, dimensional accuracy better than hot-rolled plate, and right-rolled thin product thickness is about 0.18mm, so the majority of users favor.
Cold rolled steel coil substrate products deep processing of high value-added products. Such as electro-galvanized, hot dip galvanized, electro-galvanized fingerprint resistant, painted steel roll damping composite steel, PVC laminating steel plates, etc., so that the excellent quality of these products has a beautiful, high resistance to corrosion, has been widely used.
Cold rolled steel coil finishing after annealing, cut the head, tail, trimming, flattening, smooth, heavy volume, or longitudinal clipboard. Cold-rolled products are widely used in automobile manufacturing, household electrical appliances, instruments, switches, buildings, office furniture and other industries. Steel plate strapping package weight of 3 to 5 tons. Flat sub-volume typically 3 to 10 tons / volume. Coil diameter 6m.
Bare packing/bundle packing/crate packing/wooden protection at the both sides of tubes and suitably protected for seaworthy delivery or as requested.
There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method to work: prevent rusting and sea transportation security.
Our packing can meet any needs of the customers.
Ceramic lined pipe is made through self-propagating high-temperature synthesis (SHS) technique.
Cast basalt lined steel pipe is composed by lined with cast basalt pipe, outside steel pipe and cement mortar filling between the two layers.
Ceramic tile lined pipes have very uniform coating of specially formulated ceramic material that is affixed to the inner of the pipe.
The material of the rare earth alloy wear-resistant pipe is ZG40CrMnMoNiSiRe, which is also the grade of rare earth alloy steel.
Tubes Erosion Shields are used to protect boiler tubing from the highly erosive effects of high temperatures and pressures thereby greatly extending tube life.
The ASTM A213 T91 seamless tubes are primarily used for boiler, superheater, and heat-exchanger.
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