Marine Seamless Steel Pipe
Marine Seamless Steel Pipe - industrial steel pipe
GB/T18984 low-temperature heat exchanger tubes refer to seamless steel tubes that conform to the GB/T18984 standard.
GB/T 18984 is a Chinese national standard that specifies the requirements for seamless steel tubes used in low-temperature heat exchangers. The standard was published on December 30, 2016, and came into effect on September 1, 2017. It replaces the previous version, GB/T 18984-2003.
This standard applies to seamless steel tubes used in low-temperature piping systems, specifically for temperatures ranging from -45°C to -196°C. It covers the classification, nomenclature, ordering content, dimensions, shapes, weights, technical requirements, testing methods, inspection rules, packaging, marking, and quality certificates.
Compared to the previous version (GB/T 18984-2003), the current standard includes updates to technical requirements and testing methods to align with international standards.
GB/T 18984 provides essential guidelines for the production and testing of low-temperature heat exchanger tubes, ensuring their safety and reliability in various industrial applications. For detailed specifications and requirements, it is recommended to refer to the full text of the GB/T 18984 standard.
GB/T18984-2003 standard suitable for -49 to -148 degrees F cryogenic pressure vessel piping, and low-temperature heat exchanger tubes seamless steel pipe. GB/T18984 is a Chinese standard that specifies the technical requirements for seamless steel tubes used in low-temperature heat exchanger applications. It covers tubes for working temperatures ranging from -45°C to -196°C.
GB/T18984 low-temperature heat exchanger tubes are specifically designed for use in low-temperature heat exchange systems. These tubes are suitable for conveying fluids at extremely low temperatures, such as in cryogenic applications.
The standard does not explicitly mention specific grades for low-temperature heat exchanger tubes. However, other sources indicate that common grades used for these tubes include 16MnDG and 10CrMo910.
GB/T18984 low-temperature heat exchanger tubes are typically manufactured through processes such as hot rolling or cold drawing. These processes ensure the tubes have precise dimensions, smooth surfaces, and good mechanical properties.
GB/T18984 low-temperature heat exchanger tubes are available from manufacturers and suppliers in China. They come in different sizes and specifications to meet specific project requirements.
| Grade | C | Si | Mn | P(max) | S | Ni | Mo | V |
|---|---|---|---|---|---|---|---|---|
| 16MnDG | 0.12-0.20 | 0.20-0.55 | 1.20-1.60 | 0.025 | 0.025 | - | - | - |
| 10MnDG | <=0.13 | 0.17-0.37 | <=1.35 | 0.025 | 0.025 | - | - | <=0.07 |
| 09DG | <=0.12 | 0.17-0.37 | <=0.95 | 0.025 | 0.025 | - | - | <=0.07 |
| 09Mn2VDG | <=0.12 | 0.17-0.37 | <=1.85 | 0.025 | 0.025 | - | - | <=0.12 |
| 06Ni3MoDG | <=0.08 | 0.17-0.37 | <=0.85 | 0.025 | 0.025 | 2.5-3.7 | 0.15-0.30 | <=0.05 |
| Grade | Tensile strength | Lower yield strength（Rcl/Mpa） | Elongation | |
|---|---|---|---|---|
| Rm/Mpa | W.T.<=16mm | W.T.>16mm | A/% | |
| 16MnDG | 490-665 | >=325 | >=315 | >=30 |
| 10MnDG | >=400 | >=240 | >=35 | |
| 09DG | >=385 | >=210 | >=35 | |
| 09Mn2VDG | >=450 | >=300 | >=30 | |
| 06Ni3MoDG | >=455 | >=250 | >=30 | |
GB seamless steel pipes are widely produced in China, available in various sizes, grades and surface finishes to meet specific project requirements.
According to industry statistics, there are more than 240 national standard steel pipe manufacturers and 250 seamless steel pipe production lines in China.
| Grade | C | Si | Mn | Cr | Ni | Mo | P ≤ | S ≤ | Ti | Cu ≤ |
|---|---|---|---|---|---|---|---|---|---|---|
| Q195 | 0.06–0.12 | ≤0.30 | 0.25–0.50 | ≤0.3 | ≤0.3 | – | 0.045 | 0.050 | – | 0.30 |
| Q235 | 0.14–0.22 | ≤0.30 | 0.30–0.65 | ≤0.3 | ≤0.3 | – | 0.045 | 0.050 | – | 0.30 |
| Q345B | ≤0.20 | ≤0.55 | 1.00–1.60 | – | – | – | 0.040 | 0.040 | – | – |
| 10# | 0.07–0.13 | 0.07–0.37 | 0.35–0.65 | ≤0.15 | ≤0.3 | – | 0.035 | 0.035 | – | 0.25 |
| 20# | 0.17–0.23 | 0.07–0.37 | 0.35–0.65 | ≤0.25 | ≤0.3 | – | 0.035 | 0.035 | – | 0.25 |
| 35# | 0.32–0.39 | 0.07–0.37 | 0.50–0.80 | ≤0.25 | ≤0.3 | – | 0.035 | 0.035 | – | 0.25 |
| 45# | 0.42–0.50 | 0.07–0.37 | 0.50–0.80 | ≤0.25 | ≤0.3 | – | 0.035 | 0.035 | – | 0.25 |
| 20Cr | 0.18–0.24 | 0.07–0.37 | 0.50–0.80 | 0.70–1.00 | ≤0.3 | – | 0.035 | 0.035 | – | 0.30 |
| 40Cr | 0.37–0.44 | 0.07–0.37 | 0.50–0.80 | 0.80–1.10 | ≤0.3 | – | 0.035 | 0.035 | – | 0.30 |
| 20CrMo | 0.17–0.24 | 0.07–0.37 | 0.40–0.70 | 0.80–1.10 | ≤0.3 | 0.15–0.25 | 0.035 | 0.035 | – | 0.30 |
| 35CrMo | 0.32–0.40 | 0.07–0.37 | 0.40–0.70 | 0.80–1.10 | ≤0.3 | 0.15–0.25 | 0.035 | 0.035 | – | 0.30 |
| 42CrMo | 0.38–0.45 | 0.07–0.37 | 0.50–0.80 | 0.90–1.20 | 1.00–1.40 | 0.15–0.25 | 0.035 | 0.035 | – | 0.30 |
| 20CrMoTi | 0.17–0.23 | 0.07–0.37 | 0.40–0.70 | 0.45–0.75 | ≤0.3 | – | 0.035 | 0.035 | – | 0.30 |
| 35Mn2 | 0.32–0.39 | 0.07–0.37 | 1.40–1.80 | ≤0.3 | ≤0.3 | – | 0.035 | 0.035 | – | 0.30 |
| 40Mn2 | 0.37–0.44 | 0.07–0.37 | 1.40–1.80 | ≤0.3 | ≤0.3 | – | 0.035 | 0.035 | – | 0.30 |
| 35SiMn | 0.32–0.40 | 1.10–1.40 | 1.10–1.40 | ≤0.3 | ≤0.3 | – | 0.035 | 0.035 | – | 0.30 |
| 15Mn | 0.12–0.16 | 0.07–0.37 | 0.70–1.00 | ≤0.25 | ≤0.3 | – | 0.035 | 0.035 | – | 0.25 |
| 20Mn | 0.17–0.23 | 0.07–0.37 | 0.70–1.00 | ≤0.25 | ≤0.3 | – | 0.035 | 0.035 | – | 0.25 |
| Class | Tolerance |
|---|---|
| D1 | ±1.5%，min ±0.75 mm |
| D2 | ±1.0%，min ±0.50 mm |
| D3 | ±0.75%，min ±0.30 mm |
| D4 | ±0.50%，min ±0.10 mm |
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.
Seamless steel pipe is regularly used in the transportation of fluids such as water, natural gas, waste and air. It is also regularly required in many high-pressure, high-corrosive environments such as in the oil & gas, power generation and pharmaceutical industries. Some common uses of seamless pipes include:
Chemical composition inspection, mechanical properties test(tensile strength,yield strength, elongation, flaring, flattening, bending, hardness, impact test), surface and dimension test, non-destructive test, hydrostatic test.
Identification of the chemical composition of the metal used to manufacture the fitting. Uses PMI sensors, including X-ray fluorescence or optical emission spectrometry.
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.
Commonly used alloying elements and their effects are listed in the table given below.
| Alloying Elements | Effect on the Properties |
|---|---|
| Chromium | Increases Resistance to corrosion and oxidation. Increases hardenability and wear resistance. Increases high temperature strength. |
| Nickel | Increases hardenability. Improves toughness. Increases impact strength at low temperatures. |
| Molybdenum | Increases hardenability, high temperature hardness, and wear resistance. Enhances the effects of other alloying elements. Eliminate temper brittleness in steels. Increases high temperature strength. |
| Manganese | Increases hardenability. Combines with sulfur to reduce its adverse effects. |
| Vanadium | Increases hardenability, high temperature hardness, and wear resistance. Improves fatigue resistance. |
| Titanium | Strongest carbide former. Added to stainless steel to prevent precipitation of chromium carbide. |
| Silicon | Removes oxygen in steel making. Improves toughness. Increases hardness ability |
| Boron | Increases hardenability. Produces fine grain size. |
| Aluminum | Forms nitride in nitriding steels. Produces fine grain size in casting. Removes oxygen in steel melting. |
| Cobalt | Increases heat and wear resistance. |
| Tungsten | Increases hardness at elevated temperatures. Refines grain size. |
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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