DELLOK Carbon Steel Welded Nailhead Tube
About Us
DELLOK (YONGHUI RADIATING PIPE MANUFACTURING CO.,LTD.) was established in 2002, which is located in Jiangsu, China. After many years of development, the company now has 66 million yuan in fixed assets, more than 200 employees, and 33 technical staffs. We have 4 aluminum processing production lines, with the annual processing capacity of more than 20,000 tons; And we have 5 tube-drawing production lines; 47 fintube production lines, 1 imported production line from American with the brand of McElroy , with the annual production capacity of 12 million meters the above. Quality is the theme of eternal pursuit of winner -Production workshop- Meticulous works, standardized management system and systematic quality assurance are Dellok(YONGHUI)'s best commitment to quality. In Dellok(YONGHUI), the quality control is not only the detection of the final process, but throughout the entire production process. We implement a set of quality control and assurance systems. Each batch of pipes is sampled and tested, and records are kept as a quality guarantee for the final product.
Studded Tube or called Nailhead tube
Steel studded tubes are used instead of Fin Tube for heat transfer in the processing industries, generally in furnaces, gas turbines, fired heaters and furnace applictions where the surface is exposed to a very corrosive environment and where very dirty gas streams require frequent or aggressive cleaning.
The steel studs(Welded Stainless Tube) are automatically resistance welded to the tube, producing high quality forge welds. The welding process enables the combination of any grades for studs and tube(Black Welded Pipe): carbon, low alloy, stainless steels and high nickel alloys. Alloy steel pipes are stress-relieved after studding, according to the relevant specifications for the class and grade of steel used.
Because of their relative easy of cleaning, studded tube(Stainless Steel Welded Tube) or nail head pipes(Weld Galvanized Pipe) are used in furnaces and fired heaters as an alternative to high frequency welded finned tubes wherever the process application is such that heavy fouling of the external surface may occur.
Product Specification
| Tube O.D |
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| Tube Wall Thk. | 3.5~28.6 (mm) | ||
| Tube Length | ≤25,000 (mm) | ||
| Stud Height | 10~35 (mm) | ||
| Stud Pitch | 8~30 (mm) | ||
Test of Stud Pitch:studded tube
Welding tests are carried out as a matter of course to ensure the effectiveness of the stud to pipe bond. Heat treatment of the completed studded tube is carried out where necessary. Should fouling eventually reduce the process performance of the equipment, the studded surface can be
cleaned efficiently by shot blasting without damage to the materials.
An electric current is applied by connect on the stud and tube and theresistance in this circuit produces the heat necessary for welding. Maximum resistance and therefore maximum heating occurs at the interface Between the Stud and the tube. Pressure to forge the Stud and the tube together at the point of maximum heating is applied by various forms of tooling. These resistance welding processes produce a strong metallurgical bond between the stud and the tube while minimizing the heat affected zone (HAZ) in the tube. The use of pressure to forge the fin and the tube together helps to minimize the heat input necessary to make the weld. This Product is used in Fired Heaters under Very High Pressure & Temperature mainly in Petroleum refineries.
STUDDED TUBE
Studded tubes are used as substitution of finned tubes for heat transfer in the petrochemical industry, generally in fired heaters and boilers where the surface is exposed to a very corrosive environment and where very dirty soot formation require frequent or aggressive cleaning.
FABRICATION PROCESS
The studs are automatically welded to the tube by electric resistance welding machine. The welding process is controlled by PLC program, stepping motor, indexing adopt brake motor. All the welding parameters such as number of studs, pitch, compensation coefficient etc. are input via human machine interface(HMI), Product quality could be guaranteed by the settings according to the process requirements.
The automatic stud feeder was developed by our engineers combining both our large experience manufacturing extended surface and the most modern control technology available in the market. The technology has benefited us with more efficient production and consistent welding quality.
APPLICAITONS
Murphy's studded tubes are generally installed in the convection sections and boilers where the surface is exposed to a severe operating case of dirty flue gas.
Frequently Asked Questions (FAQ) About Studded Tubes:
1. What is a Studded Tube?
Studded tubes are a type of metal tubes. These tubes have studs welded onto the metal tube.
These studs are arranged in a specific formation throughout the length of the tube.
They are often used in boilers and refineries. As they increase the surface area for higher heat transfer they are used for reheating.
2. Why use studded tubes?
The heat exchange efficiency is equivalent to 2-3 times that of the bare pipe.
Easier cleaning especially for operating cases with very dirty flue gas produced by burning heavy oil, diesel or residual oil.
To increase the film heat transfer coefficient of flue gas to the furnace tube.
Increase efficiency in the process of heat recovery and direct flame hostile atmospheres.
Reduce the amount of bare pipes used in these processes. (Heat transfer surface of one studded pipe is equivalent to surface of 4 to 10 bare pipes). Stud Pipe's ideal for processes applications where dirty fuels are used and harsh environments in terms of temperature and/or corrosion.
Studded fin tube is a standard frequency electric-resistance-welded studded type surface. It is normally manufactured with round carbon steed studs on carbon, alloy or stainless steel tubes with diameters from 1.5" to 12.75".
3. What are the important factors for high frequency welding?
The four most important factors / process parameters influence High frequency welding are
Electrical power
Pressure applied
Welding time
Cooling time
Finding the optimal process parameters will depend on your specific equipment, the materials involved and the specific geometries including thickness and area to be welded. Achieving optimal results is often an experimental process guided by experience. As a guiding rule, the thicker material and focus on short weld times you need, the stronger electrical power / HF generator you need.
4. What is High Frequency welding?
High frequency welding (often abbreviated HF welding or RF welding) is a manufacturing process where two plastic parts are welded together using an electromagnetic field. The resulting join can be very strong – often close to the original strength of the materials joined. In some scenarios the weld can be even stronger than the original materials.
Using a high frequency electromagnetic field, the material is heated and pressure added to melt and fuse the two materials together. No outside heart is applied. Instead the heat is generated within the materials. During cooling (under continued pressure), the materials are fused together and a weld has been created. This results in a very strong bond between the two parts.
5. Where are Studded Tubes used?
Studded tubes are used instead of finned tubes for heat transfer in the processing industries, generally in furnaces, gas turbines, fired heaters and furnace applications where the surface is exposed to a very corrosive environment and where very dirty gas streams require frequent or aggressive cleaning.
6. How do you control your quality?
We always put quality as the most important thing for customers, and we control the quality from raw material inspection, production checking to water pressure test and strength test. Also the third party can be authorized to check.
Incoming inspection report for bare tube & strip.
Mill test certification for bare tube
Mill test certification for fin
Mill test certification for finned tube
Finned tubes dimension & visual inspection reports
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25~273 (mm) |
