Stainless steel heat exchanger tube is used for boiler, heat exchanger, and condenser, ASTM standards are A249 for welded tube and A213 for seamless tube, typical stainless steel grades include 304/304L, 316/316L/316Ti/316H, 321, and duplex 2205. Stainless steel has a more favorable heat transfer effect than traditional carbon steel and has a longer life span.
The heat exchanger tube is one of the elements of the heat exchanger, which is placed inside the cylinder and used for the exchange of heat between two media. It has high thermal conductivity and good isothermal properties. It is a device that can quickly transfer heat from one point to another with almost no heat loss, so it is called a heat transfer superconductor. Heat exchanger tubes can be in finned tube, threaded tube, or spiral groove tube to enhance heat transfer.
Heat Exchanger Tube Specifications
| Welded Tube | ASTM A249 ASTM A269 ASTM A789 |
|---|---|
| Seamless Tube | ASTM A213 ASTM A269 ASTM A789 |
| Grades | 304/304L, 316/316L/316Ti/316H, 321/321H 2205 / S31803, S32750, S32760 439, 410, 446 |
| Surface | Annealing Pickling Bright Annealing |
| Outside Diameter | 6.53 Mm – 127 Mm |
| Thickness | 0.5 Mm – 5 Mm |
| Tube Types | Straight Tubes U bending Tubes Finned Tubes Twisted Tubes |
| Application | Heat Exchanger, Boiler, Condenser, Cooling, Heating |
Welded Stainless Steel Heat Exchanger Tube
Welded stainless steel tube is used in heat exchanger system, annealing pickling or bright annealing finishes are available, tube welding bead should removed and grinding inside and outside to ensure a smooth surface, it is easy to clean inside heat exchanger, DONGSHANG Stainless is a welded stainless steel tube suppliers which can offer U bend tube and coil tube for various types of heat exchanger.
Welded Tube Standards
| ASTM | ASME |
|---|---|
| A-789 | SA-789 |
| B-163 | SB-163 |
| A-249, A-269 | SA-249 |
Seamless Stainless Steel Heat Exchanger Tube
Seamless stainless steel heat exchanger tube, covering kinds of stainless steel grades to meet various requirements, minimum wall thickness or average wall thickness as agreed, cold drawn and cold rolled finishing, control tolerance of outside diameter, wall thickness and length, testing, and inspection as standard should be carried out to make high-quality heat exchanger tubes.
Seamless Tube Standards
| ASTM | ASME | EN |
|---|---|---|
| A-789 | SA-789 | 10216-5 |
| B-163 B-407 | SB-163 SB-407 | 10216-5 |
| B-668 | SB-668 | 10216-5 |
| A-269 | SB-677 | 10216-5 |
| A-213 A-269 | SA-213 | 10216-5 |
Heat Exchanger Tube Materials
Austenitic Stainless Steels
| UNS | ASTM | EN Steel No. | W.-Nr |
|---|---|---|---|
| S30403/S30400 | 304L/304 | 1.4306/1.4301 | 1.4306/1.4301 |
| S31603/S31600 | 316L/316 | 1.4435/1.4436 | 1.4435/1.4436 |
| S31635 | 316Ti | 1.4571 | 1.4571 |
| S32100/S32109 | 321/321H | 1.4541/1.4940 | 1.4541/1.4878 |
Duplex Stainless Steels
| UNS | ASTM | EN No. | W.-Nr |
|---|---|---|---|
| S31500 | – | 1.4424 | 1.4417 |
| S31803/S32205 | – | 1.4462 | – |
| S32304 | – | 1.4362 | 1.4362 |
| S32707 | – | – | – |
| S32750 | – | 1.4410 | – |
High-Alloy Austenitic Stainless Steels And Nickel Alloys
| UNS | ASTM | EN Steel No. | W.-Nr |
|---|---|---|---|
| N06600 | Alloy 600 | – | 2.4816 |
| N06690 | Alloy 690 | 2.4642 | 2.4642 |
| N06625 | Alloy 625 | – | – |
| N08825 | Alloy 825 | – | 2.4858 |
| N08800 | – | 1.4558 | 1.4558 |
| N08028 | – | 1.4563 | 1.4563 |
| N08904 | – | 1.4539 | 1.4539 |
| S31254 | 254SMO | 1.4547 | (1.4529)** |
Commonly used materials include carbon steel, low alloy steel, stainless steel, copper, copper-nickel alloys, aluminum alloys, titanium, etc. In addition, there are some non-metallic materials, such as graphite, ceramics, PTFE and so on. Design should be based on the working pressure, temperature and corrosivity of the medium to choose the right material.
Stainless Steel Heat Exchanger Tube Sizes
| OD/WT (Mm) | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 | 1.2 | 1.5 | 1.65 | 2.0 | 2.11 | 2.5 | 3.0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 12.7 | • | • | • | • | • | • | • | ||||||
| 14 | • | • | • | • | • | • | • | • | • | ||||
| 15 | • | • | • | • | • | • | • | • | • | ||||
| 16 | • | • | • | • | • | • | • | • | • | ||||
| 19.1 | • | • | • | • | • | • | • | • | • | • | • | ||
| 20 | • | • | • | • | • | • | • | • | • | • | • | ||
| 22 | • | • | • | • | • | • | • | • | • | • | • | ||
| 23 | • | • | • | • | • | • | • | • | • | • | • | ||
| 25.4 | • | • | • | • | • | • | • | • | • | • | • | • | |
| 28 | • | • | • | • | • | • | • | • | • | • | • | • | |
| 30 | • | • | • | • | • | • | • | • | • | • | • | • | |
| 31.8 | • | • | • | • | • | • | • | • | • | • | • | • | |
| 34 | • | • | • | • | • | • | • | • | • | • | • | • | |
| 35 | • | • | • | • | • | • | • | • | • | • | • | ||
| 38.1 | • | • | • | • | • | • | • | • | • | • | • | ||
| 40 | • | • | • | • | • | • | • | • | • | • | |||
| 42.2 | • | • | • | • | • | • | • | • | • | • | |||
| 44.5 | • | • | • | • | • | • | • | • | • | • | |||
| 50.8 | • | • | • | • | • | • | • | • | • | ||||
| 60.3 | • | • | • | • | • | • | • | • | |||||
| 63.5 | • | • | • | • | • | • | • | • | |||||
| 76.2 | • | • | • | • | • | • | • | ||||||
| 88.9 | • | • | • | • | • | • | • | ||||||
| 101.6 | • | • | • | • | • | • | • |
Heat Exchanger Tube Manufacturer
We manufacture and supply heat exchanger tubes in sizes ranging from 6 mm to 76 mm OD. All standard outside diameters and wall thickness for heat exchanger tubing are covered with maximum lengths of 30 meters. Tubes can be supplied in straight or U-bends. Special sizes can be made on request.
Dongshang holds extensive equipment such as extrusion presses, Pilger machines, straightening machines, degreasing facilities, solution & bright annealing furnaces, stabilization furnaces and drawing equipment.
The Manufacturing methods employed at the mill’s main production units reflect the most advanced technologies. Production of seamless and welded stainless steel tubes is carried out according to all common international delivery and tolerance standards.
Heat Exchanger Tube Standard Specifications
- ASTM A 213- Standard specification for seamless, ferritic and austenitic alloy-steel boiler, superheater and heat exchanger tubes.
- ASTM A249, Standard specification for welded austenitic steel boiler, superheater, heat-exchanger, and condenser tubes
- ASTM A789- Standard specification for seamless, duplex stainless steel heat exchanger tubing.
- ASTM B161- Nickel seamless pipes and tubes.
- ASTM B163- specification for seamless nickel and nickel alloy condenser and heat exchanger tubing.
- ASTM B167-Nickel-Chromium-Iron alloys and Nickel-Chromium Cobalt-Molybdenum alloy pipes and tubes.
- ASTM B668-standard specification for UNS08028 seamless pipes and tubes.
- EN 10216-5 TC-1 & TC 2, DIN Standards.
Grades Available
Heat exchanger tubes are available in a variety of metals including steel, copper, brass, 70-30 copper-nickel, aluminum bronze, aluminum, and stainless steel, stainless steel grades are available as follows:
- 304/304L – 1.4301/1.4307
- 316/316L – 1.4401/1.4404
- 316Ti – 1.4571
- 321/321H – 1.4541 -1.4878
- 347/347H – 1.4550
- 310/S/H -1.4845
- 253 MA – UNS S30815 – 1.4835
- UNS S31803/2205 -1.4462
- UNS S32750 – 1.4410
- UNS S32760 – 1.4501
- 6Mo – 1.4547 – UNS S31254
- 904L – 1.4539
- ALLOY 825 – 2.4858
- ALLOY 20 – 2.4660
OTHER GRADES AVAILABLE UPON REQUEST
Standard And Additional Tests In House
- NACE MR0175 – NACE MR 0103 – EN ISO 15156
- Intergranular corrosion, ISO 3651-2 METHOD A – ASTM A262 PRACTICE E – MIL P24691/3
- 100% PMI tested
- Material hydraulically tested according to A999 par22.2
- Cold-finished material eddy current tested according to E426
- Mechanical (Tensile/Hardness/Flattening/Flaring/Bend), Chemical analysis,
- Hydrostatic test
- ASME Boiler and Pressure Vessel Code, Comprehensive standard for the design, fabrication, and inspection of boilers, pressure vessels, and related equipment.
- TEMA, Tubular Exchanger Manufacturers Association standards for shell-and-tube heat exchangers.
Heat Exchanger Tube Sizes
Heat exchanger tubes are obtainable in several wall thicknesses defined by the Birmingham Wire Gauge (B.W.G.), which is usually referred to as the B.W.G. or gauge of the tube. The outside diameter of heat-exchanger tubes is the actual outside diameter within a very strict tolerance.
For the corresponding Tube OD and material, select the B.W.G (Birmingham Wire Gauge) number. For Example, if you select the tube material as carbon steel and tube OD as 1 inch then the B.W.G number will be either 14 or 12. Tube diameters in the range 1/4 in. (6.35 mm) to 2 in. (50 mm) are used. The smaller diameters 5/8 to 1 in. (16 to 25 mm) are preferred for most duties, as they will be more compact resulting in cost economy (cheaper exchangers). Larger tubes are easier to clean by mechanical methods and would be selected for heavily fouling fluids. The tube thickness (gauge) is selected to withstand the internal pressure and give an adequate corrosion allowance, the most commonly used tube diameters are ¾ inch and 1 inch.
The use of small tube diameter can make the heat transfer area per unit volume increase, compact structure, metal consumption reduction, and heat transfer coefficient increase. It is estimated that by changing the heat exchanger tube of the same diameter heat exchanger from Φ25mm to Φ19mm, the heat transfer area can be increased by about 40%, saving more than 20% of metal. However, small pipe diameter fluid resistance is inconvenient to clean, easy to scale, and clogging. Generally, large-diameter tubes are used for viscous or dirty fluids and small-diameter tubes are used for cleaner fluids.
After choosing the tube diameter and the tube thickness, we must choose the tube length according to TEMA standards. While choosing we must consider the availability of the space with the client. If nothing is specified about the length of the tube by the client then choose the tube length according to TEMA standards. For a given surface area, the use of longer tubes will reduce the shell diameter, which will generally result in a lower-cost exchanger, particularly for high shell pressures.
U Bend Stainless Steel Tubes are manufactured for heat exchangers commonly according to ASTM/ASME A688 standard, after U bend (cold forming), heat treatment of the bending portion may be required.
Heat Exchanger
The heat exchanger is a specialized device that assists in the transfer of heat from one fluid to the other. In some cases, a solid wall may separate the fluids and prevent them from mixing. In other designs, the fluids may be in direct contact with each other. In the most efficient heat exchangers, the surface area of the wall between the fluids is maximized while simultaneously minimizing the fluid flow resistance. Fins or corrugations are sometimes used with the wall in order to increase the surface area and induce turbulence.
Heat exchangers are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment.
Flow Arrangements
There are three primary flow arrangements with heat exchangers: counter-flow, parallel-flow, and cross-flow. In the counter-flow exchanger, the fluids enter the exchanger from opposite sides. This is the most efficient design because it transfers the greatest amount of heat. In the parallel-flow version, the fluids come in from the same end and move parallel to each other as they flow to the other side. The cross-flow heat exchanger perpendicularly moves the fluids.
Arrangements of the heat transfer tube should be made in the entire heat exchanger circular cross-section of the uniform and compact distribution, in the tube sheet as much as possible, which not only can get the maximum area of heat transfer, but also reduce the phenomenon of short-circuiting of the fluid around the tube bundles, and also to consider the nature of the fluid, the structure of the tube box and the processing of manufacturing and other aspects of the problem.
Heat Exchanger Types
There are four different types of heat exchangers: shell and tube heat exchangers, double-tube heat exchangers, tube-in-tube heat exchangers and plate heat exchangers.
Shell and Tube Heat Exchanger
Shell and tube heat exchanger is the most typical type of design. This has multiple finned tubes. One of the fluids runs through the tubes while the other fluid runs over them, causing it to be heated or cooled. A shell and tube exchanger consists of a number of tubes mounted inside a cylindrical shell. Two fluids can exchange heat, one fluid flows over the outside of the tubes while the second fluid flows through the tubes. The fluids can be single or two-phase and can flow in a parallel or a cross/counter flow arrangement.
Structure
Its basic structure includes components such as the shell, tube bundle, tube sheet, head (also known as end cap), and folding plate used to support the tube bundle and guide the fluid flow.
Characteristics
Tube heat exchanger has the characteristics of a sturdy structure, flexible operation, wide adaptability, and ease of cleaning and overhaul. Bote salt wastewater evaporator or production of salt solution evaporator often uses stainless steel or titanium material tube heat exchanger (or shell and tube heat exchanger), belongs to the inter-wall heat exchanger, used for heating is called heater, used for cooling is called condenser.
Connection of Tube and Tube Sheet
The connection of tube and tube sheet is the main problem in the manufacture of shell and tube heat exchanger. Connection methods include expansion and welding.
As the expansion joint relies on the deformation of the tube to achieve sealing and compression of a mechanical connection method, when the temperature rises, the rigidity of the material decreases, and the thermal expansion stress increases, which may cause the joints to fall off or loosen, and leakage occurs. Therefore, at high temperatures, it is not advisable to use expansion joints. In recent years, the proportion of welding method is increasing, it is generally believed that welding is more than expansion to ensure tightness. For carbon steel or low alloy steel, temperature above 300 ℃, most of the welding connections. For high-temperature and high-pressure pipes, welding with expansion is now widely used. This method can improve the fatigue resistance of the joint and can eliminate stress corrosion and interstitial corrosion, thus extending the service life of the joint.
Double-tube heat exchangers
Double tube heat exchangers employ the simplest heat exchanger design and configuration which consists of two or more concentric, cylindrical pipes or tubes, there are two pipes where one is built inside the other, a smaller tube within a larger tube structure. One fluid flows through the inner pipe while the second fluid flows around the first fluid in the outer pipe. This type of heat exchanger is known for being the most basic and affordable of all. Its size makes it ideal for tight spaces, allowing for some extra flexibility in the layout of the manufacturing process.
Tube in tube heat exchanger
Tube in tube heat exchanger is comprised of two tubes, one for each fluid. However, the tubes are coiled together to form an outside and inside pattern. The application for a tube-in-tube design can get fairly creative. Since the tubes are coiled together, most designs for this type are compact. Applications for a tube-in-tube heat exchanger center around high temperature and high pressure. Since it runs at a higher output, a tube-in-tube heat exchanger tends to have greater efficiency.
Plate heat exchangers
Plate heat exchangers are constructed of several thin, corrugated plates bundled together, the fluid flows through baffles. This causes the fluids to be separated by plates with a large surface area. This type of exchanger is typically more efficient than the shell and tube design.
Some variations of type include pillow plate heat exchangers, plate and frame, plate and shell, and spiral plate heat exchangers.
Heat Exchanger Applications
Heat exchanger is a device used to transfer heat between a solid object and a fluid, or between two or more fluids at different temperatures, transfer heating from higher temperature fluid to lower temperature object to make fluid temperature to specified requirement, for stainless steel grades, there are shell and tube heat exchanger, plate heat exchangers, plate and shell heat exchanger and other heat exchanger, tube heat exchanger consists of a number of tubes inside bundle and sheet, widely used in many industries.
- space heating
- refrigeration
- air conditioning
- power stations
- chemical plants
- petrochemical plants
- petroleum refineries
- natural-gas processing
- wine and beer-making
The use of heat exchangers
- Heater: The heater is used to heat the fluid to the desired temperature, and the heated fluid does not undergo phase change during the heating process.
- Preheater: Preheater is used to preheat the fluid to improve the efficiency of the whole process unit.
- Superheater: The superheater is used to heat the saturated vapour to a superheated state.
- Evaporator: The evaporator is used to heat the fluid to evaporate and vaporize it.
- Reboiler: Reboiler is a special equipment for the distillation process, which is used to heat the liquid that has been condensed so that it is re-heated and vaporized.
- Cooler, rcooler is used to cool the fluid, so that it reaches the required temperature.
- Condenser: the condenser is used to condense the saturated vapour, so that the release of latent heat and condensation liquefaction.