Alloy steel U tubes

Alloy steel U tubes

Alloy steel U tubes are essential components in heat exchangers and condenser systems, known for their versatility and ability to efficiently transfer heat in various industrial processes.

Alloy steel U tubes are typically constructed from materials containing varying proportions of alloying elements like chromium (Cr), molybdenum (Mo), nickel (Ni), and others. These alloys offer exceptional heat resistance, corrosion resistance, and mechanical strength.

Alloy Steel U-tube heat exchanger tubes are bent into a U-shaped tube, the fluid inlet and outlet were installed in the same side on both sides of the head with partitions into two rooms, each tube is free to expand and retract to solve the heat Compensation problem.

The U tube is an important part of the U tube heat exchanger.

The main structure of the U type tube heat exchanger includes the tube box, the barrel, the head, the heat exchange tube, the nozzle, the baffle plate, the punching plate and the guide tube, the short circuit structure, the support and other accessories.

Alloy Steel U tubes used for heat transfer tubes is usually used for heat transfer tubes and ordinary cold drawn tubes. The former is suitable for non phase transition heat transfer and vibration prone situations, and the latter is suitable for reboiling, condensing heat transfer and non vibration general situations.

Alloy Steel U tubes has a variety of forms, smooth tube is the most traditional form, because it has the advantages of easy manufacturing and low unit length cost, which is the most common in the current application. The pipe should be able to withstand certain temperature and stress. When the tube and shell side fluid are corrosive, the pipe should also have corrosion resistance.

The material of Alloy Steel U tubes:T5, T11, T12, T22, T9, T91, etc.

U Tubes for Heat Transfer

The U-shaped configuration of these tubes significantly enhances their heat transfer capabilities. This design increases the surface area available for heat exchange, resulting in improved efficiency in heat exchangers and condenser systems.


Alloy steel U tubes find extensive use across diverse industries, including:

All processes are carried out according to technical standards: TEMA “R” for heat exchanger tubes and UNI EN 12952-5 for boiler plants.

U-Bent Tubes are tested at 100%

U-Bent Tubes are tested at 100%

Wooden Cases for U-Bent Tubes

Wooden Cases for U-Bent Tubes

Technical specification – U-Bent Tubes

U-bent tubes are manufactured according to the technical specifications requested by customers:

Outside diameter
6 ÷ 63.5 mm
¼”÷ 2 ½”
Maximum overall length
1 ÷ 28 m
3 ÷ 92 ft

Bending radius (minimum)

1,5 × tube diameter 

Bending radius (maximum)

1500 mm | 4 ft

What are alloy steel tubes?

Alloy steel tubes are made from high-quality carbon steel, alloy structural steel, and stainless steel heat-resistant steel. These tubes are hot rolled or cold drawn. Alloy steel tubes are ideal for industrial applications because they have added alloying elements like manganese and nickel. These elements improve the strength, hardness, and toughness of the metal.

Alloy steel tubes are used in process areas where carbon steel has limitations, such as high-temperature service. They are also used for power generating equipment, chemical processing equipment, automotive applications, and structural components.

Alloy steel tubes are manufactured using two basic technologies:

U bend tube packing

Standard for Alloy steel U tubes

The semi-finished product for U bend tubes are heat exchanger tubes, manufactured and supplied according to DIN 28180 and ASTM A179.

Tubes for heat exchangers are made of steel according to:

Standard Application
ASTM A179 Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
ASTM A192 Seamless Carbon Steel Boiler Tubes for High-Pressure Service
ASTM A210 Seamless Medium-Carbon Steel Boiler and Superheater Tubes
ASTM A213 seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
ASTM A334 Seamless Steel Pipe for Low-Temperature Service and other Applications with Required Notch Toughness
JIS G3461/2 carbon steel tubes used for heat exchange in boilers, heat exchangers, condensers, and similar equipment
EN10216-1/2 specified the standard of cold processed precision steel tubes in a wide range of sizes
DIN17175 seamless tubes for high-pressure and high-temperature applications, specifically for boilers and heat exchangers

Chemical Composition and Mechanical Properties (Part)

Standard Grade Chemical Components (%) Mechanical Properties
C Si Mn P S Mo Cr V T.S.  (Mpa) Y.S.  (Mpa) E.L.
ASME SA179 SA179 0.06-0.18 / 0.27-0.63 ≤0.035 ≤0.035 / / / ≥325 ≥180 ≥35 ≤72
ASME SA192 SA192 0.06-0.18 ≤0.25 0.27-0.63 ≤0.035 ≤0.035 / / / ≥325 ≥180 ≥35 ≤77
ASME SA210 A1 ≤0.27 ≥0.10 ≤0.93 ≤0.035 ≤0.035 / / / ≥415 ≥255 ≥30 ≤79
C ≤0.35 ≥0.10 0.29-1.06 ≤0.035 ≤0.035 / / / ≥485 ≥275 ≥30 ≤89
ASTM A333 /A334 GR.1 ≤0.30 / 0.4-1.06 ≤0.025 ≤0.025 / / / ≥380 ≥205 ≥35 -45°
GR.6 ≤0.30 ≥0.10 0.29-1.06 ≤0.025 ≤0.025 / / / ≥415 ≥240 ≥30 -45°
GR.8 ≤0.13 0.13-0.32 ≤0.90 ≤0.025 ≤0.025 / / 8.40-9.60 ≥690 ≥515 ≥22 -195°

U bend tubes for heat exchangers applied mostly in oil and gas plants, chemical and petrochemical plants, refineries, power plants and renewable energy plants. Low fin tubes can be supplied in the form of U bends.

U-Bend Fabrication Tolerances

U-bend tubes are widely used in heat-exchanger systems. Heat-exchanger equipment on the basis of seamless stainless U-tubes is essential in strategically important and critical fields — nuclear and petrochemical machine building.

U bend tube drawing
Item Condition (when) Tolercance
 Ovality   Nominal bend radius ≤ 2 x nominal OD less than or equal to 12%
2 x nominal OD < Nominal bend radius ≤ 4 x nominal OD less than or equal to 10%
Nominal bend radius > 4 x nominal OD  less than or equal to 5%
Nominal bend radius ≤ 2 x nominal OD 0.75 x nominal wall
Mimimum wall thickness   2 x nominal OD < Nominal bend radius ≤ 4 x nominal OD 0.8 x nominal wall
Nominal bend radius > 4 x nominal OD 0.9 x nominal wall
Nominal bend radius ≤ 8" (200mm) +/-3/64"(1mm)
Bending Radius  8" (200mm) < Nominal bend radius ≤ 16" (400mm) +/-1/16"(1mm)
Nominal bend radius >16" (400mm) +/-5/64"(1mm)
Disrance between legs   Max 1/16"(1.5mm)
Wall thinning of bending area   Max 17%
Difference between leg lengths at the ends Leg length ≤ 16' (4.88m) +1/8"(3mm)
Leg length > 16' (4.88m) +3/16"(5mm)
Deviation from plane of bend   ≤ 3/16"(1.5mm)
Flattening on bend   ≤ 10% nominal diameter
Straight leg length ≤5m +1/8"(3mm)
>5m +3/16(5mm)
Total tube length including radius ≤6m +3/16(5mm)
>6m +5/16"(8mm)

Packing for U bend Tubes

We packs all U Tube bundles in bespoke wooden boxes and separate all U Tubes of different radii using finger pallets to facilitate easy assembly of bundles on receipt.

Wooden Cases for U-Bent Tubes

Wooden Cases for U-Bent Tubes

U bend tube packing
U bend tube packing
U bend tube packing
U bend tube packing
U bend tube packing

Any type of packing is available according to customer need to worldwide destinations.

【H】 Ceramic lined pipe

Ceramic lined pipe is made through self-propagating high-temperature synthesis (SHS) technique.

【H】 Cast basalt lined steel pipe

Cast basalt lined steel pipe is composed by lined with cast basalt pipe, outside steel pipe and cement mortar filling between the two layers.

【H】 Ceramic Tile Lined Pipes

Ceramic tile lined pipes have very uniform coating of specially formulated ceramic material that is affixed to the inner of the pipe.

【H】 Rare earth alloy wear-resistant pipe

The material of the rare earth alloy wear-resistant pipe is ZG40CrMnMoNiSiRe, which is also the grade of rare earth alloy steel.

【H】 Tubes Erosion Shields

Tubes Erosion Shields are used to protect boiler tubing from the highly erosive effects of high temperatures and pressures thereby greatly extending tube life.

【H】 ASTM A213 T91 Alloy Tube

The ASTM A213 T91 seamless tubes are primarily used for boiler, superheater, and heat-exchanger.

Ni-Hard Wearback Pipes Ni-Hard Wearback Pipes