U-bend tubes

Each U bend tube of our range is rigorously quality checked by our team of talented professionals on every stage of production to deliver the clients defect free best quality products.

Tubes for heat exchangers are made of steel according to:

U bend dimension capablity

Tube OD Tube thickness Bending Radius U tube straight “leg” length Straight tube before U bending
Min. 12,7mm / Max. 31,75mm Min. 0,70mm / Max. 4,19mm Min. 1,5 x OD / Max. 1250mm Max. 12500mm Max. 27000mm

Measuring, Cutting, Deburring and Cleaning

We bring forth an exclusive range of U-bend tubes, which are known for their superior quality and excellent functionality.

After U bend (cold forming), heat treatment of bending portion may be required. Temperature is controlled through the entire heat treated area by fixed and portable infrared pyrometers.

Dimensional controls on U bend tube
  • Hydrostatic Test
  • Air Underwater Test
  • Pulsating Pressure Test
  • Dye Penetrant Test
  • Magnetoscopic test
  • Dye penetrant of ‘U’ bend area
  • PMI testing
  • Heat Treatment

All tubes are cut to the specified leg lenghts, ends deburred and the bores are internally cleaned with dried air.

Standard for U bend Tubes

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

U-bend or U-shape

At present Sunny Steel has purchased the equipment for production of the following product range:

Carbon & Alloy Ferrite Austenite Duplex

Packing

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

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

Usage

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 tubes for heat exchangers applied mostly in Oil & Gas plants, Chemical & Petrochemical plants, Refineries, Power plants, Renewable energy plants."
  • Object medium: 10% sodium
  • hydroxide+5% sodium hypochlorite
  • Shell Diameter: ø 800
  • Working Pressure: 1.5mpa
  • Working Temperature: 40º C-90º C
  • Heat Exchange Surface Area: 100M2
  • Material: Gr1\Gr2

ASTM A213 ASME SA213 Seamless Alloy Carbon Steel Heat Exchanger U Tubes for Boilers

SA213 long steel tubes, make to U bend tubes for boilers and heat exchangers.

With strong wood structure box packing by containers loading and shipping.

ASTM A556M-88/ASME SA556 Seamless cold drawn steel feedwater heater tubes 1

(ASTM A 556 ]M - 88 / ASME 556 /ASTMA556M-88/ASME556)

U-tube heat exchanger
U-tube heat exchanger

ASTM A556 is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

Feedwater Heater Tubes
Standard:ASME SA556 Chemical Compostion
Grade C % Si % Mn % P % S %
B2 0.27 max 0.10 min 0.29-0.93 0.030 max 0.030 max
C2 0.30 max 0.10 min 0.29-1.06 0.030 max 0.030 max


Mechanical Properties

Grade Tensile Strength MPA Yield Strength MPA Hardness HRB
B2 410 min 260 min 79 min
C2 480 min 280 min 89 min

Each U bend tube of our range is rigorously quality checked by our team of talented professionals on every stage of production to deliver the clients defect free best quality products. These U bend tubes can be custom designed in various diameters as per the requirements of our clients.

U-Bend Fabrication Tolerances

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

Features :
  • 'U' bending is done by cold working process.
  • 'U' bending is done to the required radius as per customer drawings.
  • The bend portion and six inch leg is stress relieved by resistance heating.
  • Inert gas (Argon) is passed through it at the required flow rate to avoid oxidation in ID.
  • The radius is checked for its OD and wall thinning with the recommended specification.
  • The physical properties and micro-structure is checked at three different position.
  • Visual inspection for waviness and cracks is done with Dye Penetrant Test.
  • Each tube is then hydro tested at the recommended pressure to check for leakage.
  • Cotton ball test is done to check the ID cleanliness of the tube.
  • Thereafter pickled, dried, marked and packed.
Item Condition (when) Tolercance
  Nominal bend radius ≤ 2 x nominal OD less than or equal to 12%
Ovality 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)

Standards usually required to establish U bend tube tolerances:

  • ASTM A556/556M
  • ASTM B395 / B395M
  • ASTM A688/688M
  • ASTM A803/803M
  • DIN 28179

Materials - U Bend Tube

‘U’ bends are produced, controlled and measured fully in accordance with relevant standards.

Carbon Steel SA 179 / A 179
Carbon Steel SA 210 / A 210
Carbon Steel SA 334 / A 334
Stainless Steel SA 213 / A 213
Duplex Stainless Steel SA 789 / A 789
Copper & Cu Alloys SB 111 / B 111
Titanium & Ti Alloys SB 338 / B 338

 



Tech & Service of Seamless pipe

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.

How to make seamless pipe(seamless pipe process)?
Hot Piercing Workshop
Piercing process
The cross roll piercing and pilger rolling process in the size range from approx. 250 to 660 mm outside diameter.
Precision cold drawn steel tube production process
Pipe weld cracks
often follow different mechanisms can be divided into two types of thermal cracking and cold cracking.
How to calculate a steel pipe and tube theoretic weight
Calculate a steel pipe?
Pipe fittings are necessary to join together pipes, or to change the direction of an existing pipe.
Pipe beveling
Pipe beveling is the process where an angle is formed between the edge of the end of a pipe or tube and a plane perpendicular to the surface.
Steel pipe cutting machine
Pipe cutting
Cutting tools have a grinding wheel piece cutting machine (also known as toothless saw), hand saw, cutter and other hand tools.
How to calculate a steel pipe and tube theoretic weight
Packing the steel pipes
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.

Condition on delivery:

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.
 


About Sunny Steel

Our team are highly trained and experienced in servicing and producing all types of steel supplies. Whether you've got a large construction project, or need parts for industrial machinery, our team of steel fabrication consultants will ensure that your project is provided with the parts you need, when you need them.

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