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Steel Tube

U Bend Steel Tubing

U-bend Heat Exchanger Tubes (U-bend or U-shape) ASTM A556M-88/ASME SA556 Seamless cold drawn steel feedwater heater tubes (ASTM A 556 ]M - 88 / ASME 556 /ASTMA556M-88/ASME556) ASTM A556 is a brief summary of the referenced standard. It is informational only and not an official part of the......
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U-bend Heat Exchanger Tubes (U-bend or U-shape)

ASTM A556M-88/ASME SA556 Seamless cold drawn steel feedwater heater tubes (ASTM A 556 ]M - 88 / ASME 556 /ASTMA556M-88/ASME556)

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.

he tubing sizes covered shall be 5/8 to 1 2/4-in. [15.9 to 31.8-mm] outside diameter, inclusive, with minimum wall thicknesses equal to or greater than 0.045 in. [1.1 mm].

 

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.

 

Application: Boilers, heat exchangers, super heaters, condensers

Production Standard, Grade, Steel No:

ASTM A688/A688M-Welded Austentic Steel Feedwater Heater Tubes.

ASTM A 312/213/269,DIN 17458/2462,BS3605/1,JIS, ASME SA556G3429/3459,ISO1129/2037/9329,GB/T14975/14976/13296 and so on.

 

Material:

TP304,TP304L,TP316,TP316L,TP321,TP310S,TP347H,TP316Ti, Carbon steel,alloys and so on.

 

Proces:

The removal of beads is done as per standard specifications.

Bead is cold worked.

It is brought in level with the base metal.

Before heat treatment on tube mill, bead rolling is made in-line.

This will help in recrystallization of weld structure.

The weld structure will also homogenize faster in annealing process.

Length: unbending length or fix length

 

Mill test certificate: according to EN 10204 3.2

Packing: Wooden cases, bundle or plastic bags, plywood boxes

Oil-dip, Varnish, Passivation, Phosphating, Shot Blasting.

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.

 

'U' Bend Stainless Steel Tubes are manufactured in our plant as per the customer requirements. Bends can be Heat Treated in accordance with Clients' requirements followed by hydrostatic testing and dye penetrant testing if required.

 

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

 

U-tube heat exchangers Designed for high temperature applications, especially steam condensing or hot oil systems. Thïs model is selected when differential expansion makes a fixed tube sheet exchanger unsuitable and when conditions preclude a floating head type (HPF) selection.

 

Surface condition Finished U-tubes shall be free of scale, without scratches after bending

U Bend Tubes Drawing Dimensional tolerances U tubes acc. to TEMA R.C.B.

1) Length of straight part -0/+5 mm

Flattening (also called “ovality”) at the bend shall not exceed 10% of the nominal tube outside diameter.

Wall thickness in bending part acc. to TEMA R.C.B 2.31

2) Minimum tube wall thickness in the bend part (T min)T(min) ≥ (SW × (2×R + D))/( 2× (R+D)

where: SW is smallest wall thickness

D Nominal outside diameter

R radius

3)Radius tolerance

1) for R 100 mm +/- 3 mm

2) for R ≥ 100 mm +/- 5 mm

4). Straightness tolerance max. 1,5 mm per 1 m

U-Tube ends: plain, vertically cut to the tube axis


Tubes OD in mm can be bent upon agreement: 15.8 16.0 17.0 18.0 19.05 20.0 21.3 25.4 26.7 31.8 32.0 38.1mm

Initial Length

Maximum lengths of 27000mm can be supplied on request

Bending radius

Minimum: 1.5×OD

Maximum: 1500 mm

The dimensions for heat exchanger tubes in special grades may differ from the above,please contact us.


Our Tube-bending production line, installed at 2007, will allow to produce U-tubes as per standards:

1. ASTM A688/A688M-15 Specification for Seamless and Welded Austenitic Stainless Steel Feedwater Heater Tubes

2. ASTM A803/A803M-12 Standard Specification for Seamless and Welded Ferritic Stainless Steel Feedwater Heater Tubes

3. ASTM A556/A556M-12 Standard Specification for Seamless Cold-Drawn Carbon Steel Feedwater Heater Tubes


Main Testing Terms and Procedure:

1. Heat Treatment and Solution Annealing / Bright Annealing

2. Cutting to required length and deburring;

3. Chemical Composition Analysis Test With 100% PMI and One tube from each heat by Direct Reading Spectrometer

4. Visual Test and Endoscope Test for Surface Quality Test

5. 100% Hydrostatic Test and 100% Eddy Current Test

6. Ultrasonic Test subject to the MPS (Material Purchase Specification)

7. Mechanical Tests includes Tension Test, Flattening Test, Flaring Test, Hardness Test

8. Impact Test subject to Standard request

9. Grain Size Test and Intergranular Corrosion Test

10. Ultrasoic measuring of Wall Thickness

11. Stress Relieve Annealing on U bend Parts after bending

 

Other details:

a. All tubes are cut to the specified leg lengths and internally cleaned with air, ends are deburred.

b. Before packing, both ends of U-bends are capped with plastic caps.

c. Vertical separators for each radius.

d. Packing lists, covered with plastic, are placed on each plywood case for easy identification of order details, including exact list of radius and lengths inside.

 

Heat Exchanger tubes

Tubing that is generally used in TEMA sizes is made from low carbon steel, copper, Admiralty, Copper-Nickel, stainless steel, Hastalloy, Inconel, titanium and a few others. It is common to use tubing from 5/8" to 1-1/2" in these designs.Tubes are either generally drawn and seamless or welded. High quality ERW (electro-resistance welded) tubes exhibit superior grain structure at the weld. Extruded tube with low fins and interior rifling is specified for certain applications. Surface enhancements are used to increase the available metal surface or aid in fluid turbulence, thereby increasing the effective Heat Transfer rate. Finned tubing is recommended when the shell side fluid has a substantially lower Heat Transfer coefficient than the tube side fluid. Finned tubing has an outside diameter in the finned area slightly under the unfinned, or landing area for the tube sheets. This is to allow assembly by sliding the tubes through the baffles and tube supports while minimizing fluid bypass.U-tube designs are specified when the thermal difference of the fluids and flows would result in excessive thermal expansion of the tubes. U-tube bundles do not have as much tube surface as straight tube bundles, due to the bending radius, and the curved ends cannot be easily cleaned. Additionally, interior tubes are difficult to replace, many times requiring the removal of outer layers, or simply plugging the tube. Because of the ease in manufacturing and service, it is common to use a removable tube bundle design when specifying U-tubes.


Typical U-Tube Bundle

Tubesheets of Heat Exchangers

Tubesheets are usually made from a round flat piece of metal with holes drilled for the tube ends in a precise location and pattern relative to one another. Tube sheet materials range as tube materials. Tubes are attached to the tube sheet by pneumatic or hydraulic pressure or by roller expansion. Tube holes can be drilled and reamed and can be machined with one or more grooves. This greatly increases the strength of the tube joint.

The tubesheet is in contact with both fluids and so must have corrosion resistance allowances and have metalurgical and electrochemical properties appropriate for the fluids and velocities. Low carbon steel tube sheets can include a layer of a higher alloy metal bonded to the surface to provide more effective corrosion resistance without the expense of using the solid alloy.

The tube hole pattern or "pitch" varies the distance from one tube to the other and angle of the tubes relative to each other and to the direction of flow. This allows the manipulation of fluid velocities and pressure drop, and provides the maximum amount of turbulance and tube surface contact for effective Heat Transfer.


Typical Tube Sheet

Where the tube and tube sheet materials are joinable, weldable metals, the tube joint can be further strengthened by applying a seal weld or strength weld to the joint.A strength weld has a tube slightly reccessed inside the tube hole or slightly extended beyond the tube sheet. The weld adds metal to the resulting lip.A seal weld is specified to help prevent the shell and tube liquids from intermixing. In this treatment, the tube is flush with the tube sheet surface. The weld does not add metal, but rather fuses the two materials.In cases where it is critical to avoid fluid intermixing, a double tube sheet can be provided. In this design, the outer tube sheet is outside the shell circuit, virtually eliminating the chance of fluid intermixing. The inner tube sheet is vented to atmosphere so any fluid leak is easily detected.

 

U bend Seamless Stainless Steel Tube

Standard: ASTM A249 /ASME SA 249 ,ASTM A213 /ASME SA 213, ASTM A269/ASME SA269 , A312, A 688,A803, A789, A790, A376, EN 10216-5, EN 10297,DIN 17456, DIN 17458, GOST 9941, GOST 9940, JIS G3446 JIS G3447 JISG3448 JIS G3459 JIS G3463 JIS G 3468


Material:

TP304/304L, TP316/316L, TP321309S, 310S, 2205, 2507, 904L,TP405, TP409, TP410S, TP430, TP439

08X18H10 03X18H11 08X18H10T 12X18H10T 08X17H14M2 03X17H14M2 10X17H13M2T 20X23H18

SUS304TP SUS304LTP SUS304HTP SUS316TP SUS316LTP SUS316HTP, SUS321TP, SUS321HTP, SUS347TP, SUS347HTP, SUS310STP SUS317TP, SUS890LTP,


EN1.4301, 1.4306, 1.4948, 1.4401, 1.4404, 1.4571, 1.4541, 1.4833, 1.4878, 1.4550, 1.4462, 1.4438, 1.4845.

Size Range for tubing: OD:1/4" (6.25mm) to 8" (203mm), WT 0.02" (0.5mm) to 0.5"(12mm)

Length:

30 m(Max) or as your requirement

Process: EFW (TIG) ,laser welding

Finish: Annealed & pickled, bright annealing, polished

Ends: Beveled or plain end, square cut, burr free ,Plastic Cap at Both end

Packing: Bare packing/bundle packing with woven bag/wooden or steel frame crate packing/plastic cap protection at the both sides of tubes and suitably protected for sea-worthly delivery or as requested.

 

ASTM B111 C71500 Seamless copper U bend tubes,Jiangsu Haohua Industry Group as one of the leading suppliers in China to supply Seamless copper U bend tube etc.

Material  c10200,c10400,c10500,10700,c11000,c12000,c12200,c12300

Standard  ASTM B280, JIS H3300, CNS 5127,EN 1057, YS/T450-2002

Size  Out Diameter:3mm-400mm

Wall Thickness:0.1mm-50mm

Hot Sale to USA,UAE,Europe,Asia.

Property  Light Weight,Good Thermal Conductivity,Low Temperature and High Strength

Hardness and Corrosion Resistance,High Temperature and Pressure Resistance

It can be jointed,safe and can change the shape any time

Application       Seawater desalination device

Oil Cooler/Condenser

FuelBurning and Nuclear Power Plant use in condenser and Shipping used in

Condenser and Heated supply water distilling apparatus and heat exchange

Water pipe,Supply Heat and Condenser pipe

TS heat exchanger tubes can also be supplied as 'u' bends or serpentines, manufactured according to various heat exchanger standard or to customer's own specifications.


Standard Technical Range

OD 9.5mm  - 38.1mm

WT up to 6.35mm

Bending radii 1.25 x OD up to 1700mm

Bends can be supplied in accordance with TEMA R / ASTM SA/A556

Leg length up to 15000mm

Heat treatment where required by electric furnance or direct resistance

Hydrotesting up to 10,000 psi

Additional Testing


U-tubes with round bends

Box-shaped U-tubes (2 x 90° with straight intermediate lengths)

U-tubes from plain and finned tubes

Pipe dimensions: from 6,0 - 60,3 mm

Straight pipe lengths up to 40 metres

Materials: Stainless steel alloys, nickel-based alloys, titanium alloys, non-ferrous metals, carbon steels (further materials and alloys on request)

Leak tests using cold water pressure test up to 600 bar

Fully automatic heat treatment and pressure testing plants

U-tube glass bead blasting for stainless steel pipes

Purity tests inside and outside

Quality tests

CNC-controlled bending machines

CNC-controlled plane tables and saw benches

Dye penetrant of 'U' bend area

PMI testing

Heat Treatment

We are equipped to carry out heat treatment of bends plus a minimum 150mm of leg.


Heat Treatment Equipment

Heat treatment equipment is computer controlled with the added facility of data recording.

An argon protective atmopshere is used inside stainless and special alloy tubes during heat treatment.

We can provide all types of annealing; solution annealing and stress relieving.

Measuring, Cutting, Deburring and Cleaning

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

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


Packing

For roadfreight in timber fingers or skids.

In strong open or closed wooden boxes depending destination.

Each bundle is protected with plastic sheets.

Customers can provide their own packing or TS can prepare a packing plan.

Detailed packings lists are attached to wooden cases to give quick and clear identification of contents.

 

Latest type of "U" bending machine is used for precision cold bending of tubes. Specifically prepared jigs and fixtures are used to ensure three dimensional accuracy for “U” bend tubes. Bending is done for all kind heat exchanges, condenser, economizer , boiler tubes in carbon steel, alloy steel and stainless steel seamless as well as welded. HT of bent portion is carried out.

 

AT HMTL Tubes Can Be "U" Bent Up To R=1 Dia. ( Subject To Size) :

Subsequent to “U” bending tubes are hydro tested and stress relieved if asked for. Also mock-up pieces are prepared for determining thickness reduction on the bend portion is done to detect cracks, flaws or any type of defects. Special packing is provided to prevent any damage during transit.

 

Stress Relieving Of Carbon Steel And Alloy Steel ”U” Tubes

"U" bent portion + 300mm on each leg length are annealed (Stress Relieved) in a batch type furnace in which temperature is closely monitored, controlled and recorded. Rate of Cooling can be controlled as per heat treatment cycle given by customer..


Heat Treatment Of Stainless Steel “U” Tubes

“U” bent portion + 300mm on each leg length are heated at 1050 C temperature by transformer. The temperature is measured by an Optical Pyrometer. Cooling is done immediately by blowing cold air to avoid carbide precipitation.

'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.

All procedure is strictly followed as per TEMA "C" and ASTM A-688.

 

U tubes can be supplied to most outside diameters, thickness, material specifications and radii. Tubes are manipulated to the tolerance of TEMA R as a minimum.

Bend areas plus necessary straight leg sections can be heat treated in accordance with specified requirements.

U Tubes can also be hydrostatically tested if required. We can offer a range of additional testing on request, including dye penetrant and PMI testing.

U Tubes can be packed into solid wooden export cases (ISPM-15), or supplied in finger pallets to suit clients requirements. For both options all tubes are separated to facilitate easy assembly of bundles at site.


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