Overview

U-Bend Tube are widely used in Heat Exchanger Systems. Heat-Exchanger Equipment on the basis of Seamless Stainless U-Tubes and Welded Stainless U bend Tube is essential in strategically important andcritical felds--Nuclear And Petrochemical Machine Building. YUHONG GROUP Start to Produce U Bending Tube Since 2006, Up to now already supply more than 30000 tons Stainless Steel U Bend Tube to 55 countries

Grade 304L stainless steel, as known as ultra-low carbon stainless steel, is a versatile stainless steel material that is widely used to make equipment and parts that require good comprehensive performance (corrosion resistance and formability). It is a variant of 304 stainless steel with lower carbon content and is used where welding is required. The lower carbon content minimizes the precipitation of carbides in the heat-affected zone near the weld, and the precipitation of carbides may cause stainless steel to produce intergranular corrosion (welding erosion) in certain environments.

ASTM A213 Grade 304L tube has poor forging performance and is difficult to deform. Due to the phenomenon of work hardening, the amount of deformation in the process of mandrel drawing can not be too large. And the heat loss is relatively large. Therefore, it must be formed under many fires. It will cause coarse crystals if the high temperature holding stage is not handled well.

The U-Bend Tube Comply With The Following Standards:

1. ASTM A688/ASME SA688

2. ASTM A803/ASME SA803

3. ASTM A556/ASME SA556

Tube Of Other Alloys And Steel Grades Can Be Produced Upon Agreement.

Technical Requirements

Straight Tubes Standard Specification For Bending : ASME SA 213; ASME SB 163; ASME A789, ASME SA268, ASME SA269, etc.

Marking :Before Bending By Marking Machine All Over The Tube Length (Bent Section After Heat Treatment Without Marking).

Note :Marking is also possible After Bending On The Straight Parts Of U-Bending Tube.

U-Bend Tubes :

- TEMA RCB 2.31 Standard Of The Tubular Exchanger Manufacturers Association (9th Edition).

- ASTM A688/ASME SA688 Standard Specification For Welded Tubes Of Austenitic Corrosion Resistant Steel Grade Designed For Feed Water Boilers.

- ASTM B163/ASME SA163 Standard Techinical Requirements For Tubes Of Nickel And Nickel Alloy For Condensers And Heat Exchangers.

- Customer Specifications.

Bending Radius : From 1.5*OD(Outside Diameter) To 1500mm When Ordering Tubes With Radius less or equal to 1.5*OD, It Is Necessary To Agree Precision Of Geometrics.

Straight Tubes Maximum Length : (Before Bending) 35000 mm.

Leg Length : Min 1 Meter, Max. 16500 mm (For Max R=1500mm).

Note : Other Size Are Available Upon Agreement.

Heat Treatment : Stress Relieved After U-Bending (Bending Area Plus 300MM For Each Leg).

Hydrostatic Test After U Bending : Maximum Test Pressure 600 Bar, Soaking 10 Sec. With Dematerialized Water. Compressed Air Cleaning After Hydro-Test.

Packaging : In Strong Transport-Worthy Pre-fumigated wooden boxes of corresponding dimensions for each tube Length, Radius, Diameter, According To PO requirements as well as wrapped In polyethylene films With soft plastic caps on both end of Tube.

Features :

• 1. 'U' bending is done by cold working process.
• 2. 'U' bending is done to the required radius as per customer drawings.
• 3. The bend portion and six inch leg is stress relieved by resistance heating.
• 4. Inert gas (Argon) is passed through it at the required flow rate to avoid oxidation in ID.
• 5. The radius is checked for its OD and wall thinning with the recommended specification.
• 6. The physical properties and micro-structure is checked at three different position.
• 7. Visual inspection for waviness and cracks is done with Dye Penetrant Test.
• 8. Each tube is then hydro tested at the recommended pressure to check for leakage.
• 9. Cotton ball test is done to check the ID cleanliness of the tube.
• 10. Thereafter pickled, dried, marked and packed.
• 11. All procedure is strictly followed as per TEMA"C"and ASTM A-688.

Some of the quality tests carried out by us includes

Supplementary Testing

Apart from the above mentioned tests, we also carry out on the manufactured products supplementary testing. The tests conducted under this include: