U Tube & Tube Bending
Longda has a complete set of manufacturing and testing equipments, which are the most advanced in the technical tube industry .Meanwhile, we have established an effective
quality management system with strong execution.
We manufacture and control the products in accordance with ASTM (American Society
of Testing Materials) & ASME (American Society of Mechanical Engineers) standards.
1.Copper & Copper Alloys& Tube
ASTM B111, ASTM B395, ASME SB111, ASME SB395
Chinese Standard: GB/T1527, GB/T 8890
DIN EN12451, DIN EN12449, EN10204
2.Monel & Nickel Copper Tube and Nickel & Nickel Alloy Tube
ASTM B163/ ASME SB163, JIS H4552
Chinese Standard: GB/T 2882
DIN EN17751
3.Carbon Steel Tube: ASTM A179 ,ASME SA179
4.Stainless Steel Tube :ASTM A213,ASME SA213
5.Titanium & Titanium Alloy Tube :ASTM B338, ASTMB861,ASME SB338 ,ASME SB861, GB/T 3624, GB/T 3625
Tube Material
Tube Material
China GB
ISO
EN
UNS
JIS
Admiralty Brass
HSn70-1
CuZn28Sn1As
CW706R
C44300
C4430
Aluminum Brass
HAl77-2
CuZn20Al2As
CW702R
C68700
C6870
Copper Nickel 90/10
BFe10-1-1
CuNi10Fe1Mn
CW352H
C70600
C7060
Copper Nickel 90/30
BFe30-1-1
CuNi30Mn1Fe
CW354H
C71500
C7150
Carbon Steel Tube
10
-
E215
A179
STB340
Stainless Steel
06Cr19Ni10
-
X5CrNi18-10
304
SUS304
Stainless Steel
06Cr17Ni12Mo2
-
X5CrNiMo17-12-2
316
SUS316
Titanium Alloy
TA1
-
TI1
GR1
-
Titanium Alloy
TA2
-
TI2
GR2
-
Nickel
N7
-
2.4066
N02200
NW2200
Nickel
N5
-
2.4068
N02201
NW2201
Monel & Nickel Copper
NCu30
-
2.4360
N04400
NW4400
Inconel
NCr15-8
-
2.4816
N06600
NCF600TB
Range of Available Dimensions
For Copper &Copper Alloy Heat Exchanger and Condenser Tube ,dimension tolerance will be carried acc.to
ASTM B395.
1) Outside Diameter
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 , 38.1
The outside diameter of the straight leg portion of the tube ,exclusive of the central heavy gage portion ,shall not vary from that specified by more than the values shown it the table as below.
2) Wall Thickness
Wall thickness of Tube in U-bent Section-The wall thickness of the tube at apex of the U-bent section shall be not less than the value determined by following equation:
tf =t(2R)/(2R+D)
where:
tf = thickness after bending ,in.
t= specified thickness of minimum wall or specified nominal wall minus the permissible wall thickness tolerance ,in.
R=centerline bend radius ,in., and
D= norminal outside diameter of the tube, in.
3) Ovality for finished U -Tube
In the U- bend section, ovality shall not exceed 10% of the nominal tube outside diameter.
(ODmax - ODmin)/Nominal OD
4) Bending radius : Minimum: 15mm , Maximum: 1500 mm
Radius Tolerance
1) for R 100 mm +/- 3 mm
2) for R ≥ 100 mm +/- 5 mm
5) Initial Length
Maximum lengths of 20000mm can be supplied on request
6) Straightness tolerance: max.1.5 mm per 1 m
U-Tube ends: plain, vertically cut to the tube axis
7) Squareness of Cut-The departure from squareness of the end of any tube shall not exceed the values given in the Table as below.
Main Testing Terms and Procedure:
1. Heat Treatment
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 measuring of Wall Thickness
7. Mechanical Tests includes Tension Test, Flattening Test, Flaring Test, Hardness Test, etc
8. Grain Size Test
9. Trough Ball Test
10. 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.
Application & Advantage
Bends can be Heat Treated in accordance with Clients' requirements followed by hydrostatic testing if required. U-tube are widely used in heat-exchanger systems. U-tube heat exchangers Designed for high temperature applications, especially steam condensing or hot oil systems.
U-tubes are applied to heat exchangers, condensers, pre-heaters and other applications. These U-Tubes are made in accordance with requirements of ASTM B111/ASME SB111, ASTM B163 / ASME SB 163, ASTM B338/ASME SB338, ASTM A179/ASME SA179,ASTM A213/ASME SA213,DIN 28179,other statutory requirements or specifications.
1) Save Money
You avoid transport damages to the long initial tubes on the way to the bending company
You save the expensive sea freight costs for the long initial tubes ,and you don’t pay the extra costs for the carriage to the bending company
You save space and time for assembling the heat exchangers as the U-tubes can be removed radius-wise from the wooden combs
2) Surface Quality
You receive tubes which are free from oil and grease as well as free from debris
You receive a metallic bright surface without discolouration on the inner and outer tube
3) Heat treatment of bending area
You can choose between solution or stress relief annealing depending on the material standard