U Bend Tube A 556 / 556M Cold Drawn Carbon Feedwater Heater Black Seamless Steel Pipe

A 556 / 556M Cold Drawn Carbon Feedwater Heater Black Seamless Steel Pipe

1. Referenced Documents
1.1 ASTM Standards:
A 450/A 450M Specification for General Requirements for Carbon, Ferritic Alloy, and Austenitic Alloy Steel Tubes E 30 Test Methods for Chemical Analysis of Steel, Cast Iron, Open-Hearth Iron, and Wrought Iron

2. Manufacture

2.1 Manufacture—Tubes shall be made by the seamless process and shall be cold drawn.

2.2 Heat Treatment:
2.2.1 Cold-drawn tubes shall be heat treated after the final cold-draw pass at a temperature of 1200°[640°C] or higher to ensure ductility satisfactory for rolling into tube sheets and to meet mechanical properties as specified.
2.2.2 If stress-relief anneal of the U-bends is specified, the anneal shall consist of heating the bent portion within a range of 1100 to 1200°F [585 to 640°C].

3. Chemical Composition
3.1 The steel shall conform to one of the requirements as to chemical composition as prescribed in Table 1. 3.2 When a grade is ordered under this specification, supplying an alloy grade that specifically requires the addition of any element other than those listed for the ordered grade in

4. Permissible Variations in Dimensions (Fig. 1)
4.1 Permissible variations from the specified outside diametershall not exceed 0.004 in. [0.10 mm] for tubing under1.0-in. [25.4-mm] outside diameter nor 0.006 in. [0.15 mm]for tubing 1.0 in. [25.4 mm] to 1.25 in. [31.7 mm] inclusive.These tolerances do not apply to the bent portion of theU-tubes. At the bent portion of a U-tube for R = 2 D orgreater neither the major nor minor diameter of tube shalldeviate from nominal by more than 10 %. If 1 ⁄ D is specified,tolerances could be greater.
4.2 Permissible variations from the specified minimum wallthickness shall not exceed +20 % or −0. The wall thickness of

the tube in U-bent section shall be not less than valuedetermined by:
tf T 2R / 2R D (1)
where:
t = wall thickness after bending, in. [mm],
T = specified minimum tube wall thickness, in. [mm],
R = centerline bend radius, in. [mm], and
D = nominal outside tube diameter, in. [mm].

QUALITY CONTROL

1~ Incoming Raw Material Inspection
2~ Raw Material Segregation to avoid steel grade mix-up
3~ Heating and Hammering End for Cold Drawing
4~ Cold Drawing and Cold Rolling, on line inspection
5~ Heat Treatment, +A, +SRA, +LC, +N, Q+T
6~ Straightening-Cutting to specified length-Finished Measuring Inspection
7~ Machanical Testing in own labs with Tensile Strength, Yield Strength, Elongation, Hardness, Impact, Mictrostruture etc
8~ Packing and Stocking.

100% of our steel tubes are dimensionally checked
100% of our steel tubes are visually checked to assure they have a perfect surface condition and no surface defects.
100% eddy current test and ultrosonic test to eliminate longitudinal and transversal defects.