ASME SB163 N04400 Nickel Alloy U-Bend Tube for Condenser and Shell & Tube Heat Exchanger
Product Overview
ASME SB163 N04400 Nickel Alloy U-Bend Tube | Seamless Monel 400 Heat Exchanger & Condenser Tube
Yuhong Group Co., Ltd. supplies comprehensive heat exchanger components including pressure vessels, air coolers, tube bundles, U-bend tubes, fin tubes, tube sheets, baffles, and heads. Our U-bend heat exchanger tubing expertise focuses on ASME SB-163 bend geometry, wall-thinning calculation, and end preparation.
This product is a seamless nickel-copper UNS N04400 U-bend tube designed for condenser and heat-exchanger service. ASME SB-163 covers OD 3 in. (76.2 mm) and under, minimum wall 0.148 in. (3.76 mm) and under, or average wall 0.165 in. (4.19 mm) and under. N04400 is furnished annealed or stress-relieved, with annealed ends available upon specification. Small-diameter light-wall converter sizes are covered by ASME SB-163 Appendix X2 when specified.
Chemical Composition
ASME SB-163 Table 1
| Element |
N04400, % |
| Nickel |
63.0 min |
| Copper |
28.0-34.0 |
| Iron |
2.5 max |
| Manganese |
2.0 max |
| Carbon |
0.3 max |
| Silicon |
0.5 max |
| Sulfur |
0.024 max |
Mechanical Properties and Conditions
ASME SB-163 Table 3
| Condition |
Tensile, min |
Yield 0.2% offset, min |
Elongation, min |
Hardness |
| Annealed |
70 ksi (483 MPa) |
28 ksi (193 MPa) |
35% |
-- |
| Stress-relieved |
85 ksi (586 MPa) |
55 ksi (379 MPa) |
15% |
B75 max for annealed ends |
N04400 is supplied annealed or stress-relieved. If stress-relieved tubing has annealed ends, the hardness after annealing must not exceed the ASME SB-163 Table 3 value. ASME SB-163 grain size requirements apply to UNS N08120, UNS N08810, and UNS N08811, not to N04400.
Manufacturing, Testing, and U-Bend Controls
Seamless N04400 tube is cold worked and heat treated. ASME SB-163 requires:
- Chemical analysis
- Tension testing
- Hardness testing when annealed ends are specified
- Flare testing
- Hydrostatic or nondestructive electric testing
The flare test is conducted on one end of 1% of finished tube lengths per lot (minimum one tube for lots under 100 tubes). A 60° expanding tool increases the specified outside diameter by 30%, and the flared specimen must show no cracking through the wall.
Each tube receives either hydrostatic or nondestructive electric testing. For hydrostatic testing, tubes with OD 1/2 in. (3.2 mm) and larger and wall 0.015 in. (0.38 mm) and over are tested to 1000 psi (6.9 MPa), provided the calculated fiber stress does not exceed the allowable S. For N04400, S is 17,500 psi (120.6 MPa) annealed and 21,200 psi (146.2 MPa) stress-relieved.
ASME SB-163 Supplementary S1 U-Bend Requirements
| Control |
ASME SB-163 S1 Requirement |
| Bend OD |
Within 10% of nominal at any cross section inside points of tangency |
| Apex wall |
Not less than TF = T(2R)/(2R + D) |
| Leg spacing |
Tolerance by centerline radius R: up to 18 in., 1/16 in.; over 18-30 in., 3/32 in.; over 30-36 in., 1/8 in. |
| Leg length difference |
Max 1/2 in. (3.2 mm) |
| Hydro after bend |
5 s minimum hold; 26,600 psi (183.3 MPa) fiber stress for pressure calculation |
Ordering, Customization, and Applications
Ordering information under ASME SB-163 includes alloy, condition, finish, dimensions, fabrication operations, testing requirements, ends, supplementary requirements, and inspection specifications.
Custom U-bend options include:
- Bend radius R
- Leg length
- Annealed ends
- Hydro after bending
- NDE and third-party witness
Matching tube sheets, baffles, heads, and fin tubes are available. Typical applications include condensers, heat exchangers, air coolers, tube bundles, and marine or chemical cooling duties where nickel-copper corrosion resistance is required. Seamless construction avoids longitudinal weld seams, while the U-bend design reduces field welds and accommodates thermal expansion.
Frequently Asked Questions
Average wall vs minimum wall? ASME SB-163 covers both. For U-bend apex wall calculation, T is the specified minimum wall or the specified average wall minus the permissible minus wall tolerance.
Is grain size required for N04400? No. The ASME SB-163 grain size requirement applies to UNS N08120, UNS N08810, and UNS N08811.
Can hydrostatic testing be done after bending? Yes, when specified. Minimum holding time is 5 s, and the required fiber stress for computing hydrostatic test pressure is 26,600 psi (183.3 MPa).
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