Description
Traceable alloy butt-weld fitting
ASTM B366 Monel 400 Eccentric Reducer
A procurement-ready eccentric butt-weld reducer in ASTM B366/B366M, UNS N04400 nickel-copper alloy, supplied for marine, seawater, alkali and selected hydrofluoric-acid service with project-defined dimensions, wall, construction and inspection.
What is a Monel 400 eccentric reducer?
An eccentric reducer changes between two pipe sizes while keeping one side of the fitting flat. The offset geometry is commonly selected in horizontal liquid, gas and pump-associated piping where pocket formation, drainage or venting must be controlled.
Monel 400 is the widely searched trade-name description for UNS N04400. It is considered for seawater, marine utilities, caustic alkali and selected hydrofluoric-acid duties, subject to exact fluid chemistry and operating conditions.
Technical specification
| Product type | Eccentric butt-weld reducer |
|---|---|
| Material | ASTM B366/B366M, UNS N04400 nickel-copper alloy |
| Material family | Nickel-copper alloy |
| Dimensional basis | ASME B16.9 factory-made wrought butt-welding fittings |
| Configuration | Eccentric transition with one flat side and offset pipe centerlines |
| Nominal size | Standard ASME large-end x small-end combinations; special combinations subject to technical review |
| Wall thickness | Standard schedules, heavy wall and project-specific wall subject to manufacturing review |
| Construction | Seamless or welded as applicable, ordered and permitted by the material class |
| End preparation | Butt-weld bevel matched to connecting pipe wall and approved welding detail |
| Heat treatment | Final condition and any heat treatment as required by ASTM B366 and the ordered class |
| Documentation | EN 10204 3.1 MTC, heat traceability, PMI, dimensions and additional NDE as ordered |
Available size and wall combinations depend on alloy, forming route, construction and quantity. Confirm the exact pipe outside diameter and wall in the RFQ.
Standards and technical references
Dimensional standard
ASME B16.9 covers standard factory-made wrought butt-weld eccentric-reducer dimensions, tolerances, marking and related requirements.
Material specification
ASTM B366/B366M covers factory-made wrought nickel and nickel-alloy pressure-piping fittings.
Why select Monel 400?
UNS N04400 is considered for seawater handling, marine equipment, salt production, caustic systems and selected hydrofluoric-acid process equipment.
| Selection point | Monel 400 | Inconel 625 |
|---|---|---|
| Alloy family | Ni-Cu | Ni-Cr-Mo-Nb |
| Typical focus | Marine, alkali and selected HF service | Chloride, seawater and severe mixed service |
| Oxidizing media | Requires careful condition review | Broader resistance in many oxidizing environments |
| Selection | Verify exact medium and aeration | Verify exact medium and temperature |
Typical applications
| Industry | Typical fitting duty | Why this material is considered |
|---|---|---|
| Marine engineering | Horizontal pump-suction size transition where the approved orientation controls vapor pockets | Seawater and salt-handling systems |
| Chemical processing | Horizontal liquid or gas piping requiring drainage or venting control | Selected alkali and hydrofluoric-acid systems |
| Industrial utilities | Equipment nozzle connection with offset large- and small-end centerlines | Brine and corrosive water services |
Application examples are selection context, not a design approval. Confirm process chemistry, pressure, temperature, weld procedure and governing code.
Manufacturing, inspection and documentation
Eccentric-reducer manufacture requires control of both end diameters, overall length, offset, flat-side alignment, wall transition, ovality and bevel geometry. N04400 orders commonly specify PMI, surface cleanliness, dimensional inspection and the applicable B366 construction class.
Heat-number traceability and PMI when specified.
Large/small-end OD and wall, overall length, eccentric offset, flat-side alignment, ovality and bevels checked.
PT, MT where applicable, UT, RT or third-party witnessing to the ordered scope.
MTC, heat-treatment and inspection records compiled to project requirements.
RFQ checklist
- Complete material grade and UNS where applicable
- ASME B16.9 edition or approved project drawing
- Run, outlet and branch sizes
- Schedule or exact wall thickness at every end
- Seamless or welded construction/class
- Bevel detail and matching pipe dimensions
- Quantity, destination and required delivery date
- EN 10204 3.1, PMI, dimensional and NDE requirements
Frequently asked questions
What is a Monel 400 eccentric reducer?
It is a Eccentric butt-weld reducer manufactured from ASTM B366/B366M, UNS N04400 nickel-copper alloy. Its large and small ends are offset so one side remains flat through the size transition. The ordered material specification controls chemistry, mechanical properties, heat treatment and testing.
Which standard applies to this fitting?
ASME B16.9 covers standard factory-made wrought butt-weld eccentric-reducer dimensions, tolerances, marking and related requirements. The material basis is ASTM B366/B366M, UNS N04400 nickel-copper alloy. The purchase order must state the required edition, construction, size, wall and supplementary examinations.
Where is Monel 400 typically selected?
UNS N04400 is considered for seawater handling, marine equipment, salt production, caustic systems and selected hydrofluoric-acid process equipment. Material suitability still depends on fluid chemistry, pressure, temperature, fabrication, corrosion allowance and the governing piping code.
Can heavy-wall and welded construction be supplied?
Yes, subject to manufacturing review. Provide the exact outside diameter, wall thickness or schedule, construction class, end preparation, quantity and NDE requirements so feasibility can be confirmed.
What should an RFQ include?
State the complete material grade, dimensional standard or approved drawing, run and branch sizes, schedule or exact wall, seamless or welded construction, bevel detail, quantity, destination, certification and inspection scope.
Product image is representative. Surface appearance varies by alloy, manufacturing route and finish.
Request a technical quotation
Send the material, size combination, wall, quantity, drawing or standard, and inspection requirements for review.
