Stainless Steel 304/316L Butt Welding Concentric Reducer ASME B16.9 Class 150 for Piping Systems
Stainless Steel 304/316L Butt Welding Concentric Reducer ASME B16.9 Class 150
1. Product Description
Stainless steel reducers are strictly classified into two types based on centerline alignment. Incorrect selection directly impacts system safety:
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Concentric Reducer (CR): Both ends share the same centerline with symmetrical diameter reduction. Suitable for vertical risers, pump discharge vertical sections, or gas transmission lines, where fluid transitions evenly along the center. Not recommended for horizontal liquid lines due to potential bottom pooling.
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Eccentric Reducer (ER): Centerlines are parallel but offset, with one straight side (flat-bottom or flat-top installation). For horizontal liquid pipelines, flat-bottom installation (straight side down) is mandatory to prevent liquid accumulation and crevice corrosion. For horizontal gas pipelines, flat-top installation (straight side up) is required to prevent condensate pooling. This is the most critical engineering principle in reducer selection.
2. Product Applications
| Industry | Typical Media | Recommended Material |
| Petrochemical | Crude oil, refined products, sour gas | 316L / Duplex 2205 |
| Marine/Ocean | Seawater, salt spray | 904L / Super Duplex 2507 |
| Food & Pharmaceutical | Purified water, steam, CIP solutions | 304L / 316L (mirror-polished) |
| Power Generation | High-temp steam, feedwater | 321H / 347H (stabilized grades) |
| Semiconductor | High-purity gases, UPW | 316L EP-grade (electropolished) |
3.Product Advantages
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Solution Annealing: All forged/stamped products undergo solution annealing (1040～1120℃) followed by rapid water quenching, ensuring intergranular corrosion resistance and eliminating cold-work stresses.
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Full-Loop Inspection Chain: Raw material verification → dimensional check → forming temperature monitoring → ultrasonic wall-thickness verification → bevel angle inspection → surface roughness sampling → hydrostatic/pneumatic testing.
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NDT Coverage: 100% dye penetrant (PT) or magnetic particle (MT) inspection on weld ends; radiographic testing (RT) available upon request for pressure-retaining walls.
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Full Traceability: Each fitting is stamped with heat number, size, and standard. Material test certificates are provided with each shipment, ensuring full lifecycle traceability.
4.Key Product Parameters
| Ordering Item | Technical Details |
| Product Name & Type | Must specify "Concentric" or "Eccentric"; for Eccentric, indicate "Flat-Bottom" or "Flat-Top" |
| Material Grade + Heat No. | Example: 316L / Heat No. 2203-XXX (with MTC attached) |
| Size (Large End × Small End) | Example: DN200×DN100 (or 8″×4″) |
| Wall Thickness Schedule | SCH40S / SCH80S, etc. (large and small ends can be specified separately) |
| Applicable Standard | ASME B16.9 / GB/T 12459, etc. (must state edition/year) |
| End Connection Type | Butt Weld (BW) / Socket Weld (SW) / Threaded (specify thread standard) |
| Surface Finish Requirement | Pickled & passivated / Mechanically polished (Ra≤0.8μm) / Mirror polished (Ra≤0.4μm) / Electropolished |
| NDT Requirements | PT / MT / RT / UT (specify sampling rate or 100%) |
| Packaging Method | Wooden crates / Pallets / Steel banding, with plastic end caps on both ends |
| Marking Requirements | Stamped (Material + Size + Standard + Heat No.) or laser-engraved; stainless steel tags attached |
| Accompanying Documents | Material Test Certificate (EN 10204 3.1 or 3.2), Dimensional Inspection Report, Heat Treatment Report |
FAQ
1. Are you trading company or manufacturer ? We are manufacturer ,You can see the certification.
2.How long is your delivery time? Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.
3. Do you provide samples ? is it free or extra ? Yes, we could offer the sample for free charge but need pay the cost of freight.
4. What is your terms of payment ? Payment<=1000USD, 100% in advance. Payment>=1000USD, 50% T/T in advance ,balance before shippment.
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