1. Strict Adherence to ANSI B16.5 Dimensional Baselines
As a mature ASTM A182 F51 Flange Manufacturer, we know that standards are the bedrock of engineering safety. ANSI B16.5 Class 150 specifies more than just OD and thickness; it mandates strict bolt hole spacing. Each flange is inspected with precision tools to ensure a "zero-distance" seamless fit with your piping system.
2. Machining Challenges of High-Hardness F51/F53 Materials
While duplex steel is superior, its high strength poses machining challenges. Standard lathes often struggle with the surface finish of ASTM A182 F51/F53. As a direct flange manufacturer, we use advanced CNC machines with custom tooling and a scientific Forging Process to enhance machinability, keeping face roughness strictly within Ra 3.2-6.3μm.
Table 1: Key Dimensions for Class 150 Threaded Flanges (ASME B16.5)
| Nominal Pipe Size (NPS) | Outside Diameter (mm) | Thickness (min. mm) | Bolt Hole Qty | Bolt Circle Dia (mm) |
| 1/2" | 88.9 | 11.2 | 4 | 60.5 |
| 1" | 108.0 | 14.2 | 4 | 79.2 |
| 2" | 152.4 | 19.1 | 4 |
120.7 |
3. NPT Threads: The Key to Sealing
The success of a threaded flange lies in thread precision. Our Class 150 Threaded Flanges feature NPT threads per ASME B1.20.1. With factory quality control, taper, depth, and angles are verified with precision gauges. Backed by MTR Certification, we guarantee not just the dimensions, but that threads won't strip or leak under pressure fluctuations.
4. Forging and Raw Material Quality Control
Precision starts with the blank. Unlike cheap castings, we as an F51 Flange Manufacturer insist on 100% forging. High-pressure forging eliminates internal pores and cracks, aligning the grain flow. This high-quality blank provides a perfect geometric foundation for finishing, avoiding dimensional deviations caused by material flaws.
Table 2: Dimensional Tolerances per ASME B16.5
| Feature | Tolerance Range (NPS ≤ 10") | Quality Check Method |
| Outside Diameter | ± 1.6 mm | Caliper / Gauge |
| Threading | ± 1 turn (Hand Tight) | L1 Thread Plug Gauge |
| Bolt Hole Center | ± 1.6 mm | CMM / Template |
5. Bolt Hole Alignment and Face Squareness
In long pipelines with multiple connections, slight bolt hole offsets cause failure. Our digital workflow ensures perfect symmetry. We also strictly control face squareness to prevent uneven stress during tightening—crucial for high-hardness F51/F53 to protect gaskets and ensure long-term sealing.
6. Factory Direct: Ensuring Uniform Specifications
The biggest advantage of choosing a direct F51 Flange Manufacturer is batch consistency. Whether you need 10 or 1000 ASTM A182 F51/F53 ANSI B16.5 Class 150 Threaded Flanges, our standardized lines ensure identical specs. With MTR Certification traceability, project acceptance becomes effortless.
Table 3: Comparison of Machining Standards
| Detail | Our Factory (CNC) | Generic Small Workshop |
| Machining Accuracy | ± 0.05 mm | ± 0.5 mm |
| Surface Finish (Ra) | 3.2 - 6.3 μm | 12.5+ μm |
| Thread Testing | Gauge + Profile Projector |
Manual Visual Check |
Obtaining precision-certified flanges is only the first step; improper installation can ruin expensive materials. Read our [Installation Guide] to master professional tips for preventing duplex steel thread galling.
