How 304 20592PL Flange DN25*PN6 Is Made

The Precision Behind Every Plate Welding Flange

Every Plate Welding Flange used in a pipeline tells a story of craftsmanship and engineering precision.
Among these, the 304 20592PL Flange DN25*PN6 has become a standard component for low-pressure connections in industrial, water, and chemical piping.

As a China-based flange manufacturer and large-scale supplier, we utilize advanced fabrication lines and strict quality control to deliver reliable, corrosion-resistant flanges that meet global expectations.
This article walks through the detailed production journey of a 304 20592PL flange — from raw material to final shipment.

1. Raw Material Selection and Initial Processing

Everything starts with the material.
For this flange type, 304 stainless steel is selected for its balanced properties — excellent corrosion resistance, strength, and weldability.
It contains around 18% chromium and 8% nickel, which forms a stable protective oxide layer on the surface.

Each batch of stainless steel is tested for:

·Chemical composition verification (via spectrometer)

·Surface inspection for cracks or inclusions

·Thickness and dimensional conformity

After inspection, stainless plates are cut into round blanks according to the HG/T 20592 standard dimensions, ensuring each blank aligns with the required DN25 PN6 specifications.

2. High-Precision Cutting and Forming

The circular blanks are cut with CNC-controlled plasma, laser, or water-jet systems, depending on the thickness and precision demands.
This automated process achieves:

·Smooth edges

·Consistent outer and inner diameters

·Precise bolt-hole positions

For DN25 PN6 flanges, this ensures the correct bolt circle and sealing face size, critical for tight connections in pressure pipelines.

After forming, the blanks undergo surface cleaning and leveling to remove residual oxides and ensure perfect flatness — preparing the part for later machining.

3. Machining and Optional Forging

While many plate welding flanges are produced directly from sheet material, certain clients require forged flange blanks for enhanced mechanical performance.
Forging improves the metal grain alignment, providing better strength and ductility under repeated stress.

Subsequent CNC machining operations refine all dimensions to within the HG/T 20592 and ISO 7005 tolerances:

·Center bore and bolt-hole accuracy

·Flat sealing surface (Ra ≤ 3.2 μm)

·Thickness uniformity across the flange body

Each flange is precisely machined on vertical lathes and CNC mills, ensuring compatibility with pipeline fittings during assembly.

4. Drilling, Polishing, and Surface Treatment

Next comes bolt-hole drilling, an essential step that defines flange alignment and sealing performance.
Automated drilling machines ensure accurate positioning based on the PN6 pressure class.

After drilling, the flange undergoes:

·Deburring and edge smoothing

·Pickling or polishing to enhance corrosion resistance

·Surface coating or anti-rust treatment (for temporary storage or export shipping)

These finishing touches help maintain a clean, uniform surface, ready for immediate welding or installation.

5. Identification, Testing, and Quality Verification

Every 304 20592PL Plate Welding Flange is permanently engraved with:

·Grade (304)

·Nominal size and pressure (DN25 PN6)

·Standard mark (HG/T 20592)

·Production batch and heat number

Quality checks include:

·Dimensional and tolerance verification

·Visual inspection for any cracks or surface flaws

·Mechanical strength testing (tensile/yield)

·Sealing tests when required by end-users

These steps ensure that each flange meets national GB/T and international ISO specifications before leaving the factory.

6. Packaging, Logistics, and Bulk Distribution

After passing inspection, each flange is carefully cleaned, lightly oiled, and packed in fumigation-free wooden crates or metal pallets.
Detailed labeling allows full product traceability during export.

Thanks to our large-scale China manufacturing base and bulk production capacity, we can meet both standard and customized orders.
Our factory supports OEM production, bulk supply, and fast delivery, ensuring clients receive consistent quality across large quantities.

7. Industrial Applications and Reliability

The 304 20592PL Flange DN25*PN6 serves a wide range of applications:

·Chemical processing lines for non-corrosive fluids

·Water treatment systems and low-pressure piping

·Food and pharmaceutical plants

·Marine and offshore equipment

Its corrosion resistance and weldable structure make it ideal for connecting pipes, valves, and fittings under moderate temperature and pressure conditions.

Conclusion: Trusted Plate Welding Flange Supplier from China

From stainless steel plate to precision-machined component, each 304 20592PL Flange DN25*PN6 reflects the discipline and innovation behind China’s plate welding flange manufacturing sector.

As a professional China flange manufacturer and bulk supplier, we emphasize durability, cost-efficiency, and dimensional precision in every batch we produce.
Our focus on process control and technical expertise ensures that every flange delivers long-lasting performance and seamless compatibility with global pipeline standards.

Whether for industrial projects or infrastructure upgrades, our 304 plate welding flanges continue to provide dependable solutions backed by large-scale production and strict quality control.

References

GB/T 7714:Suraj M, Tripathy S, Biswal S R, et al. Optimization of welding process parameters for joining of 304L stainless steel[J]. Materials Today: Proceedings, 2024.

MLA:Suraj, Md, et al. "Optimization of welding process parameters for joining of 304L stainless steel." Materials Today: Proceedings (2024).

APA:Suraj, M., Tripathy, S., Biswal, S. R., & Sahoo, T. K. (2024). Optimization of welding process parameters for joining of 304L stainless steel. Materials Today: Proceedings.