Product Specifications: DN25 (D32), DN32 (D40), DN40 (D50), DN50 (D63), DN65 (D7...
Product Specifications: D40*32, D50*32, D50*40, D63*32, D63*40, D63*50, D75*40, ...
A 1-inch PVC screw plug costs less than a coffee, yet the wrong one can split the threaded boss on a filter housing and take a line down for a shift. On a dosing skid or a water-treatment header, that small threaded part is often the last thing specified and the first thing to leak. The specification sheet matters far...
View MoreA 110 mm PVC flange on a brine line starts weeping three weeks after commissioning. The bolts feel tight, the pipe is sound, and the gasket matched the size on the drawing. In most cases like this, the gasket itself is not faulty — the selection is. An EPDM pad went onto a stream carrying oil mist, a full-face gasket ...
View MoreWhen a plastic flange weeps at the bolt circle, the flange body is usually the last component to blame. On most PPH, PPN and PVDF lines the leak starts with the gasket, the bolt load or the alignment of the two faces, not with the moulded part. That order of causes matters, because it tells you what to specify before ...
View MoreWhat is Flange Softening?
1. Flange softening refers to the gradual decrease in hardness and strength of the flange material at the flange connection due to long-term pressure, temperature cycling, or media corrosion, causing the sealing surface to lose its original elasticity and tightening performance.
2. Softening can cause flange deformation and reduced bolt preload, leading to leakage or failure, especially in pipeline systems operating under high pressure, strong corrosion, or high temperature conditions.
3. In practical engineering, softening often manifests as loose flange bolts, deeper indentations on gaskets, or the appearance of micro-cracks; these are all signals requiring timely detection and maintenance.
How to reduce the risk of Flange Softening through material selection or process control?
1. Select softening-resistant materials
Using high-strength alloy steel or corrosion-resistant stainless steel flanges can significantly improve softening resistance.
For special media (such as acids, alkalis, and seawater), titanium alloy or nickel-based alloy flanges can be used to resist softening caused by chemical corrosion.
2. Optimize Heat Treatment Process
By using heat treatments such as normalizing, tempering, or quenching, the hardness and toughness of the material are improved, reducing the tendency to soften under high-temperature cycling.
Adding a residual stress relief process during flange production ensures that the flange achieves a uniform internal stress distribution before use.
3. Surface Protection and Anti-corrosion Coating
Spraying anti-corrosion paint, thermal spraying galvanizing, or ceramic coatings on the flange surface effectively prevents the media from corroding the metal substrate.
For pipeline systems requiring long-term operation, regular surface inspection and recoating are necessary to maintain the integrity of the protective layer.
4. Rational Design of Bolt Preload and Stiffness
Using high-strength bolts and calculating the preload according to standards ensures that the flange maintains sufficient clamping force under working pressure.
Adding reinforcing ribs or rigid supports to large-diameter or high-pressure flanges reduces the elastic deformation of the flange body.
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