High-Strength Alloy Lap Joint Flanges Class 300 with Stub Ends (ASME B16.5)

High-Strength Alloy Lap Joint Flanges Class 300 with Stub Ends (ASME B16.5)

The high-strength alloy lap joint flange assembly comprises two components: a stub end (manufactured from compatible or high-performance alloy) and a backing flange (which can be produced from more economical carbon steel). The backing flange can rotate freely around the stub end, allowing accurate bolt hole alignment and easier installation, particularly in confined spaces or systems that need regular disassembly. This structure delivers outstanding economic benefits when used with expensive corrosion-resistant alloys.

1. Product Description

The backing flange is a flat ring with a raised face and a low hub with a smooth bore designed to fit the stub end. It is not welded to the pipeline. The stub end, equipped with a lap section that matches the flange face, is connected to the pipe by butt welding. The two parts are assembled as a unit before being bolted to the connecting flange.

2. Key Parameters

The stub end complies with ASME B16.9, while the flange meets ASME B16.5 dimensional requirements. They are available in various pressure ratings from Class 150 up to Class 1500 and in a full range of nominal pipe sizes. The stub end is generally made from premium alloy material (such as ASTM A403 WP316), whereas the backing flange can be carbon steel (ASTM A105).

3. Applications

These flanges are especially suitable for high-cost alloy piping systems (including stainless steel, duplex steel and nickel alloys) or lined pipelines, since only the stub end needs to be made from special alloy materials. They are widely applied in systems requiring frequent disassembly for cleaning or inspection, including food processing, pharmaceutical and pulp & paper industries. They are also ideal for narrow installation spaces where rotating the entire pipe section is challenging.

4. Advantages

Significant cost reduction is achieved by using a carbon steel backing flange together with an alloy stub end. Bolt hole alignment problems during final installation are eliminated, as the flange can rotate freely. Friction and damage to flange sealing faces during bolt tightening are reduced. Maintenance and inspection operations are also greatly simplified.

5. Functionality

This design provides a reliable flanged connection in which the sealing surface is formed by the lapped stub end, while the backing flange supplies the mechanical strength required for bolting. This setup allows the piping system to be easily aligned and disassembled without affecting the welded joint between the stub end and the pipe.

Payment & Invoicing

1. First-Time Clients: 50% advance payment, 50% balance before shipment.
2. Strategic Clients: 30% advance, 70% payment against copy of Bill of Lading.
3. Long-Term Agreements: 60-day credit terms available (subject to credit approval).
4. Invoicing: 13% VAT Special Invoice provided; FORM A Certificate of Origin for exports.
5. fication System: Laser marking includes material code, pressure rating, and flow direction arrows.

FAQ

1. Are you trading company or manufacturer ?
We are manufacturer ,You can see the Alibaba 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.