News

Industry Overview & Market Trends

The global lapped flange market is projected to grow at 5.2% CAGR through 2030 according to GIA research. This growth is primarily driven by oil & gas infrastructure expansion and chemical processing plant upgrades. Lap joint flanges offer distinct advantages in systems requiring frequent maintenance where rotating the pipe isn't feasible during assembly.

Industry-wide adoption of ASME B16.5 standards ensures compatibility and safety across applications. Unlike weld neck flanges, lapped flanges use a two-component system: a stub end welded to the pipe and a backing flange that rotates freely. This design significantly reduces installation time and allows straightforward pipe alignment without rotating heavy assemblies.

Technical Specifications & Performance Data

Standard lapped flanges adhere to these critical specifications:

Parameter	Range	Standards	Performance Notes
Pressure Class	150# to 2500#	ASME B16.5	Highest ratings used in power generation systems
Materials	SS304, SS316, Duplex, Carbon Steel	ASTM A182/A105	Corrosion resistance critical in chemical applications
Temperature Range	-196°C to +650°C	ASME B16.34	Varies by gasket material selection
Pipe Sizes	1/2" to 24" (DN15 to DN600)	ISO 6708	Large diameters for refinery transfer lines
Face Types	Flat Face (FF), Raised Face (RF)	ASME B16.47	RF most common for industrial applications

Performance Charts

Engineering Applications

In refinery transfer systems, ASME B16.5 lap joint flanges with PTFE gaskets enable rapid pump replacement without pipe cutting. Offshore platforms standardized on DIN 2636 flange lap joint stub ends reduce maintenance downtime by 40% compared to weld neck alternatives.

Chemical processing plants frequently utilize ASTM A182 F304L lapped flanges with spiral wound gaskets in acid transfer lines. The non-integrated design prevents flange face corrosion from process media, significantly extending service life.

Expert FAQ: Technical Aspects

Installation Best Practices

Proper installation of lap joint flanges follows API 6AF requirements: First, weld the lap joint stub end to the pipe per WPS specifications. After cooling, slide the backing flange onto the pipe with flange facing away from the weld. Before final assembly, confirm the gasket surface shows no imperfections exceeding ASME B16.20 Ra 3.2 µm requirements. Torque bolts in star pattern sequence to 30% > 60% > 100% of specified torque values.

Quality Assurance & Testing

HEBEI JIUYUAN PIPELINE employs dual quality verification per API Q1 and ISO 9001:2015 standards. All lapped flanges undergo PMI (Positive Material Identification) testing using portable XRF analyzers, hydrostatic testing to 1.5 times design pressure per ASME B16.34 standards, and dimensional verification with coordinate measuring machines (CMM). Batch traceability provides documentation on melt chemistry and processing parameters for each component.

Industry References

1. ASME B16.5-2020: Pipe Flanges and Flanged Fittings
2. European Journal of Engineering Research: "Advanced Sealing Methods in Flange Connections" (DOI:10.24018/ejeng.2022.3.3.2851)
3. API 6A Specification for Wellhead and Christmas Tree Equipment
4. Journal of Pressure Vessel Technology: "Performance Analysis of Flanged Joints under Thermal Cycling Conditions" (DOI:10.1115/1.4038576)