Lap Joint Flange (LJ Flange)

1️⃣ Product Introduction

VikTech Fittings is a leading manufacturer, exporter, and supplier of premium-quality Lap Joint Flanges (LJ Flanges) manufactured in accordance with ASME standards including ASME B16.5 and ASME B16.47, along with EN and DIN specifications.

Lap Joint Flanges are used together with a Stub End and are ideal for systems that require frequent dismantling for inspection and maintenance. The flange itself is not welded directly to the pipe; instead, it slides over the pipe and rests against the backing face of the stub end, allowing free rotation for easy bolt hole alignment.

This design makes Lap Joint Flanges highly suitable for low-pressure applications, corrosive environments, and systems where alignment flexibility is essential.

2️⃣ Technical Specifications

Product Name                      Lap Joint Flange (LJ Flange)

Standards                            ASME B16.5, ASME B16.47 Series A & B, EN 1092-1, DIN

Size                                     Range½″ (DN15) to 60″ (DN1500)

Pressure Class                   Class 150, 300, 400, 600

Facing Type                        Flat Face (Used with Stub End)

Manufacturing                    Forged / Plate (Depending on Size)

Bore Type                          Loose Type (Matches Stub End OD)

Certification                        EN 10204 3.1 / 3.2, IBR (On Request)

3️⃣ Available Material Grades

▶ Carbon Steel (CS)

• ASTM A105

• ASTM A350 LF2

• ASTM A694 F42 / F52

▶ Stainless Steel (SS)

• ASTM A182 F304 / 304L

• F316 / 316L

• F321

• F347

▶ Alloy Steel

• ASTM A182 F11

• F22

▶ Duplex & Super Duplex

• F51 (UNS S31803)

• F60 (UNS S32205)

▶ Nickel Alloys (On Request)

• Inconel 625

• Monel 400

• Hastelloy C276

4️⃣ Size & Pressure Range

• Size: ½″ to 60″

• Pressure Ratings: Class 150 – 600

• PN Rating: PN6 – PN100

• Custom drilling available

Lap Joint Flanges are typically used in lower pressure service compared to Weld Neck or Blind Flanges.

5️⃣ Standards & Compliance

• ASME B16.5 (Up to 24″)

• ASME B16.47 (Above 24″)

• EN 1092-1

• DIN Standards

• ISO Certified Manufacturing

• PED (On Request for Europe Projects)

6️⃣ Design & Features

• Used with Stub End

• Loose backing flange

• Free rotation for easy alignment

• Cost-effective solution in stainless steel systems

• Ideal for frequent dismantling

• Reduced flange cost when combined with CS backing flange & SS stub end

Dimensional accuracy maintained as per ASME tolerances.

7️⃣ Manufacturing Process

• Closed die forging (forged type)

• Plate cutting (large sizes)

• CNC machining

• Drilling & facing

• Surface finishing

• Final inspection & marking

8️⃣ Pressure & Temperature Ratings

MaterialTemperature RangePressure ClassCarbon SteelUp to 425°CClass 150 – 600Stainless SteelUp to 870°CPN6 – PN100DuplexUp to 300°CModerate Pressure

(Actual ratings depend on stub end and gasket selection.)

9️⃣ Testing & Quality Control

✔ Visual & Dimensional Inspection
✔ PMI Testing
✔ Hardness & Tensile Testing
✔ Ultrasonic Testing (If Required)
✔ Third Party Inspection – TUV / BV / SGS
✔ EN 10204 3.1 Certification
✔ Heat Number Traceability

🔟 Applications & Industries

• Oil & Gas Pipelines

• Petrochemical Plants

• Chemical Processing

• Water Treatment Plants

• Food & Beverage Lines

• Low Pressure Steam Lines

• Corrosive Media Systems

Lap Joint Flanges are especially beneficial in stainless steel piping systems where cost optimization is required.

1️⃣1️⃣ Surface Finish Options

• Anti-Rust Oil

• Black Coated

• Hot Dip Galvanized

• FBE Coated

• Zinc Coated

1️⃣2️⃣ Packing & Marking

• Wooden pallets / crates

• Bubble wrapping

• Plastic face protection

• Marking: Size, Grade, Class, Heat No., Standard

• Custom project marking

• Seaworthy export packing

1️⃣3️⃣ Why Choose VikTech Fittings?

• Accurate machining for perfect stub end fit

• Cost-effective stainless solutions

• Large diameter supply capability

• Fast delivery for project requirements

• Competitive pricing

• Export-ready documentation

• Reliable supply chain

1️⃣4️⃣ SEO Keywords

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