Stainless Steel Lap Joint Flange Weight Chart with Dimensions & Pressure Ratings

Stainless Steel Lap Joint Flanges are widely used in industrial piping systems where frequent dismantling, easy alignment, and corrosion resistance are essential. Unlike other flange types, lap joint flanges work in combination with a stub end, allowing the flange to rotate freely around the pipe. This makes them highly suitable for applications requiring regular inspection, cleaning, or replacement.

Understanding the weight chart, dimensions, and pressure ratings of stainless steel lap joint flanges is critical for accurate material planning, load calculation, and system design. This guide provides a clear overview, along with standard reference tables used in engineering and procurement.

What Is a Stainless Steel Lap Joint Flange?

A Stainless Steel Lap Joint Flange consists of two components:

• A stub end welded to the pipe
  
• A loose backing flange that supports bolting and sealing
  

The flange itself does not come into contact with the process fluid, which allows the use of higher-grade stainless steel stub ends while keeping overall system cost under control. These flanges are commonly manufactured in ASTM A182 grades such as F304, F304L, F316, and F316L.

Extended Weight Chart

Nominal Size (NB)	Outside Diameter (mm)	Thickness (mm)	Bolt Holes	Approx. Weight (Kg)
½” (15 NB)	90	9.6	4	0.8
¾” (20 NB)	100	11.2	4	1.0
1” (25 NB)	108	11.2	4	1.2
1½” (40 NB)	127	12.7	4	1.9
2” (50 NB)	152	14.3	4	2.8
2½” (65 NB)	178	15.9	4	3.9
3” (80 NB)	190	15.9	4	4.9
4” (100 NB)	229	17.5	8	7.2
5” (125 NB)	254	19.1	8	9.8
6” (150 NB)	279	20.7	8	12.5
8” (200 NB)	343	22.3	8	19.8
10” (250 NB)	406	25.4	12	32.6
12” (300 NB)	483	28.6	12	48.4

Dimensional Parameters Considered in Weight Calculation

Lap Joint Flange weight is derived from:

• Outside Diameter (OD)
• Bore Diameter
• Flange Thickness
• Raised Face Height (if applicable)
• Number and Size of Bolt Holes
• Material Density (~7.9 g/cm³ for stainless steel)

Higher pressure ratings demand increased thickness and bolt size, which directly impacts flange mass.

Why Accurate Weight Matters

1. Structural support design
2. Pipe rack loading calculation
3. Crane and lifting capacity planning
4. Transportation and freight estimation
5. Cost control and procurement accuracy

Incorrect weight estimation can affect pipe stress calculations and installation safety.

Industry Applications

Stainless Steel Lap Joint Flanges with verified weight and pressure ratings are widely used in:

• Refinery piping systems
• Offshore platforms
• Chemical processing plants
• LNG terminals
• Power generation units
• Marine installations

Their rotating design simplifies alignment during erection, while precise dimensional and weight data ensure safe engineering practices.

Stainless Steel Lap Joint Flange – Standard Weight Chart

Flange Size (NB)	Pressure Class	Approx. Weight per Flange (kg)	Total Weight (kg) – 100 Nos
½” (15 NB)	Class 150	2.1	210
¾” (20 NB)	Class 150	2.8	280
1″ (25 NB)	Class 150	3.9	390
1½” (40 NB)	Class 150	6.5	650
2″ (50 NB)	Class 150	8.5	850
3″ (80 NB)	Class 150	15.0	1500
4″ (100 NB)	Class 150	23.5	2350
6″ (150 NB)	Class 150	42.0	4200
8″ (200 NB)	Class 150	66.0	6600
10″ (250 NB)	Class 150	95.0	9500

Extended Stainless Steel Lap Joint Flange Weight Chart

With Dimensions & Pressure Class Reference (ASME B16.5)

Accurate flange weight data is essential for piping layout design, stress analysis, structural load calculation, logistics planning, and cost estimation. Stainless Steel Lap Joint Flanges are generally lighter than weld neck flanges but still require precise weight consideration due to their use with stub ends in rotating and maintenance-intensive systems.

Below is an extended reference weight chart covering additional sizes and higher pressure ratings.

Stainless Steel Lap Joint Flanges are widely used in piping systems where frequent dismantling and alignment flexibility are required. Since these flanges are used with stub ends and are not directly welded to the pipe, accurate weight calculation becomes important for structural design, transportation planning, and installation safety. A detailed weight chart helps engineers and procurement teams determine the correct flange selection based on size, pressure class, and dimensional standards.

Importance of Weight Charts in Flange Selection

The weight of a stainless steel lap joint flange varies depending on:

• Nominal Pipe Size (NPS / NB)
  
• Pressure Class (150, 300, 600, etc.)
  
• Outside Diameter and Thickness
  
• Material Density (SS 304, SS 316, etc.)
  
• Bolt Circle Diameter and Number of Holes
  

Weight charts simplify project planning by providing approximate mass per piece, allowing accurate load calculations for pipe supports, racks, and lifting equipment.

Key Features

• Designed for use with stub ends for flexible installation
  
• Allows easy bolt alignment and rotation
  
• Suitable for frequent dismantling applications
  
• Excellent resistance to corrosion and chemical exposure
  
• Cost-effective solution for large diameter piping systems

Dimensions & Pressure Ratings

Stainless Steel Lap Joint Flanges manufacturer as per ASME B16.5 (up to 24”) and ASME B16.47 (for larger diameters). The pressure rating defines the maximum allowable working pressure at a given temperature.

Standard Pressure Classes

• Class 150
  
• Class 300
  
• Class 600
  
• Class 900
  
• Class 1500
  
• Class 2500
  

As the pressure class increases, the thickness, bolt size, and overall flange weight also increase accordingly.

Mechanical Properties of Stainless Steel Lap Joint Flanges

Grade (ASTM A182)	Tensile Strength (MPa) Min	Yield Strength (MPa) Min	Elongation (%) Min	Hardness (HB) Max
F304	515	205	30	201
F304L	485	170	30	192
F316	515	205	30	217
F316L	485	170	30	192
F321	515	205	30	217
F347	515	205	30	217
F51 (Duplex)	620	450	25	293
F53 (Super Duplex)	795	550	15	310

Stainless Steel Lap Joint Flange – Chemical Properties (ASTM A182 Forged Grades – by Weight)

Element (%)	F304	F304L	F316	F316L	F321	F347
Carbon (C)	0.08 Max	0.03 Max	0.08 Max	0.03 Max	0.08 Max	0.08 Max
Manganese (Mn)	2.00 Max	2.00 Max	2.00 Max	2.00 Max	2.00 Max	2.00 Max
Silicon (Si)	1.00 Max	1.00 Max	1.00 Max	1.00 Max	1.00 Max	1.00 Max
Phosphorus (P)	0.045 Max	0.045 Max	0.045 Max	0.045 Max	0.045 Max	0.045 Max
Sulfur (S)	0.030 Max	0.030 Max	0.030 Max	0.030 Max	0.030 Max	0.030 Max
Chromium (Cr)	18.0 – 20.0	18.0 – 20.0	16.0 – 18.0	16.0 – 18.0	17.0 – 19.0	17.0 – 19.0
Nickel (Ni)	8.0 – 11.0	8.0 – 12.0	10.0 – 14.0	10.0 – 14.0	9.0 – 12.0	9.0 – 13.0
Molybdenum (Mo)	—	—	2.0 – 3.0	2.0 – 3.0	—	—
Titanium (Ti)	—	—	—	—	5×C Min – 0.70 Max	—
Niobium (Nb + Ta)	—	—	—	—	—	10×C Min – 1.0 Max
Iron (Fe)	Balance	Balance	Balance	Balance	Balance	Balance

Stainless Steel Lap Joint Flange – Specification 

Parameter	Details
Product Type	Lap Joint Flange
Standards	ASME B16.5 / ASME B16.47
Material Grades	ASTM A182 F304, F304L, F316, F316L
Size Range	½” to 24″ (larger sizes on request)
Pressure Ratings	Class 150 to Class 2500
Facing Type	Flat Face (FF)
Surface Finish	CNC Machined / Smooth Finish
Manufacturing Process	Forged / Machined
Application Areas	Chemical, Oil & Gas, Power, Water Treatment

Applications of Stainless Steel Lap Joint Flanges

Due to their flexibility and corrosion resistance, these flanges are extensively used in:

• Chemical processing plants
  
• Oil & gas pipelines
  
• Pharmaceutical and food industries
  
• Water treatment systems
  
• Marine and offshore installations
  

They are particularly preferred where pipe alignment and frequent maintenance are important.

Conclusion

The Stainless Steel Lap Joint Flange weight chart with dimensions and pressure ratings is an essential reference for engineers, contractors, and procurement teams. Knowing the correct weight and pressure class ensures safe system design, accurate costing, and efficient installation. By combining corrosion-resistant stainless steel with a flexible flange design, lap joint flanges offer a reliable and cost-effective solution for modern industrial piping systems.