SS 304 Pipe Weight Chart: ASTM A312 and ASME B36.19M Data

SS 304 Pipe Weight at a Glance

The weight of an SS 304 pipe varies with diameter, schedule and length. Small-diameter thin-wall pipe weighs roughly 0.36 kg/m, while large heavy-wall pipe can exceed 73 kg/m. For example, a 1-inch Schedule 40 pipe weighs approximately 2.54 kg/m, and a 4-inch Schedule 40 pipe weighs approximately 16.35 kg/m. The weight data in this chart is based on the nominal dimensions of ASME B36.19M for stainless steel pipe, which matches the OD and wall-thickness series used for ASTM A312 seamless and welded pipe.

SS 304 Pipe Weight Chart (NPS 1/8 – 12 Inch)

Weights are calculated for annealed 304 stainless steel with a density of 7.93 g/cm³. Schedule designations follow ASME B36.19M: 5S, 10S, 40S and 80S.

How to Calculate SS 304 Pipe Weight

For any pipe, the theoretical weight is the volume of the steel wall multiplied by density. The practical formulas are:

Metric: W = (OD − WT) × WT × 0.02491, where OD is the outer diameter in mm and WT is the wall thickness in mm, giving weight in kg/m.

Imperial: W = (OD − WT) × WT × 10.69, where OD and WT are in inches, giving weight in lb/ft.

The constants incorporate the density of austenitic stainless steel, about 7.93 g/cm³. Multiply the unit weight by the pipe length to obtain the total weight for logistics and budgeting.

304 Pipe versus 304 Tube: A Common Procurement Mistake

A frequent error in procurement is confusing pipe and tube dimensions. SS 304 pipe is specified by NPS and Schedule; for example, a 1-inch Schedule 40 pipe has an actual outer diameter of 33.4 mm. SS 304 tube is specified by actual outer diameter and wall thickness; a 1-inch tube has an actual outer diameter of 25.4 mm. Always confirm whether the project documents call for NPS-based pipe or OD-based tube, because mixing the two can cause errors of 20% to 30% in weight and logistics planning.

Pressure Rating of SS 304 Schedule 40 Pipe

Pressure ratings depend on diameter, wall thickness and temperature. As an indicative reference at about 38 °C, small-diameter Schedule 40 pipe can be rated above 2,000 psi, a 2-inch pipe is typically rated around 1,030 to 1,250 psi, and a 4-inch pipe around 1,000 psi. Rated pressures decrease as the service temperature rises, so the design code calculation based on the actual working temperature must always be verified before specification.

HSN Code and Trade Classification

In international trade, SS 304 seamless pipe falls under HSN code 73044100 for cold-drawn or cold-rolled seamless tubes, and welded stainless steel tube falls under 73064000. Both are classified within Chapter 73, Articles of Iron or Steel. The correct HSN code affects duty rates and import documentation, and should be confirmed with the customs authority of the destination country.

FAQs

What is the weight of a 1-inch SS 304 Schedule 40 pipe?

A 1-inch Schedule 40 pipe has an OD of 33.40 mm and a wall of 3.38 mm, giving a unit weight of approximately 2.54 kg/m or 1.71 lb/ft.

How do I convert pipe weight from kg/m to lb/ft?

Multiply the value in kg/m by 0.6715 to obtain lb/ft, or use the imperial formula with dimensions in inches. For example, 2.54 kg/m multiplied by 0.6715 equals about 1.71 lb/ft.

Which schedule should I choose for high-pressure service?

Higher schedules such as 80S or 160 provide thicker walls and therefore higher pressure ratings for a given diameter. The required schedule is determined by the design pressure, temperature and allowable stress in the applicable design code, not by weight alone.

Why do the chart values differ from measured pipe weight?

The chart gives theoretical weight based on nominal dimensions and standard density. Actual weight varies with the manufacturing tolerance of wall thickness and OD, the exact alloy density and surface condition, so measured weight can differ slightly from theoretical values.

What is the difference between Schedule 40 and Schedule 40S?

Schedule 40 is used for carbon steel pipe and Schedule 40S for stainless steel pipe. For sizes up to about 10 inches the wall thicknesses are nearly identical, but the S designation follows the stainless steel dimensioning rules of ASME B36.19M.

Does welded 304 pipe weigh the same as seamless?

Yes, for the same NPS, schedule and length, seamless and welded pipe have essentially the same theoretical weight because the outer dimensions and wall thickness are identical. The difference lies in manufacturing route, not in weight.