What Material Is STPG370 Pipe
STPG370 pipe is made of carbon steel. It is a specific grade defined by the Japanese Industrial Standard JIS G 3454 for carbon steel pipes intended for pressure service. STPG indicates seamless steel tubes for pressure purposes, and 370 refers to the specified minimum tensile strength of 370 MPa. It is chemically similar to grades such as ASTM A53 Grade B or ASTM A106 Grade B, and the same size range and testing principles apply.
The Three Types of Steel Pipe
Steel pipes are primarily categorized by manufacturing method. Seamless pipe is made by piercing a solid billet and drawing it into a hollow tube, with no welded seam, generally higher strength, and use in high-pressure applications. Welded pipe with a longitudinal seam is made by rolling steel plate or strip into a cylinder and welding the seam straight along its length, with common types including electric resistance welded, submerged arc welded, and laser welded pipe, used for lower pressure and structural service. Spiral welded pipe is formed from steel coil with a continuous helical weld, often used for large-diameter pipes such as water transmission mains and piling.
What Is CHS Steel Pipe
CHS stands for circular hollow section. It refers to steel pipe with a circular cross-section used primarily for structural applications such as columns, trusses, frames, and handrails, rather than fluid conveyance under pressure. CHS pipes are typically cold-formed and welded, and dimensioned by outside diameter and wall thickness. CHS is the common term in Europe, Australia, and Asia; in North America the equivalent term is HSS (hollow structural section) round.
What Is NPS Steel Pipe
NPS stands for nominal pipe size, a North American standard sizing system used to designate the diameter of a pipe. It is not a material or a type of pipe. The NPS number does not equal the actual outside diameter in inches, especially for sizes NPS 1/8 to NPS 12, where the outside diameter is standardized and larger than the NPS number. For sizes NPS 14 and above, the NPS number equals the actual outside diameter in inches. Pipes conforming to ASME B36.10M or B36.19M are dimensioned using the NPS system.
How to Tell NPS vs NPT
NPS refers to the size designation of the pipe itself, its diameter. NPT stands for national pipe taper, a standard for tapered threads used on the ends of pipes, fittings, and valves to create pressure-tight seals. NPS has nothing to do with taper; NPT threads have a defined taper of 3/4 inch per foot and a 60-degree flank angle, sealing by the wedging action of the tapered threads often aided by thread sealant. In short, NPS tells you how big the pipe is; NPT tells you what kind of threads are on its ends.
Frequently Asked Questions
Q: What does STPG370 mean?
A: STPG indicates seamless steel tubes for pressure purposes per JIS G 3454, and 370 is the minimum tensile strength of 370 MPa.
Q: What is the equivalent of STPG370?
A: It is chemically and mechanically similar to ASTM A53 Grade B and A106 Grade B carbon steel pipe.
Q: What are the three types of steel pipe?
A> By manufacturing method: seamless, longitudinal welded (ERW/SAW/Laser), and spiral welded.
Q: What is the difference between CHS and HSS?
A: They are the same concept of circular hollow sections; CHS is the common term in Europe, Australia, and Asia, while HSS is used in North America.
Q: Is NPS the actual pipe diameter?
A: No, for sizes up to NPS 12 the outside diameter is larger than the NPS number; for NPS 14 and above the NPS number equals the OD in inches.
Q: What is the difference between NPS and NPT?
A: NPS is the nominal pipe size of the pipe body, while NPT is the tapered thread standard for pressure-tight connections on pipe ends and fittings.
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