Threaded Carbon Steel Pipes

Threaded Carbon Steel Pipes

In industrial fluid transportation, building water supply and drainage, and various piping systems, threaded carbon steel pipes are a fundamental and crucial connecting component. It refers to the standardized helical thread cut into the outer side of one end of a carbon steel pipe through specialized machining (threading), allowing it to be screwed into threaded pipe fittings (such as elbows, tees, valves, or unions) like a screw, thus achieving a tight connection between pipes.

I. Core Features and Advantages
The superior performance of threaded carbon steel pipes stems from the combination of its materials and structure:

1. High Strength and High Pressure Bearing Capacity: Carbon steel itself possesses high mechanical strength and hardness, enabling threaded joints to withstand high internal fluid pressure and external mechanical loads without easily deforming or breaking, making them particularly suitable for industrial high-pressure piping systems.

2. Good Durability and Long Service Life: After appropriate rust-proofing treatment (such as galvanizing, oiling, or painting), carbon steel (usually Q235 steel or 20# steel) possesses good corrosion resistance and wear resistance, ensuring the stability and reliability of the connection point under long-term use.

3. Robust Connection and Reliable Sealing: The tight engagement of the threads, combined with sealing materials (such as PTFE tape, hemp fiber, or pipe thread sealant), forms a rigid interface with excellent airtightness and watertightness, effectively preventing leakage.

4. Standardization and Universality: The threads typically conform to national or international standards (such as China’s GB/T 7306, the UK’s BSPT, and the US’s NPT), offering strong interchangeability. This means that pipes and fittings conforming to the same standard, regardless of manufacturer, can achieve a perfect fit, greatly facilitating procurement, construction, and maintenance.

II. Main Processing and Types The processing of external threads on carbon steel pipes primarily utilizes a specialized tool called a “threading machine.” Based on the thread shape, it is mainly divided into two types:
**Conical Pipe Threads (NPT/BSPT):** The threads are tapered; as the thread is screwed in, the fit between the threads becomes increasingly tight. Sealing is mainly achieved through the deformation of the thread itself, belonging to the “dry seal” thread category.

Cylindrical Pipe Threads (BSPP): The threads are cylindrical, and the seal is mainly achieved by pressing a sealing ring (such as an O-ring or gasket) against the end face. The threaded portion primarily serves for connection and fastening.

III. Application Scenarios Carbon steel pipe threads have extremely wide applications, covering almost all fields requiring robust pipe connections:

Construction: Fire sprinkler systems, heating pipelines, and main water supply pipelines in buildings.

Industrial: Process pipelines in petroleum, chemical, and pharmaceutical plants; compressed air systems; water cooling and oil pipelines in mechanical equipment.

Municipal Engineering: Connections for some water and gas pipelines (corrosion protection is required).

IV. Precautions When using these threads, two points must be noted: First, the machined threads must be treated with anti-corrosion measures to prevent rusting from the threaded area onwards; second, moderate force should be applied when tightening, and the correct sealing material should be used. Over-tightening may cause the threads to strip or the pipe fittings to crack.

In conclusion, carbon steel pipes with external threads, with their robust, durable, and reliable characteristics, have become an indispensable “backbone” in pipeline engineering, silently supporting the smooth flow of modern industry and life.