Low Carbon Steel Pipe Specification Guide

What Is Low Carbon Steel Pipe?

Low carbon steel pipe, also known as mild steel pipe (MS pipe), is a type of carbon steel pipe manufactured from steel with a relatively low carbon content, typically less than 0.25%–0.30% carbon.
Due to its low carbon content, low carbon steel has excellent ductility, weldability, and machinability. These characteristics allow the material to be easily formed, cut, welded, and fabricated into different pipe shapes and sizes.
Low carbon steel pipes are widely used in industrial piping systems, construction projects, water transportation, mechanical structures, and general engineering applications because they provide a good balance between strength, durability, and cost.
In the steel industry, the terms low carbon steel pipe and mild steel pipe (MS pipe) are often used interchangeably. However, there is a slight difference:
Low carbon steel refers to a material classification based on carbon content.
Mild steel pipe (MS pipe) is a commercial term commonly used by manufacturers, suppliers, and buyers.

Most MS pipes are produced using low carbon steel grades.

Is MS Pipe the Same as Low Carbon Steel Pipe?

Yes, in most industrial applications, MS pipe and low carbon steel pipe refer to the same type of steel product.
Mild steel is called "mild" because it contains a low amount of carbon, which makes the steel softer and easier to process compared with medium and high carbon steel.
The main difference is that:

Item	Low Carbon Steel Pipe	MS Pipe
Definition	Material classification	Commercial product name
Carbon Content	Usually ≤0.25–0.30%	Usually ≤0.25–0.30%
Weldability	Excellent	Excellent
Formability	Excellent	Excellent
Cost	Economical	Economical
Common Uses	Industrial piping, structures	Water pipes, fabrication, construction

For engineering selection, buyers usually focus on the pipe standard, grade, size, wall thickness, and application requirements rather than the terminology.

Characteristics of Low Carbon Steel Pipe（MS Pipe）

Low carbon steel pipes remain one of the most widely used industrial piping materials because they provide an ideal combination of mechanical performance, manufacturing efficiency, and cost-effectiveness.

Excellent Weldability
One of the biggest advantages of low carbon steel is its outstanding weldability. Because of its relatively low carbon content, the material has a much lower risk of cracking during welding than medium- or high-carbon steels. Most fabrication projects can be completed without extensive preheating or post-weld heat treatment, reducing both production time and overall costs.

High Ductility and Formability
Low carbon steel can be bent, rolled, stamped, expanded, and cold-formed with minimal risk of fracture. These characteristics make it suitable for manufacturing structural components, pipe fittings, automotive parts, and customized fabrication projects.

Good Machinability
The material performs well during cutting, drilling, threading, milling, and turning operations. Manufacturers can easily process low carbon steel into complex components while maintaining dimensional accuracy and consistent quality.

Reliable Strength
Although it does not achieve the hardness of higher-carbon steels, low carbon steel provides sufficient tensile and yield strength for most construction, transportation, mechanical, and industrial piping systems.

Cost-Effective Solution
Compared with stainless steel and alloy steel, low carbon steel offers significantly lower material costs while still delivering dependable mechanical performance. Its wide availability and straightforward manufacturing process further reduce procurement and fabrication expenses.

Common ASTM and API Standards for Low Carbon Steel Pipe

Low carbon steel pipes are manufactured under various international standards depending on the intended application. Each specification defines requirements for chemical composition, mechanical properties, dimensions, testing, and quality control.

Standard	Product Type	Typical Applications
ASTM A53	Welded & Seamless Pipe	Water, gas, structural applications
ASTM A106 Grade B	Seamless Pipe	High-temperature pressure service
ASTM A179	Heat Exchanger Tube	Boilers and heat exchangers
ASTM A192	Boiler Tube	High-pressure boilers
API 5L Grade B	Line Pipe	Oil and gas pipeline transportation
ASTM A500	Structural Tube	Buildings, bridges, machinery

Selecting the appropriate standard depends on operating pressure, temperature, corrosion conditions, and industry requirements. For pressure piping systems, compliance with ASTM or API specifications ensures reliable performance and international acceptance.

Low Carbon Steel Pipe Manufacturing Process

Low carbon steel pipes are produced using advanced manufacturing techniques to ensure consistent dimensions, mechanical properties, and surface quality. Depending on the pipe type, manufacturers typically use seamless or welded production methods.

The general manufacturing process includes:
1.High-quality steel billet or steel coil preparation
2.Heating and piercing (for seamless pipes) or forming and welding (for welded pipes)
3.Hot rolling or cold drawing
4.Heat treatment, when required
5.Sizing and straightening
6.Non-destructive testing and hydrostatic testing
7.Surface finishing, marking, and packaging
Modern production lines also employ ultrasonic testing, eddy current inspection, dimensional measurement, and chemical composition analysis to ensure every pipe meets the required international standards.

Standard Sizes and Dimensions of Low Carbon Steel Pipe

Low carbon steel pipes are manufactured in a wide range of sizes to meet different engineering and industrial requirements. Depending on the manufacturing standard, dimensions are typically specified by nominal pipe size (NPS), outside diameter (OD), wall thickness (Schedule), and length.

Parameter	Typical Range
Outside Diameter (OD)	10.3 mm – 1219 mm (1/8" – 48")
Wall Thickness	SCH 10, SCH 20, SCH 40, SCH 80, SCH 160
Length	5.8 m, 6 m, 11.8 m, 12 m or customized
Manufacturing Type	Seamless, ERW, LSAW, SSAW
End Type	Plain End (PE), Beveled End (BE), Threaded End (TE)

The appropriate size should be selected according to operating pressure, flow requirements, installation conditions, and applicable design codes.

Low Carbon Steel Pipe Dimensions

Low carbon steel pipes are available in various sizes, wall thicknesses, and schedules according to international standards such as ASME B36.10M. Common pipe schedules include SCH 5, SCH 10, SCH 40, SCH 80, and SCH 160.

Nominal Pipe Size (NPS)	Outside Diameter (OD)	Common Wall Thickness	Available Schedules
1/2"	21.3 mm	2.8–3.7 mm	SCH 5–SCH 80
1"	33.4 mm	3.4–4.6 mm	SCH 5–SCH 80
2"	60.3 mm	3.9–8.7 mm	SCH 5–SCH 160
4"	114.3 mm	6.0–11.1 mm	SCH 10–SCH 160
6"	168.3 mm	7.1–14.3 mm	SCH 10–SCH 160
8"	219.1 mm	8.2–18.3 mm	SCH 10–SCH 160
12"	323.9 mm	10.3–25.4 mm	SCH 10–SCH 160

For detailed dimensions and weight information, please refer to our Schedule 40 Steel Pipe Size Chart.

Mechanical Properties of Low Carbon Steel Pipe

The mechanical properties of low carbon steel pipe vary depending on the manufacturing standard and grade. Typical values are shown below:

Property	Typical Value
Tensile Strength	330–550 MPa
Yield Strength	205–350 MPa
Elongation	20–35%
Hardness	120–180 HB
Weldability	Excellent

Although low carbon steel does not have the highest hardness, its combination of strength and ductility makes it suitable for many piping and structural applications.

FAQ

1. What is low carbon steel pipe?
Low carbon steel pipe is a steel pipe manufactured from steel containing a low amount of carbon, generally less than 0.25%–0.30%. It offers excellent weldability, ductility, and machinability.

2. Is MS pipe the same as low carbon steel pipe?
Yes, in most applications MS pipe (mild steel pipe) is made from low carbon steel. The difference is that low carbon steel describes the material classification, while MS pipe is a commercial product term.

3. What is the carbon content of mild steel pipe?
Mild steel pipe usually contains less than 0.25% carbon, although some specifications allow carbon content up to approximately 0.30%.

4. What are the common standards for low carbon steel pipe?
Common standards include:
ASTM A53
ASTM A106
API 5L
ASTM A500
ASTM A179
The correct standard depends on application requirements such as pressure, temperature, and service environment.

5. Is low carbon steel pipe suitable for welding?
Yes. Low carbon steel pipe has excellent weldability because the low carbon content reduces the risk of weld cracking and improves fabrication performance.

6. What are the main applications of MS pipe?
MS pipes are widely used in:
Water supply systems
Construction structures
Fire protection systems
Industrial piping
Machinery fabrication
Agriculture irrigation