How to Choose The Low Carbon Steel for Mild Steel Pipe?

Mild steel pipe, a type of carbon steel pipe, is made by rolling or cold drawing low carbon steel (carbon content 0.10%-0.25%). Due to its low carbon content and relatively low hardness, it is also known as "mild steel" pipe. MS pipe has excellent plasticity, toughness, weldability, and processability, making it widely used in building structures, automotive manufacturing, machining, petrochemicals, and other fields.

When selecting mild steel pipe material, it is necessary to comprehensively evaluate the mechanical properties, corrosion resistance, and processability requirements of the application, and determine the appropriate steel grade based on relevant standards.

Overview of Low Carbon Steel

Low carbon steel is a type of steel with a low carbon content, typically no more than 0.25%. It has the following typical properties:

1. High machinability

Easy to cold bend, cut, and stamp.

2. Good toughness

Excellent impact resistance at both low and room temperatures.

3. Good weldability

Suitable for a variety of welding methods, including arc welding and gas welding.

4. Low cost

Compared to alloy steel, it has lower raw material and processing costs.

Low carbon steel has a wide range of applications, including construction, automotive, and steel structures.

Mechanical Properties of Low Carbon Steel

1. Tensile strength

300-500 MPa, lower than medium- and high-carbon steels (e.g., 45 steel has a tensile strength of ≥600 MPa).

2. Low hardness

With a Brinell hardness of approximately 120-150 HB, it requires carburizing for use in wear-resistant parts.

Comparison of Low Carbon Steel and Other Carbon Steels

Low Carbon Steel Material Classification

1. Ordinary carbon structural steel (such as Q195, Q215, Q235)

Carbon content not exceeding 0.25%, moderate strength, good plasticity, commonly used for manufacturing simple parts.

2. High-Quality carbon structural steel (such as No. 20 and No. 25 steel)

Slightly higher carbon content, higher strength and good toughness, suitable for parts bearing moderate loads.

3. Low-Alloy high-strength steel (such as Q345)

Contains a certain amount of other alloying elements (such as chromium and molybdenum). Commonly used for manufacturing high-demand industrial structures such as large machinery and equipment, automobiles, and bridges.

4. Low-carbon galvanized steel (such as Q235 with hot-dip galvanizing)

This type of steel has a zinc coating on its surface, offering high corrosion resistance and is commonly used in the manufacture of corrosion-resistant parts.

Selection Principles for Mild Steel Pipes

When selecting mild steel pipes, consider the following aspects:

1. Mechanical performance requirements

Tensile strength: Generally 300-500 MPa;

Elongation: ≥20% (important for forming).

For example, Q235 steel has a tensile strength of 375-500 MPa and an elongation of ≥26%, making it suitable for general structural parts.

2. Application compatibility

For pipes used in building structures: Q215 and Q235 are preferred, as they meet static load-bearing requirements and offer excellent economical performance.

For automotive panels: For high formability and surface quality, 08Al steel (elongation ≥30%) is an option.

For pipelines: For corrosion resistance, galvanized mild steel pipe (hot-dip galvanizing layer thickness ≥85μm) is an option.

3. Processing compatibility

Cold-rolled mild steel pipe (such as SPCC): Features a smooth surface and is suitable for stamping.

Hot-rolled mild steel pipe (such as Q195): Offers excellent toughness and weldability, making it suitable for structural welding.

4. Standards and certifications

Chinese Standards: GB/T 700 (carbon structural steel), GB/T 3091 (welded steel pipe), GB/T 8162 (seamless steel pipe for structures), GB/T 8163 (seamless steel pipe for fluid transportation).

International Standards: ASTM A53, ASTM A106, EN 10219, EN 10255.

For export or special projects, ensure that MS pipe meets the certification requirements of the customer's location.

Summary

This article introduces low-carbon steel, the material used for mild steel pipe. Due to its excellent formability, weldability, and cost-effectiveness, mild steel pipe is widely used in engineering construction, machinery manufacturing, the automotive industry, and other fields. When selecting materials, it's important to consider not only mechanical properties and cost, but also the application environment, processing technology, and relevant standards to select the most suitable low-carbon steel grade and surface treatment. Proper material selection not only increases the service life and safety of low carbon steel pipes, but also reduces subsequent maintenance costs, resulting in higher overall benefits for engineering and production.