Mild Steel Pipe Standards

What is Mild Steel Pipe?

Mild steel pipe (MS pipe full form) is a type of structural steel pipe made of mild steel. The main chemical composition of MS pipe is iron (Fe) and a small amount of carbon (C), with a carbon content typically between 0.05% and 0.25% (mass fraction). What is the effect of such a low carbon content? Just 1% carbon is enough to give steel properties such as strength, ductility, and durability. It is precisely because of this carbon content that mild steel pipe performs well in heavy-duty applications subjected to enormous physical stresses.

Furthermore, they are easy to manufacture and can withstand cold and hot working well. Although their strength is still lower than that of high carbon steel pipes with a carbon content of up to 3%, their strength can be enhanced through carburizing processes. Mild steel's main component is iron, therefore it has strong magnetic properties. Due to its availability, it has become one of the most widely used industrial materials.

Properties of Mild Steel Pipes

1. Mechanical Strength

Mild steel pipes possess excellent mechanical strength. Their high tensile strength (approximately 330–560 MPa) allows them to withstand enormous loads.

2. Corrosion Resistance

While not completely rust-free, mild steel pipes exhibit a degree of corrosion resistance, especially after protective coating treatments such as galvanizing or painting. This characteristic extends their service life to 10–25 years.

3. Versatility

The elongation of mild steel is typically 20%–30%.

Due to its ductility and weldability, MS pipes can be bent, cut, and formed into various shapes to meet a wide range of construction, machinery, and industrial applications.

4. Durability

Mild steel pipes possess high durability, operating stably under harsh conditions without significant wear.

This makes them particularly suitable for applications requiring frequent exposure to mechanical stress.

5. Cost-Effectiveness

Compared to high-carbon steel or alloy steel, mild steel pipes are more affordable, making them an ideal choice for large-scale projects, while offering comparable performance and durability.

Mild Steel Pipe Standards

Each country has its own method of classifying metal alloys based on their properties and applications. Common steel pipe grades cover standards from the United States, India, the United Kingdom, Europe, Japan, and Australia. Among these, the American ASTM standard is the most widely used classification system.

MS Pipe Standards Chart

Applications of MS Pipes in Different Standards

1. American Standards (ASTM / API)

ASTM A53

This mild steel alloy has low rigidity but excellent machinability. It is commonly used for structural components and domestic piping.

ASTM A120

General-purpose, economical standard for low-pressure liquid transportation.

ASTM A795

Standard for black and galvanized welded steel pipes for fire protection systems. Usually available in black galvanized form. Due to its high-pressure resistance, it is commonly used in industrial, mechanical, and HVAC applications.

ASTM A500

Cold-formed welded structural pipe, used for the manufacture of square and rectangular tubes.

API 5L

Standard for carbon steel pipes for oil and gas pipelines.

ASTM A135

A135 mild steel has excellent temperature resistance, making it suitable for fire protection. It is also used for transporting gases, steam, and other liquids.

ASTM A523

Used for high-pressure piping and cable laying. It can be heat-treated and coated with anti-corrosion coatings.

2. Indian Standards (IS/ISO)

IS 1239

IS 1239 (Part 1) applicable to black and galvanized steel pipes for water, gas, steam, and air transport.

IS 4270/IS 9295

Applicable to large-diameter welded steel pipes and pressure piping.

IS 1161

Steel pipes for structural and mechanical applications.

IS 3589

Welded steel pipes suitable for water and gas transport.

IS 3601

General purpose carbon steel pipes.

IS/ISO 3183

Standard for pipelines used in the oil and gas industry.

3. British Standards (BS)

BS 1387

Black and galvanized welded steel pipes, commonly used in building and water systems.

BS 1775 / BS 1139

Steel pipes for scaffolding and building supports.

BS 534 / BS 6363

Water and sewage transport piping.

BS 3601

Carbon steel pipes for general structural and engineering applications.

4. European Standards (EN)

EN 10224/EN 10217

Welded steel pipes for pressure piping and fluid transport.

EN 10255

A versatile pipe grade suitable for welding and threading.

EN 10219

Cold-formed welded structural steel sections (square and rectangular tubes).

EN 10296

Steel pipes for mechanical and general engineering applications.

5. Japanese Standards (JIS)

JIS G 3452

Steel pipes for water, gas, and steam transport.

JIS G 3444

Carbon steel pipes for general structural applications. Covers seamless and welded mild steel pipes used in civil engineering applications.

JIS G 3454 / JIS G 3455

Steel pipes for high-temperature pressure piping and steam piping.

6. Australian Standards (AS)

AS 1074

Black and galvanized steel pipes for water and gas transmission.

AS 1163

Cold-formed welded structural steel (equivalent to EN 10219).

AS 1450

High-strength mild steel structural pipes.

Differences Between ASTM, EN, JIS, IS, and BS

1. ASTM (American Society for Testing and Materials)

One of the most widely used standards systems globally, emphasizing uniformity in chemical composition, mechanical properties, and manufacturing processes.

2. EN (European Standard)

Focuses on dimensional tolerances and weldability, commonly used in construction and mechanical engineering in the European Union.

3. JIS (Japanese Industrial Standard)

Requires extremely high quality control, suitable for high-precision manufacturing industries.

4. IS (Indian Standard)

Highly compatible with international standards, commonly used for water pipes, structural pipes, and gas transmission.

5. BS (British Standard)

An earlier industrial standard, widely used in construction, scaffolding, and low-pressure systems.

FAQ

1. Which Standard of Mild Steel Pipe is Most Common?

In the international market, ASTM A53 and EN 10255 are the two most widely used MS pipe grades.

2. What is the Difference Between EN 10219 and EN 10210 Pipes?

EN 10219: Cold-formed welded structural steel standard, commonly found in square and rectangular tubes.

EN 10210: Hot-formed structural steel standard, with higher mechanical properties, suitable for structures bearing high loads.

3. How to Identify Which Standard a Mild Steel Pipe Conforms to?

Check the pipe markings:

Standard number (e.g., ASTM A53 / EN 10255)

Grade (e.g., Grade A, B, C)

Specifications (OD×WT)

Manufacturer's name and Heat No.

This information is usually marked on the pipe surface in the form of inkjet printing or engraving.

Summary

Mild steel pipes are among the most commonly used steel pipe types globally due to their excellent machinability, robust structural properties, and economic efficiency. Different countries regulate them through standards such as ASTM, EN, JIS, IS, BS, and AS to ensure consistency and safety in their structure, transportation, and industrial applications.