Steel Square Bars

Carbon steel square bar refers to square bars made of carbon steel, while Mild steel square bar refers to those made of mild steel. 

The main differences between them are as follows:

Composition

- Carbon steel square bar: Carbon steel is mainly an alloy of iron and carbon. Its carbon content can vary within a certain range, and it may also contain small amounts of elements such as silicon, manganese, sulfur, and phosphorus. According to the different carbon contents, carbon steel can be divided into low-carbon steel, medium-carbon steel, and high-carbon steel.

- Mild steel square bar: Mild steel square bar is a low carbon steel bar that has the cross-section of a square. Mild steel square bars are usually hot-rolled and are ideal for various applications like structural, general fabrication, manufacturing and even industrial maintenance repairs. With its high strength and versatility, mild steel square bars can be drilled, welded, machined and cut to suit a wide range of general engineering and manufacturing applications.

Properties

- Strength

- Carbon steel square bar: Due to its wide range of carbon contents, the strength also has a relatively wide variation range. High-carbon steel has relatively high strength and can be used for structural components that bear large loads. Medium-carbon steel has moderate strength. Low-carbon steel has relatively low strength.

- Mild steel square bar: It has relatively low strength but good toughness and ductility, and is easy to be processed and formed, such as bending and stamping.

- Hardness

- Carbon steel square bar: High-carbon steel has relatively high hardness and good wear resistance. Low-carbon steel has relatively low hardness.

- Mild steel square bar: It has relatively low hardness, which facilitates mechanical processing operations such as cutting and drilling.

- Toughness

- Carbon steel square bar: As the carbon content increases, the toughness will gradually decrease. High-carbon steel is relatively brittle, while low-carbon steel has better toughness.

- Mild steel square bar: It has better toughness and is not easy to break when subjected to impact or deformation.

Applications

- Carbon steel square bar:

- High-carbon steel square bars can be used to manufacture tools and parts that require high hardness and high strength, such as cutting tools, springs, and molds.

- Medium-carbon steel square bars are suitable for manufacturing some mechanical parts, such as gears and shafts.

- Low-carbon steel square bars have similar applications to mild steel square bars and are used in occasions where the strength requirement is not high but the formability requirement is good.

- Mild steel square bar: Uses of mild steel square bar include structural and construction applications, manufacturing, transportation equipment, general fabrication, industrial maintenance, agricultural implements and decorative applications.

Grades

- Carbon steel square bar: Q195,Q235,Q345B,Q420 Q460 S420 S460 St37,St52,St35A36 A105 SS400 S235JR S275JR S355JR S235J2 S275J2 S355J2 S235J0 S275J0 S355J01008 1010 1015 1018 1020 1035 1045 1050 1060 S20CS35C S45C 4130 4140 4135 SCM430 SCM440 SCM435 8620H 4340 9840 4437 SNCM220 SNCM8 1213 1215 1117 1144 1132 12L14 12L13 11SMN30

- Mild steel square bar: Two of the common grades of mild steel square bars are EN10025 S275 and BS4360 Grade 43A. EN10025 S275 is a popular mild steel grade suitable for various general engineering and structural applications. As a low carbon steel specifications, EN10025 S275 provides low strength with good machinability and can be easily welded. Mild steel grade S275 is used widely in the construction, industrial maintenance and manufacturing industries.

Mild steel grade BS4360 Grade 43A is another widely used carbon structural steels, which is suitable for a large number of engineering applications. It is cheaper than most other mild steel grades, which makes it suitable for different applications such as building and machinery constructions that do not require wear-resistance and high strength.