What You Need to Know About General Structural Steel (SS Material)

Key Takeaways

• General structural steel is cheap, highly machinable, and excellent for welding and sheet metal fabrication.

• It is weak in strength and corrosion resistance and cannot be heat-treated.

• It is best for non-critical, general-purpose applications.

General Structural Steel (SS Material) Overview

General structural steel (SS Material) is widely used type of low-carbon steel, containing about 0.15 to 0.2% carbon. Although it is not the strongest type of steel, it is inexpensive, readily available, and easy to machine, making it suitable for a broad range of applications across a wide range of industries, including bridges and ships and parts for various kinds of machines.

Compared to SC material, SS has a lower carbon content, resulting in lower strength. The number following "SS" indicates the minimum guaranteed tensile strength. Because the composition specifications are not very strict, slight variations in properties can occur between production lots.

Characteristics of General structural steel (SS Material)

Excellent Machinability

With its low carbon content, SS material is softer than other steels, which makes it highly machinable. It is ideal for sheet metal processing, laser cutting, and other manufacturing methods, offering flexibility in design and application.

Low Corrosion Resistance

Because SS steel has limited corrosion resistance, it is often paired with surface treatments such as plating or painting. In cases where protection is less critical, black-scaled steel with a natural oxide layer may be used, though it lacks precise dimensional accuracy. For parts processing, polished steel with a clean surface is generally preferred.

High Versatility

SS material is easy to source, cost-effective, and versatile. While it has lower strength than SC steel, it offers superior weldability. For applications where extreme strength is not required, SS material is often the most practical option.

Flexible Composition Standards

The chemical composition of SS steel is not strictly regulated, except for upper limits on harmful elements like phosphorus and sulfur. Minimum tensile strength requirements apply, but slight quality differences can appear between production batches.

Poor Heat Treatability

Since SS material has a carbon content below 0.3%, it cannot be strengthened through heat treatment. However, this also means its strength properties remain stable during processing, making the material easier to handle.

Excellent Weldability

SS steel does not experience major hardness changes under heat, so it can be welded reliably. For components exposed to high stress, rolled steel designed for welded structures may be more suitable, but for general construction, SS material provides sufficient performance.

Step Up Your Project with Yumoto Electric

Yumoto Electric delivers high-quality components fast, worldwide. We provide precision machining for a wide range of metals using milling, turning, and specialized metal processing. We have experience with over 200 materials including aluminum alloys, stainless steel, molybdenum, and titanium. 

If you’re unsure about material selection or machining methods, we offer complimentary consultations to help optimize your design and production. For any questions, please feel free to contact us.