[Carbon #1] SS400 (JIS): The "Dollar" of the Steel World

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 "If steel were a currency, SS400 would be the US Dollar."

It is the most traded, most used, and most standard material in the global market. Often referred to as "Mild Steel," it is the go-to solution for projects where high tensile strength is not critical, but Weldability and Cost-Effectiveness are essential.

1. The Global Reality: SS400 vs Q235B

Textbooks define JIS SS400 and GB Q235B separately. But in the actual global market, they are Practical Equivalents.

💡 Trader's Insight

Since massive steel mills operate on high-volume production, creating a custom chemical mix for SS400 is inefficient. Therefore, Chinese Q235B is widely accepted as SS400 worldwide, provided it meets the strength requirements.

Grade Tensile Strength Yield Strength
SS400 (JIS) 400 ~ 510 MPa Min 245 MPa
Q235B (China) 370 ~ 500 MPa Min 235 MPa

Note: Smart buyers focus on Physical Properties rather than demanding a strict chemical match.

2. ⚠️ Critical Warning: Heat Treatment

I see this mistake too often. Please DO NOT attempt induction hardening (Quenching) on SS400.

  • Why? Carbon content is too low (approx 0.15~0.20%). It will not harden properly.
  • The Solution: If you need hardness or wear resistance (e.g., for gears or shafts), you MUST upgrade to S45C (AISI 1045) or SCM440.

3. Where is it Used?

  • Construction: H-Beams, Channels, Angles.
  • Civil Engineering: Bridges, Oil Tanks, Ship Parts.
  • Machinery: Base plates and non-critical support frames.

Expert Verdict: The Budget Champion

We highly recommend SS400 for construction companies and manufacturers looking for the most economical and versatile steel solution.
It is the "Rice" of the industry—basic, essential, and everywhere.

⚖️ Disclaimer & Privacy Notice:
The information provided on Global Steel Insight is for general informational and educational purposes only. It does not constitute professional financial, legal, or engineering advice. Steel prices, standards, and market conditions are subject to change without notice. We are not liable for any losses or damages arising from the use of this information. Always consult with a qualified professional before making business decisions.

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