Chemical element composition of Chinese grade hot-rolled Q355C low-alloy high-strength structural steel
Q355C Approximate Grade Lookup Table

Table 1  Chemical Composition

Grade Chemical Composition（Quality Fraction） / %
Steel Grade Quality Grade Cᵃ Si Mn Pᶜ Sᶜ Nbᵈ Vᵉ Tiᵉ Cr Ni Cu Mo Nᶠ B
Thickness
≤40ᵇ ＞40 ≤
≤
Q355 C 0.2 0.22 0.55 1.6 0.03 0.03 - - - 0.3 0.3 0.4 - 0.012 -
a For structural steel sections with a nominal thickness greater than 100mm, the carbon content can be determined through negotiation between the supplier and the buyer.
b For steel with a nominal thickness greater than 30mm, the carbon content shall not exceed 0.22%.
c For structural steel and bars, the upper limit for phosphorus and sulfur content can be increased by 0.005%.
d The maximum percentage for Q390 and Q420 can reach 0.07%, while for Q460 it can reach 0.11%.
e Up to0.2%
f If the acid-soluble aluminum (Als) content of the steel is not less than 0.015% or the total aluminum content is not less than 0.02%, or if other oxygen-fixing alloying elements are added, the nitrogen content is not limited, and the oxygen-fixing elements should be specified in the quality certificate.
g Applicable only to structural steel and bars

Table 2  Tensile properties

Grade Upper yield strength ReHᵃ／MPA
≥		 Tensile strength Rm／MPA KV2 ( J)
Steel Grade Quality
Grade		 Nominal thickness or diameter／ｍｍ 0℃
≤16 ＞16~40 ＞40~63 ＞63~80 ＞80~100 ＞100~150 ＞150~200 ＞200~250 ＞250~400 ≤100 ＞100~150 ＞150~250 ＞250~400 Vertical Horizontal
Q355 C 355 345 335 325 315 295 285 275 — 470~630 450~600 450~600 — 34 27
ａ:When the yield strength is not obvious, the specified plastic elongation strength Rp0.2 can be used instead of the upper yield strength.
ｂ:It is only applicable to steel plates of quality grade D.
ｃ:Applicable only to structural steel and bars.