Chemical element composition of Chinese grade hot-rolled Q390C low-alloy high-strength structural steel
Q390C 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 ≤
≤
Q390 C 0.2 0.55 1.7 0.03 0.03 0.05 0.13 0.05 0.3 0.5 0.4 0.1 0.15 -
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 to 0.2%
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
Q390 C 390 380 360 340 340 320 — — — 490~650 620 — — 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.