Chemical element composition of Chinese grade hot-rolled Q355NC low-alloy high-strength structural steel
Q355NC Approximate Grade Lookup Table

Table 1  Chemical Composition

Grade Chemical Composition（Quality Fraction） / %
Steel Grade Quality Grade C Si Mn Pᵃ Sᵃ Nb V Tiᶜ Cr Ni Cu Mo N Alsᵈ≥
≤ ≤ ≤
Q355N C 0.2 0.5 0.9~1.65 0.03 0.03 0.005~0.05 0.01~0.12 0.006~0.05 0.3 0.5 0.4 0.1 0.015 0.015
The steel should contain at least one of the grain-refining elements such as aluminum, niobium, vanadium, and titanium. When added alone or in combination, the content of at least one alloying element should not be less than the lower limit specified in the table.
a.For structural steel and bar stock, the upper limit for phosphorus and sulfur content can be increased by 0.005%.
b.V+Nb+Ti≤0.22%,Mo+Cr≤0.30%。
c.Up to 0.20%.
d.All-aluminum (Alt) can be used as a substitute, in which case the minimum content of all-aluminum is 0.020%. When grain-refining elements such as niobium, vanadium, and titanium are added to the steel and their content is not less than the lower limit specified in the table, there is no limit to the lower limit of aluminum content.

Table 2  Tensile properties

Grade Upper yield strength ReHᵃ/MPA
≥		 Tensile strength Rｍ/MPA Elongation after fracture A/％
≥		 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 ≤100 ＞100~200 ＞200~250 ≤16 ＞16~40 ＞40~63 ＞63~80 ＞80~200 ＞200~250 Vertical Horizontal
Q355N C 355 345 335 325 315 295 285 275 470~630 450~600 450~600 22 22 22 21 21 21 34 27
Note: Normalized condition includes normalized and tempered condition. a. When yield strength is not obvious, the specified plastic elongation strength Rp0.2 can be used instead of the upper yield strength ReH.