1. Scope
This code prescribes the technical conditions of carbon structure steel, including denotation, size, shape, weight and allowable deviation, specifications, testing methods, testing rules, packaging, marks and quality certificates.
The standard is applicable to general structural steel and hot-rolled steel plates, steel strip, formed steel and bar steel for works. The product can be used for weld, binding and bolting member. They are generally used under the supply state.
The chemical compositions stated in this code are applicable to the steel ingot, continuous casting billet, steel billet and its products.
2. Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this national standard. For dated reference, subsequent amendments to, or revisions of, any of these publications do not apply; but the parties to agreements based on this standard are encouraged to investigate the possibility of applying the latest editions of the standards indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 222-2006 Permissible variation of chemical composition for steel
GB 223.3 Method of chemical analysis on steel and alloy / the diantipyryl methane phosphomolybdate gravimetric method for the determination of phosphorus content
GB/T 223.10 Method of chemical analysis on steel and alloy / the cupferron separation-chrome azurol S photometric method for the determination of aluminium content
GB/T 223.11 Method of chemical analysis on steel and alloy /the ammonium persulfate oxidation volumetric method for the determination of chromium content
GB/T 223.18 Method of chemical analysis on steel and alloy /the sodium thiosulfate separation iodimetric method for the determination of cupper content
GB/T 223.19 Method of chemical analysis on steel and alloy / the neocuproine-chloroform extraction photometric method for the determination of copper content
GB/T 223.24 Method of chemical analysis on steel and alloy / the dimethylglyoxime spectrophotometric method for the determination of nickel content
GB/T 223.32 Method of chemical analysis on steel and alloy /the hypophosphite reduction-iodimetric method for the determination of arsenic content
GB/T 223.37 Method of chemical analysis on steel and alloy / the indophenol blue photometric method for the determination of nitrogen content after distillation
GB/T 223.58 Method of chemical analysis on steel and alloy / the extraction-absorption catalytic polarographic method for the determination of manganese content
GB/T 223.59 Method of chemical analysis on steel and alloy /the sodium arsenite-sodium nitrite titrimetric method for the determination of phosphorus content
GB/T 223.60 Method of chemical analysis on steel and alloy /the perchloric acid dehydration for the determination of silicon content
GB/T 223.63 Method of chemical analysis on steel and alloy / the sodium (potassium) periodate photometric method for the determination of manganese content
GB/T 223.64 Method of chemical analysis on steel and alloy /the flame atomic absorption spectrometric method for the determination of manganese content
GB/T 223.68 Method of chemical analysis on steel and alloy /the combustion potassium iodate volumetric method for the determination of sulfur content
GB/T 223.71 Method of chemical analysis on steel and alloy /the gravimetric method after combustion in the pipe furnace for the determination of carbon content
GB/T 223.72 Method of chemical analysis on steel and alloy /the alumina chromatographic separation-barium sulfate gravimetric method for the determination of sulphur content
GB/T 228 Metallic materials/tensile testing method in room temperature (GB/T228-2002, eqv ISO 6892:1998)
3. Denotation and symbol of number, code name
3.1 Denotation of number
The steel number is composed of the following parts in order, like letter representing yielding point, yielding point value, quality grade symbol, deoxidation method symbol, etc.
For example: Q235-A•F
3.2 Symbol
Q- first letter of Chinese Pinyin "屈(qu)" in steel yielding point.
A, B, C and D are quality class respectively.
F-first letter of Chinese Pinyin "沸(fei)" in rimming steel.
Z-first letter of Chinese Pinyin "镇(zhen)" in killed steel.
TZ-first letter of Chinese Pinyin "特镇(te zhen)" in special killed steel.
"Z" and "TZ" symbols are omitted in number composing denotation.
