What is the national standard for Q235 steel, and how can it be distinguished?
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Friend, what is the national standard for Q235 steel, and how many series are there? I would appreciate some guidance.
Chinese standards, 3 series I guess.
A previous name for it was: A3. Execution standard: The external standard is GB709, and the internal standard is GB3274-88
Q235 is a common carbon structural steel; only its mechanical properties are controlled, and the requirements regarding its composition are not strict, so it is generally used in less critical structural components. Q represents the yield strength of this material, and the 235 that follows indicates the yield value of this material, which is around 235 MPa. Q235A，Q235B，Q235C，Q235D。 This is a distinction based on grade, referring to the differences in impact temperature among their properties. They are respectively: Q235A grade, which does not undergo impact testing ； Grade Q235B: impact at 20 degrees Celsius ； Grade Q235C: impact at 0 degrees ； Grade Q235D corresponds to an impact test at -20 degrees Celsius. At different impact temperatures, the values of impact also vary.
Carbon structural steel GB/T700-1988: Grade Q235, Class A. Chemical composition (mass percentage): %C: 0.14–0.22; %Mn: 0.30–0.65; %Si②≤: 0.30; %S≤: 0.050; %P≤: 0.045. Deoxidation methods: F, b, Z. Grade Q235, Class B: Chemical composition (mass percentage): %C: 0.12–0.20; %Mn: 0.30–0.70; %Si②≤: 0.30; %S≤: 0.045; %P≤: 0.045. Deoxidation methods: F, b, Z. Grade Q235, Class C: Chemical composition (mass percentage): %C: ≤0.18; %Mn: 0.35–0.80; %Si②≤: 0.30; %S≤: 0.040; %P≤: 0.040. Deoxidation method: Z. Grade Q235, Class D: Chemical composition (mass percentage): %C: ≤0.17; %Mn: 0.35–0.80; %Si②≤: 0.30; %S≤: 0.035; %P≤: 0.035. Deoxidation method: TZ. Note: 1. The residual contents of Cr, Ni, and Cu in the steel should each be no more than ω = 0.30%; if the supplier can guarantee this, analysis is not necessary. 2. The nitrogen content in oxygen converter steel shall not exceed ω=0.008%. 3. F denotes boiling steel, b denotes semi-killed steel, Z denotes killed steel, and TZ denotes specially killed steel. ①For Q235A and grade B boiling steel, the upper limit for Mn content is ω=0.60%. ②The Si content in boiling steel shall not exceed ω=0.07%, the Si content in semi-killed steel shall not exceed 0.17%, and the lower limit for the Si content in killed steel is ω=0.12%. This post was last edited by wefxy on 2009-3-30 15:33]
Damn, it’s China’s ABC series
The standard has now been changed to the new standard GB700-2006, which can be downloaded for viewing.
The replies on the fourth floor are great! The replies on the third floor are also great! Support them! Q is the yield point, and 235 refers to a yield strength of around 235 MPa. The grades are classified as: A ； B ； C ； Level D 4: The casting processes are divided into ； 3# converter boiling steel F, 3# converter semi-killed steel b, 3# converter killed steel Z, and special killed steel TZ; their carbon content is at ； Between 25% and 45%; its contents of sulfur, phosphonium, manganese, etc. are as mentioned by the poster on the fourth floor! It’s basically the same as the previous A3 material!