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  • 31/08/2023

    FEATURE|Correspondence between Chinese and other National Steel Grades

    The steel grade is a numbering system used to identify different types and properties of steel. Every country or region has its steel grade system, and these grades are usually composed of numbers, letters, and symbols, which could describe the composition, properties, uses, and other information of steel.

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  • 31/07/2023

    FEATURE|Where are the sources for CSMC steel price data?

    In international trade, the most significant issue is the price issue. As a professional platform company providing steel market information, CSMC is committed to creating a platform for customers that could provide independent, up-to-date, and accurate price information and ensure a safe and reliable transaction process. CSMC ensures that all sources of price data are independent and objective. We will conduct cross-validations of data from different sources, check manual reviews for errors, and strive for objective and accurate data.

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Short News
02/09 17:14
< On September 2, there was not much fluctuation in the price of welded steel pipe in Guangzhou. Q235 (ASTM A36 Gr.D) Zhenhong DN150 (6"*4.5mm) 533.40, down 2.85. (USD/ton)
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02/09 17:13
< On September 2, the price of I-beam in Dalian fell slightly. Q235B (ASTM A36) Baode 40# (400×142×10.5) mm 464.80, down 2.80. (USD/ton)
02/09 17:12
< On September 2, the price of cold-rolled steel plate in Foshan fell slightly. SPCC (ASTM A1008 CS) Liugang 2.0*1500*3000mm 557.20, down 2.80. (USD/ton)
02/09 17:10
< On September 2, the price of bridge steel plate in Anyang rose slightly. Q420qD (ASTM A709 Grade 50) Angang 10mm 728.00, up 7.00. (USD/ton)
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02/09 17:08
< On September 2, the price of galvalume steel sheet & coil in Shanghai remained stable. AZM150 (ASTM A792/A792M CS) Yehui 0.8*1100*C 728.00. (USD/ton)
02/09 17:07
< On September 2, the price of hot rolled patterned coil in Wuxi fell slightly. H-Q235B (ASTM A36) Shagang 9.5*1500*C 490.00, down 4.20. (USD/ton)
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Answers

  • What are Q235R and Q345R?

    Q245R and Q345R are two commonly used pressure vessel steel plate materials. The "R" in the designation stands for "vessel," and the number indicates the yield strength grade.

    Yield Strength:
    Q235R has a yield strength of approximately 235 MPa, while Q345R has a yield strength of up to 345 MPa. This means that under the same external force, Q345R is more resistant to deformation and offers greater structural safety.

    Chemical Composition:
    Q235R has a relatively high carbon content, while its manganese content is within a certain range. Q345R, on the other hand, has a lower carbon content and stricter control over impurities such as phosphorus and sulfur. This allows Q345R to maintain good strength while also exhibiting superior ductility, toughness, and weldability.

    Q235R typically has a temperature limit of around 400°C, making it suitable for low- to medium-temperature and pressure environments. Q345R, on the other hand, boasts increased strength and thermal stability due to the addition of trace alloying elements, allowing for safe long-term use below 450°C. Both steels are widely used in petrochemical, boiler, and storage tank equipment, and the selection process should consider both operating temperature and pressure requirements.


  • What is the difference between Q235B and Q235D?

    Both Q235D and Q235B are carbon structural steels. Ordinary carbon structural steel plate is a type of steel.
    The "Q" represents the yield strength of the material, and the "235" at the end refers to the yield value of the material, which is approximately 235 MPa.

    Chemical Composition
    Q235B: C ≤ 0.20; Mn ≤ 1.40; Si ≤ 0.35; S ≤ 0.045; P ≤ 0.045.
    Q235D: C ≤ 0.17; Mn ≤ 1.40; Si ≤ 0.35; S ≤ 0.035; P ≤ 0.035.

    Low-Temperature Impact Toughness
    Q235D: -20°C impact toughness test performed.
    Q235B: Room-Temperature (20°C) impact toughness test performed.

    Q235B is suitable for applications where performance requirements are guaranteed at room temperature (20°C), while Q235D requires performance to be maintained at -20°C.

    Strength and Plasticity:
    Both have similar yield strength (≥235 MPa) and tensile strength (375–500 MPa);
    However, due to its pure composition and rigorous manufacturing process, Q235D exhibits superior plasticity and low-temperature stability.


  • What are the various coating types for hot-dip galvanizing?

    Hot-dip pure zinc (Z)
    In the hot-dip pure zinc process, the zinc content in the molten pool must be no less than 99%. Pure zinc coatings can produce spangles of varying sizes. While these spangles affect the surface appearance, they do not affect corrosion resistance.

    Hot-dip galvanized aluminum (ZA)
    The molten metal in the molten pool contains approximately 5% aluminum (Al) and a small amount of rare earth elements, with the remainder being zinc. Zn-Al coatings have a brighter surface and offer greater corrosion resistance than pure zinc coatings, but are less commonly used in China.

    Hot-dip aluminum silicon (AS)
    The molten metal in the molten pool contains approximately 8% to 11% silicon (Si), with the remainder being aluminum. Al-Si coatings form a distinct aluminum-iron-silicon alloy layer on the steel surface. They offer excellent high-temperature resistance, making them suitable for high-temperature processing and operating environments. Hot-dip Al-Si coated steel sheets and strip are a type of "aluminum-coated sheet" referred to in the trade.

    Hot-dip galvanized magnesium (ZM) coatings, also known as zinc-aluminum-magnesium (ZAM), consist of a molten metal pool composed of aluminum and magnesium, typically 1.5-8% combined (at least 0.2% magnesium is required), with the remainder being zinc. This coating offers exceptionally good overall corrosion resistance, particularly for shear fracture protection.


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