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23/06 16:14
< Electro Galvanized Steel Sheet & Coil, size: 1.0*1250*C, grade: SECCN5(ASTM A879/A879M-22), brand: CHANGFA. Shanghai - Caoan reduction by --36.06 tons
23/06 16:14
< Galvanized Steel Sheet & Coil, size: 0.8*1250*C, grade: DC51D+Z(ASTM A653M CS), brand: BAOSTEEL. Shanghai - Caoan reduction by --33.91 tons
23/06 16:10
< Square & Rectangular Tubes, size: 50*100*3.75, grade: Q235(ASTM A36 Gr.D), brand: JUNCHENG. Tianjin - Gangrui reduction by --31.52 tons
23/06 16:09
< Seamless Steel Pipe, size: Φ25*3, grade: 20#(ASTM 1020), brand: HUITONG. Liaocheng - Pipe City reduction by --17.73 tons
23/06 16:09
< Seamless Steel Pipe, size: Φ48*3, grade: 20#(ASTM 1020), brand: HUITONG. Liaocheng - Pipe City reduction by --20.88 tons
23/06 16:09
< Seamless Steel Pipe, size: Φ140*20, grade: 20#(ASTM 1020), brand: HUITONG. Qingdao - Chengyang increased by 44.86 tons

Answers

  • What are the differences between transporting corrugated culverts as a whole pipe and transporting them in assembled units?

    Shorter corrugated culverts can be pre-assembled in the factory and then transported as a whole to the construction site for direct hoisting and installation. Longer culverts are transported in sections, transported to the site first, and then assembled on-site. Large-diameter culverts (diameter ≥ 3.0m) are typically transported in sections using sheet-like arc-shaped corrugated plates and assembled on-site with bolts.

    Whole pipe transportation: More suitable for projects with smaller diameters, good road conditions, and a need for rapid installation.
    Assembled unit transportation: Ideal for large-diameter culverts or projects located in remote mountainous areas or other areas with inconvenient transportation.


  • What are the technical performance and advantages of welded steel mesh?

    Ensuring project quality: The welded wire mesh is manufactured in the factory under strict quality control by a fully automated and intelligent production line. The grid size, steel bar specifications, and quality are all strictly controlled. This avoids situations where manual netting is missed, not securely tied, tied incorrectly, or where shoddy workmanship occurs. Its mesh has high rigidity, good elasticity, uniform and accurate spacing, and high weld strength. Therefore, it greatly improves the quality of the project.

    Improved seismic and crack resistance: The longitudinal and transverse bars of the welded wire mesh form a mesh structure, which has good bonding and anchorage with concrete. The load it bears can be evenly distributed, significantly improving the seismic and crack resistance of reinforced concrete structures. According to actual tests, the use of welded steel mesh in road paving can reduce cracking by more than 75% compared to manually tied mesh.

    Saving on steel reinforcement: The design strength value of a large number of coiled steel bars is 210 N/mm2, while the design strength value of welded steel mesh is 360 N/mm2. Based on the principle of equivalent strength substitution and considering other factors, using welded steel mesh can save more than 30% of the steel reinforcement usage. Furthermore, the steel mesh does not require further processing after it is transported to the construction site, so there is no loss.

    Speed up construction: Using steel mesh can make the project faster. Simply lay the welded wire mesh according to the requirements, and then pour the concrete. This eliminates the need for on-site cutting, placement, and tying of the steel bars. It can save 50%-70% or more of the working time, greatly speed up the construction progress, and shorten the construction cycle.


  • Differences in Production Processes between Cold Rolling and Hot Rolling?

    The production process of hot-rolled coils involves heating continuously cast slabs or rough-rolled slabs in a furnace to approximately 1250°C, bringing them to a red-hot, plastic state. They are then rolled under high pressure in multiple passes on roughing and finishing mills, ultimately coiled into coils.
    Its core characteristics are:
    1. High production efficiency and relatively low cost.
    2. Typically thicker products, commonly ranging from 3.0mm to over 20mm; thicker products require production as medium-thick plates.
    3. Due to the high-temperature rolling, a dark blue oxide scale (iron oxide scale) forms on the surface, resulting in a rough surface (rough texture). Dimensional accuracy and shape control are relatively poor, with thickness tolerances typically within ±10 microns.
    4. Mechanical properties include lower strength but good plasticity and ductility; the internal structure is equiaxed crystals.

    Cold-rolled coils, on the other hand, use hot-rolled pickled coils as raw material. After the oxide scale is removed in the pickling line, the hot-rolled coils are rolled at room temperature.
    Its core characteristics are:
    1. Extremely high product precision. Wide thickness range, from 0.3 mm to 3.0 mm or even thinner, with thickness tolerance controllable within ±1 micrometers, and a straight sheet shape.
    2. Excellent surface quality. Various exquisite surfaces can be obtained through subsequent processing, such as 2B (bright surface after cold rolling followed by heat treatment, pickling, or similar treatment), BA (bright annealed mirror finish), No.3/4 (ground surface), etc.
    3. Changes in mechanical properties. Cold work hardening significantly improves the material's strength, hardness, and fatigue resistance, but reduces plasticity. To restore plasticity, eliminate internal stress, and obtain the required mechanical properties, annealing treatment must be performed after cold rolling, followed by temper rolling (finishing) in the final stage.


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