How to distinguish between Q235B and Q235A steel coils (on-site)?
A: Check the quality certificate (impact test item); on-site differentiation is not possible, and mixing is strictly prohibited (A is not suitable for welded structures).
What are the mechanical property retesting requirements for Q235 steel coils (building codes)?
A: According to GB 50205 "Standard for Acceptance of Construction Quality of Steel Structures", yield strength, tensile strength, elongation, and cold bending are retested for each batch; carbon equivalent is also tested for welded structures.
At what extent should Q235 steel coils be corroded before they can be used in construction?
A: Corrosion depth > 10% of nominal thickness, large-area pitting corrosion, or dimensional deviations caused by corrosion are strictly prohibited for use in load-bearing structures; they can be downgraded for non-load-bearing enclosures.
What are the common processing techniques for Q235 steel coils in construction?
A: Leveling → Cutting (shearing/plasma/laser) → Cold bending → Punching → Welding → Painting. This process is low-difficulty and highly efficient.
What are the key points of the welding process for Q235 steel coils (construction)?
Answer: Use E43 series welding electrodes (such as E4303); Q235B and above can be welded in all positions; control the welding current, voltage, and speed to avoid overheating and cracking; clean the weld slag and inspect the weld (appearance/non-destructive) after welding.