Answers

• 
  What are the specifications of construction scaffolding steel pipes?

  Generally speaking, the common diameter specifications are 3cm, 2.75cm, 3.25cm, and 2cm. The length specifications are generally between 1-6.5m. There are many specifications for wall thickness, and the common ones are 2.5mm, 2.75mm, 3mm, 3.25mm, and 3.5mm. The selection of these specifications is mainly determined based on the specific project requirements and the stress conditions of the scaffolding.

  
  
• 
  What are the materials of the prepainted steel coil?

  The materials of prepainted steel coils mainly include substrate materials and coating materials.
  
  Substrate materials: The substrate materials of prepainted steel coils usually include cold-rolled steel sheets, hot-rolled steel sheets, galvanized steel sheets, and galvanized steel sheets. Among them, galvanized steel sheets and galvanized steel sheets are commonly used substrates for prepainted steel coils because of their good corrosion resistance.
  
  Coating materials: Coating materials are the key factors of color-coated coils, which mainly determine their appearance, weather resistance, and corrosion resistance. Common coating materials are:
  (1) Polyester (PE): Polyester coating has good adhesion and flexibility, and is suitable for construction, home appliances, and other fields.
  (2) Silicon-modified polyester (SMP): Silicon-modified polyester coating further improves weather resistance and corrosion resistance based on maintaining the performance of the polyester coating, and is suitable for outdoor construction, home appliances, transportation, and other fields.
  (3) High weatherability polyester (HDP): High weatherability polyester coating has excellent performance in weather resistance and corrosion resistance, and is suitable for high-demand outdoor construction and engineering fields.
  (4) Polyvinylidene fluoride (PVDF): Polyvinylidene fluoride coating has excellent weather resistance, corrosion resistance, and pollution resistance, and is widely used in high-end buildings, airports, subways, and other fields.
  (5) Silicone (Si-PU): Silicone coating combines the advantages of silicone and polyurethane, has high weather resistance, corrosion resistance, and self-cleaning performance, and is suitable for high-end construction and engineering fields.
  
  In the production process of prepainted steel coil, different substrate materials and coating materials can be selected according to the use requirements and environmental conditions. At the same time, the performance of prepainted steel coils can be further improved by double-sided coating, double-layer coating, and other methods.

  
  
• 
  What is the difference between Q345 and Q235?

  1. Different lower limits of yield strength: Yield strength refers to the critical stress value at which a material begins to undergo plastic deformation when subjected to tensile force. The lower limit of yield strength of Q235 is 235MPa, while the lower limit of yield strength of Q345 is 345MPa.
  2. Different steel categories: Q235 belongs to ordinary carbon steel, which refers to steel with a low carbon content; while Q345 belongs to low alloy steel, which refers to steel with a small amount of alloy elements added to ordinary carbon steel to improve its performance.
  3. Different composition: Q235 is made of carbon structural steel, which refers to steel composed of iron and carbon elements without other alloy elements; while Q345 is made of low alloy structural steel, which refers to carbon structural steel with a small amount of alloy elements added.