How to choose Q235 and Q345 spiral steel pipe

According to the design of the specific structure of the spiral steel pipe. If the structure is strength control, Q345 spiral steel pipe can be considered. If the structure is a stiffness control, Q235 spiral steel pipe may be considered. The price Q345 is slightly more expensive, but due to its high strength, it can save material. Specific selection can be comprehensively compared from the above points. Q235\Q345 is based on the yield strength of the steel, which is 235MPa and 345MPa, respectively, Q345 is slightly more expensive, but the price difference is not great.
Q235--Metal structural parts, carburized or cyanidized parts with low requirements for core strength, tie rods, connecting rods, hooks, couplers, bolts, nuts, sleeves, shafts and welded parts Q345 - Good comprehensive mechanical properties, low temperature It also has good performance in plasticity and weldability. It is used as structure, mechanical parts, building structure, general metal structure parts for low and medium pressure vessels, oil tanks, vehicles, cranes, mining machinery, power stations, bridges, etc. Normally used, it can be used in various structures below -40°C in cold areas.