Hot-rolled steel surface roughness

Apr 22 09:36 2015 Henary Lee Print This Article

Liberation truck frame assembly of stringers and stiffeners, beams and plate and the material portion of the stent are used 355L hot-rolled steel, depending on the structural strength requirements, the use of hot-rolled steel 355L thickness of about 3 ~ 8mm. 

Liberation truck frame assembly of stringers and stiffeners,Guest Posting beams and plate and the material portion of the stent are used 355L hot-rolled steel, depending on the structural strength requirements, the use of hot-rolled steel 355L thickness of about 3 ~ 8mm.

Hot-rolled seamless steel pipe in the rolling process, the surface due to the formation of high temperature black oxide by ferrous oxide, iron oxide and iron oxide composition, therefore, often referred to as black steel hot-rolled steel. Hot-rolled steel surface oxide film is very thin, and the combination of the dense body, not falling. Commonly used methods of chemical rust rust and mechanical descaling method, large pieces of rust in the past to use more chemical descaling method - pickling rust, due to greater environmental pollution, acid rust has gradually been eliminated, and replaced by a mechanical descaling method, use more mechanical descaling shot blasting. Shot blasting high-speed rotation of the impeller, the steel shot thrown steel surface, so as to achieve the purpose of rust, is a more advanced method of mechanical treatment of the steel to rust, with high efficiency, low cost, degree of automation high, can realize the pipeline operation and environmental pollution characteristics, are widely used in steel and automobile manufacturing. Hot rolled steel plate after shot blasting, surface roughness has a significant influence on the cathodic electrodeposition coating corrosion resistance. Found that with increasing roughness of the surface of the hot-rolled steel sheet, the corrosion resistance of the coating can be reduced. When the hot-rolled steel sheet in the 3.4 ~ 4.4μm Ra or less roughness, coating corrosion resistance and cold-rolled steel corrosion coatings fairly; when hot-rolled steel sheet roughness Ra of 7.0 ~ 9.0μm, the coating corrosion layer coating with the hot rolled steel sheet without shot blasting treatment considerably the corrosion resistance; when hot rolled steel sheet roughness Ra of 9.0 to when 12.0μm, the coating corrosion resistance severely degraded. Blasting is used to adjust the spot diameter steel shot (from the original Φ1.0 ~ 1.2mm down to Φ0.5 ~ 0.8mm), ensures that the workpiece by cathodic electrodeposition coating quality reach CA / C202 A standard. For lower coating standards require special piece, you can decide whether to adopt the blasting process according to the oxidation state of the surface of the skin. If the oxide surface has not been damaged, you can cancel the blasting process; the liberation of the truck frame assembly currently stringers and stiffeners, beams and webs, some stents were destroyed oxide circumstances exist, in painting must be used before the blasting process.

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Henary Lee
Henary Lee

Hot-rolled steel surface roughness

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