In the steel industry, surface treatment has always been an unavoidable topic. Many customers are most concerned about not the material itself, but "to what extent the surface treatment is done", "whether it can be rustproof" and "whether it will change color after processing". Let's briefly talk about several common ways, which are often encountered in daily projects, hoping to give some reference to friends who have just come into contact with steel.
- pickling
Main function: to remove scale, welding slag and slight rust, and make the surface cleaner. Surface effect: matte, uniform color. Pickling is more like "washing the bottom" of the material. Many hot-rolled coils, steel pipes and flanges will be pickled after heat treatment, which is convenient for subsequent processing and surface inspection. Applicable scenarios: Cleaning the surface after heat treatment Follow-up welding/machining Industrial processed parts do not require bright surface. Small experience: pickling is not to make it beautiful, but to "return the surface to a clean state".
- polishing
Goal: Make the surface bright, smooth and beautiful. Type: common 2B, BA, #4 wiredrawing, 8K mirror. Whether the polishing is done well or not can be seen by the naked eye. Mirror stainless steel elevator board, kitchen equipment and decorative parts are all "heavy users" of polishing. Applicable industries: Food production equipment Medical instruments Hardware for furniture and decoration Elevator, cabinet, household appliance shell Reminder: The brighter the polishing, the more afraid of scratches, and the transportation and packaging must be careful.
- Galvanizing
Objective: To prevent corrosion and rust. Common methods: hot galvanizing/cold galvanizing. The galvanized zinc layer is thicker, which is more suitable for long-term outdoor; Cold galvanizing is thinner and looks better, but its corrosion resistance is not as long as hot galvanizing. Typical application: Outdoor steel structure Iron towers, railings, pipes Mechanical support, profile parts Note: After welding, galvanized parts need to be partially supplemented with zinc, otherwise the weld will rust first.
- sandblasting
Function: Polishing, removing rust, cleaning oxide scale, and improving the adhesion of subsequent coatings. The surface is even and slightly rough matte texture. Many paint spraying projects are sandblasting first and then painting. The corrosion resistance will be much better.
Application scenario
Ship structural member Mechanical frame Pretreatment of outdoor steel structure painting Bottom line: Want the paint to stick firmly? Sandblasting is more reliable than direct painting.
