What are the necessary knowledge of galvanized sheet trade?

1. the main use

Hot galvanized sheet is mainly used in automobile, home appliances, construction, machinery, electronics, light industry and other industries.

2. steel galvanized classification

Steel factory galvanized products have two types of galvanizing, hot-dip galvanizing methods, and these two categories are subdivided, electric galvanizing from the thickness of the zinc layer is divided into single-sided, double-sided and differential thickness coating three categories, and hot-dip galvanizing is not single-sided and differential thickness coating, but hot-dip galvanizing is divided into galvanized and galvanized iron alloy, electroplating is not zinc iron alloy. The plating on the type of coating is extended to electrogalvanized, electrogalvanized nickel, electroplated tin, electroplated chromium, and the extension of hot galvanizing is more, including hot galvanizing, zinc iron, aluminum zinc, zinc aluminum, and zinc aluminum magnesium.

3. Annealing method

The annealing methods of conventional cold-rolled coated products are continuous annealing and mask annealing.

4. commonly used steel

Product categories: General coil (CQ), deep drawing hot galvanized sheet (DQ), super deep drawing hot galvanized sheet (DDQ-EDDQ/SEDDQ), structural galvanized sheet (HSLA), bake hardening hot galvanized sheet (BH), duplex steel (DP), TRIP steel (Phase change induced plastic steel), composite phase steel (CP), etc.

5. Defects of hot dip galvanizing

Zinc layer peeling, scratches, passivation spots, zinc particles, thick edges, air knife stripes, air knife scratches, exposed steel, inclusions, mechanical damage, poor steel base performance, wave edges, bending, improper size, imprinting, improper zinc layer thickness, roll printing, etc.

6. the main reason for zinc layer shedding

The main causes of zinc layer shedding are raw material production and processing mismatch. Raw materials due to surface oxidation, silicon compounds, NOF oxidation atmosphere and protective gas dew point is too high, air fuel ratio is unreasonable, hydrogen flow is low, furnace oxygen infiltration, strip steel into the pot temperature is low, NOF furnace temperature is low, oil evaporation is not enough, zinc pot aluminum content is low, unit speed is too fast, insufficient reduction, zinc liquid residence time is too short, coating thickness. Processing mismatches include bending radius inconsistency, mold wear, scratching, mold clearance is too large or too small, stamping lubricating oil is less, mold working time is too long without grinding maintenance.