1, what is the main use of hot galvanized sheet?
A: Hot galvanized sheet is mainly used in construction, household appliances, automobiles, machinery, electronics, light industry and other industries
2. What kinds of galvanizing methods are there in the world?
A: There are three kinds of galvanizing methods: electric galvanizing, hot galvanizing and coated galvanizing.
3. What two types of hot dip galvanizing can be divided into according to the different annealing methods?
A: It can be divided into two types: in-line annealing and off-line annealing, which are also called protective gas method and flux method.
4. What are the commonly used steel grades of hot galvanized sheet?
A: Product type: General coil (CQ), galvanized sheet for structure (HSLA), deep drawing hot Galvanized sheet (DDQ), baking hardening hot galvanized sheet (BH), dual phase steel (DP), TRIP steel (phase change induced plastic steel), etc.
5. What are the forms of galvanizing annealing furnace?
Answer: there are three kinds of vertical annealing furnace, horizontal annealing furnace and vertical horizontal annealing furnace.
6, usually there are several cooling modes of cooling tower?
A: There are two kinds: air-cooled and water-cooled.
7. What are the main defects of hot dip galvanizing?
Answer: Mainly: fall off, scratch, passivation spot, zinc grain, thick edge, air knife striation, air knife scratch, exposed steel, inclusion, mechanical damage, poor performance of steel base, wave edge, ladle curvature, size, imprint, zinc layer thickness, roll printing, etc.
8. Known: the specification of the production is 0.75×1050mm, and the coil weight is 5 tons. What is the length of the coil strip? (Specific gravity of galvanized sheet is 7.85g/cm3)
Answer: The coil strip length is 808.816m.
9. What are the main reasons for zinc layer shedding?
Answer: The main reasons for zinc layer shedding are: Surface oxidation, silicon compounds, cold binding emulsion is too dirty, NOF oxidation atmosphere and protective gas dew point is too high, air fuel ratio is unreasonable, hydrogen flow is low, the furnace oxygen infiltration, the temperature of the strip into the pot is low, RWP section furnace pressure is low and the door air absorption, NOF section furnace temperature is low, Oil evaporation is not enough, zinc pot aluminum content is low, the unit speed is too fast, insufficient reduction, zinc liquid residence time is too short, thick coating.
10. What are the causes of white rust and black spots?
Answer: black spot is white rust further oxidation formation. The main reasons for white rust are as follows:Poor passivation, passivation film thickness is not enough or uneven; The surface is not coated with oil or residual moisture on the surface of the strip; The surface of strip contains moisture when coiling; Passivation is not completely dried; Damp or rain during transportation or storage; Product storage time is too long; Galvanized sheet and other acid and alkali and other corrosive medium contact or stored together.
Post time: May-28-2022