| Colled-rold steel is applied to industrial production and all aspects of life,and it is the driving force for the development of science and technology.But cold-rolled steel is prone to rust in atmosphere.This corrosion phenomenon can bring out many negative impacts with different degrees on the industrial production and human's life.In 2008,the result of the investigation by China's ministry of industry and natural environment corrosion investigation teams showed that the direct economic loss was amount to 230 billion yuan,the indirect economic loss was 500 ~ 600 billion yuan caused by corrosion,which were equal to the 5?of our country's gross national product(GNP)at that time.So research on the way to prevent steel corrosion becomes very important.In this paper,the atmospheric corrosion law of cold-rolled steel and two temporary protection methods :VCI packaging materials and water-based rust inhibitor were studied.1)In this paper,the corrosion phenomena were studied according to atmospheric exposure test and indoor accelerated corrosion simulation test,draw a conclusion: the corrosion weight gain rate showed a trend of increasing first then decreasing to flatten out in the atmospheric corrosion test;the corrosion of clod-rold steel is most serious in simulated Marine industrial atmosphere;In the relative humidity test,the critical relative humidity of this cold-rold steel is determined of 75%.2)VCI is the focus of the antirust packing,so in order to meet the requirements of green packaging,VCI which is high efficiency,low toxicity and economic is to be researched and developed.In this section,through orthogonal test L16(45).? salt spray test on specimens and calculating the weightlessness rate and corrosion rate,some better formulas can be chose,at the same time,making range analysis on the result of the orthogonal test.The orthogonal optimal scheme can be concluded,and the optimal formula is: 5.0g/L of urotropin,7.0g/L of sodium benzoate,1.0g/L of BTA,25.0g/L of sodium silicate,4.0g/L of triethanolamine.Then it can treat the better formulas in corrosion resistance and the orthogonal optimal formula with electrochemical and damp heat test,the corrosion potential of the optimum formula range from-707.875 mV up to-434.206 mV,Through salt spray test,electrochemical test and hot and humid,an unity result on corrosion resistance was concluded,the order of the corrosion resistance is: the orthogonal optimal formula > 6# >16# > 14#.These showed that the gas phase anti-rust paper had a good anti-rust effect on colled-rold steel.3)At present,in order to overcome the shortage of water-based anti-rust agent,such as:poor antirust effect,containing toxic substances and so on.A water-soluble anti-rust inhibitor without nitrite was researched.By orthogonal experiment method,the optimal formula of water-soluble anti-rust inhibitor was determined.The optimal anti-rust inhibitor formula is: 250 g/L of sodium silicate,1.0g/L of triethanolamine,2.0g/L of boric acid,0.12g/L EDTA,0.8g/L sodium tungstate.This anti-rust water can completely covered the surface of the metal,also,there is no obvious color change before and after dipping anti-rust water on cold-rolled sheet.The stability of this anti-rust water could up to 82 days,the corrosion potential moved to-485.488 mV,the days of atmospheric corrosion experiments can reach to 36.This water-based anti-rust inhibitor had good corrosion resistance and low cost,so it has good prospects. |
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