Development Of Medium-low Temperature Weak Alkali Phosphating-free Degreasing Powder Applied To The Surface Of Steel Parts

With the continuous promotion of "Made in China 2025",the high-end iron and steel industry has higher and higher requirements for processing technology and cleaner production.In the metal surface treatment industry,the surface of steel parts to be processed needs absolute cleanliness.Generally,the phosphorus containing degreaser can meet the corresponding requirements,but the phosphorus containing waste water is difficult to be treated,which is easy to cause eutrophication and water pollution when discharged into the environment,and the degreasing effect of phosphorus free degreaser is difficult to compare with the former.In order to protect the environment,clean production.and control the flow of phosphorus into the environment from the source,a kind of phosphorus-free degreasing powder applied to the surface of iron and steel parts is developed in this paper,and compared with the phosphorus-free degreasing powder and phosphorus-containing degreasing powder currently sold in the market,so as to ensure that its degreasing effect,energy consumption control and other aspects can achieve the effect of phosphorus containing oil removal powder or even better than the latter.In this paper,17 kinds of surfactants were tested for various performance indicators,and 3 kinds of surfactants OXO1306,JFC-2G and LAS-90 were screened out.The single-factor optimization experiment and orthogonal experiment determined the most of the 3 surfactants.The best working concentrations are 2 g/L,4 g/L and 6 g/L,respectively.The Zeta potential is measured to verify that these three surfactants have a good synergistic effect.Various performance indicators were measured for 14 kinds of non-phosphorus builders,three kinds of non-phosphorus builders ISS,NaGL and MGDA were screened out,and the three kinds of non-phosphorus builders were determined by single factor optimization experiment and orthogonal experiment.The optimal working concentrations are 5 g/L,3 g/L and 6.5 g/L,respectively.The determination of the Zeta potential verifies that the phosphorus-free builder formula can further improve the synergistic effect of each substance.The basic substance of the degreasing powder is Na2CO3,no strong alkali is needed,and the required additive is Na2SO4 to prevent the degreasing powder from agglomerating.Through the single factor optimization experiment,the best degreasing process parameters were determined(degreasing temperature:46?50?,degreasing time:8 min immersion degreasing+1 min still water rinse).The degreasing powder is used to degrease the steel parts,and the physical and chemical properties,rinsing performance and process energy consumption of the degreasing powder are tested.The degreased steel sheet is nickel plated,and the SEM and gloss test are performed.The results show that the CODCr of this degreasing powder is 8205.2 mg/L,and it does not contain phosphorus compounds.Unlike most of the currently commercially available compositions,no NaOH is required,which ensures that no alkali mist is generated during use.The ratio concentration of the oil solution is low(5.3%),that is,the addition cost is low,the degreasing temperature meets the low and medium temperature requirements,and the required degreasing time is shorter,that is,the degreasing speed is faster,these characteristics can reduce the production process.The cost of adding materials arid energy consumption,the use of this degreasing powder and its process meet the requirements of cleaner production.It has excellent performance,and the degreasing rate can reach 99.92%,which can play a strong role in non emulsion stripping of oil stains.Therefore,the quantity of steel parts that can be cleaned per unit volume of degreasing solution is large,so as to ensure a long service life of degreasing powder and reduce the water consumption and use cost of degreasing.After proper processing,the iron and steel parts cleaned by the degreasing powder can obtain a compact,flat and well-distributed nickel coating with high glossiness(3245 Gu),that is to say,the cleaned iron and steel parts have good surface properties.