Studies On Preparation And Performance Of A New Semi-synthetic Cutting Fluid

Metal cutting fluids were necessary in metal processing.In recent years,especially water-based cutting fluids were widely used in metal processing.As for the water-based cutting fluids,the semi-synthetic cutting fluid has excellent lubricity of the emulsified cutting fluid,great cooling performance and stability of the synthetic cutting fluid,so it has a good application prospect in metal processing,which have been become a hotspot in the field of cutting fluid.In this study,a new type of semi-synthetic cutting fluid with excellent rust,cooling,lubrication and cleaning characteristics were prepared to satisfy the demands of metal processing.In this thesis,two types of additives suitable for semi-synthetic cutting fluids were prepared,and a micro-emulsified system with good compatibility was formed by optimizing the ratio of emulsifier.On the basis of the previous researching works in our group,a new type of modified functional additive was added in the cutting fluid,meanwhile,a new semi-synthetic cutting fluid was synthesized.And the research were carried out in the following aspects:Firstly,the research were focused on improving the anti-rust performance of semi-synthetic cutting fluid,and to explore the anti-rust mechanism of its additives;Secondly,it is to study the stability of emulsification for semi-synthetic cutting fluid,and explored the regular of water-oil equilibrium to guide the selection and using of emulsifiers to improve the stability of emulsification for semi-synthetic cutting fluids.The main achievements of this research were shown as following:(1)Using dodecenylsuccinic acid(T746)and sebacic acid as main raw materials,two types of water-soluble anti-rust additives,dodecenylsuccinic acid diethanolamide(T746-X)and sebacic acid triethanol were successfully synthesized.The structure of ammonium salts were identified by Fourier transform infrared spectrometer;and its anti-rust ability and mechanism of semi-synthetic cutting fluid were investigated by wet heat method,electrochemical polarization curve and alternating current impedance spectroscopy(EIS).The results show that T746-X anti-rust agent and ammonium sebacate anti-rust agent have good anti-rust characteristics in semi-synthetic cutting fluid.And T746-X anti-rust agent passes nitrogen and carbonyl in the molecule.The lone pair of electron atoms and the iron atoms on the metal surface act to prevent the molecules such as oxygen and water from coming into contact with the metal surface to prevent rust.The ammonium sebacate type rust preventive agent forms an adsorption type passivation film by forming a multi-molecular layer adsorption on the metal surface,thereby preventing depolarization of oxygen at the cathode,thereby forming a barrier to diffusion of oxygen and preventing rust.(2)On the basis of the method bell-shaped curve,the effects of composite emulsifiers with different HLB values on the water-oil balance of semi-synthetic cutting fluids were investigated.By changing the proportion of oil agent,the state change and equilibrium law of the emulsion system were studied.The results show that under different oil ratios,the water-oil system exhibits a bell-shaped curve under the emulsification of a composite emulsifier in a certain HLB range,and there is a certain optimal HLB composite emulsifier for the water-oil system.The best emulsion stability.The total oil content can change the state of the emulsion under the low HLB emulsifier system,but the state of the emulsion could not change under the high HLB emulsification system.(3)Combine GB/T 6144-2010 cutting fluid national standard and JB/T 7453-2013 semi-synthetic cutting fluid industry standard to test the performance of new semi-synthetic cutting fluid.The results show that the performance of the new semi-synthetic cutting fluids meet the relevant standards of the products,which lays a foundation for the industrial application of the cutting fluid.