Novel Polyether Quenching Medium Development And Optimization

Aqueous polymer quenching medium combines the advantage of the pro-environment, adjusted cold speed, good thermal stability and other ones, which is applied in many purposes. It has gradually replaced the traditional quenching medium, in Europe US and other developed countries, and become a research hotspot in the field of heat treatment of steel. But in domestic aqueous polymer quenching medium research is still in its beginning stage. The main problems are that the influence factors of aqueous polymer quenching medium and the management of knowledge need to be improved. Also the relationship between hardening medium composition and cooling characteristics should be further studied. Therefore, the development of a kind new aqueous polymer quenching medium with independent intellectual property rights is important for the application and theory.Based on an analysis of the previous literatures and experiments about the effect of main components of quenching medium on cooling characteristics, this paper presents the component radio of a new polyether water-based quenching medium. Tests of the physicochemical properties of the new polyether water-based quenching medium are performed through the density, viscosity, PH test. The cooling curve of polyether water-based quenching medium is conducted by using the cooling curve tester of innovation. Cooling curve method and cooling hardening capacity method are used to further evaluate the cooling characteristics of polyether water-based quenching medium. A serial of experiments are conducted focusing on the analysis of microstructure and impact toughness test of the samples after quenching, to study the actual quenching effect. According to the physicochemical properties, cooling characteristics and process of the polyether water-based quenching medium, the quenching medium compositions are further optimized. Through the comprehensive analysis the quenching mechanism of quenching medium, the following valuable conclusions are obtained:1) The polyether water-based quenching medium has the environmental protection because there is no toxic substance released in the process of quench. This kind of quenching medium has the property of inverse solubility to protect hardening work piece from deforming in marten site transformation area. And has the low property of the corrosion to extend the working time of quenching tank.2) The novel poly ether water-based quenching medium’s cooling capacity is between the oil’s and the water’s which can be adjusted by the medium concentration. The high concentration quenching medium is a potential substitution of mineral oil because of their similar cooling capacity. The developed polyether water-based quenching medium has a strong ability of the cooling hardening ability. The properties of ageing resistance and thermal stability are when the concentration of quenching medium is low, while they evidently become bad as the concentration increases. Therefore, the hardness uniformity of samples is inhomogeneous after the process of quenching.3) Novel polyether water-based quenching medium has a great ability of the harden ability. The organization of samples was composed of acicular marten site and a small amount of residual austenite after the process of the quench, however, as the concentration increased, the proeutectoid ferrite would appeared due to the deficiency of the cold speed in the fist cooling stage. The samples quenched by the quenching medium with low concentration had great structure stress and thermal stress to lead to the low impact toughness due to the cold speed too quickly.4) Aiming at the shortage of the novel polyether water-based quenching medium, the composition was further optimized according to the thought of composition optimized. The quenching medium optimized not only has the advantages of the high using concentration, the high cost, the aging of the high concentration medium and the inhomogeneous of the hardened layer.