Grain Boundary Steel Hot Working Process In The Copper Phase Formation And Controlling Research

This paper addresses the main source of residual copper in steel and what copper can effects the property of steel. The paper also elaborated the segregation of copper in the steel and residual copper heat brittle mechanism、influencing factors and suppression measurements. Understand and master the use of thermodynamic software Fact Sage, draw the Fe-Cu copper binary phase diagrams, analysis of iron, copper in oxidation under the condition of chemical reaction, calculating the thermodynamic parameters of reaction, judging it direction; Draw the Ni- Fe- Cu isothermal section ternary diagram(temperature from 1050 ℃, 1100 ℃ and 1100 ℃, 1200 ℃, 1250 ℃). Analysis on products of the percentage of nickel, iron, copper, judgment, nickel, copper, iron, under the condition of the oxidation reaction, calculate the Gibbs free energy, and energy spectrum determination results validation. The results showed that the trace nickel elements can have osmotic role in inhibition of Cu to the substrate.Experiment selected pure iron as melting master batch, the use of vacuum induction furnace for smelting, after pouring into 5 kg ingot casting, and cut out 10 ㎜×10 ㎜×10 ㎜ block sample. Samples from 1050 ℃, 1100 ℃, 1150 ℃, 1200 ℃, 1250 ℃ temperature gradient section surface oxidation, oxidation time for 3/4 h, 2 h. Using OM(optical microscope) and SEM(scanning electron microscope), EDS methods such as qualitative and quantitative analysis of surface oxidation were investigated.The results show that additions of nickel change the structure of copper rich phase in the oxide layer, promote the nickel copper rich phase retained in the oxide layer with granular, inhibit the penetration of Cu into the matrix, and improve thermal roblem caused by the residual copper.Adding nickel element and improving the heating process can improve or reduce the harm of copper steel hot works. Heating process including reducing furnace hearth oxygen, increase the rate of temperature, high temperature constant temperature keeping time and so on.