The strength and toughness of heavy universal wheel -
Universal wheel, adjust the foot manufacturer before forging process on universal wheel material, usually adopts high heating and heat preservation temperature, so that produced in the process of molten steel in continuous casting of Nb carbide and carbon nitrides fully solid solution. For 0. 5% and 0 C. 06% Nb forged steel, Nb compounds under the conventional heating temperature of 1250 ℃ not completely solid solution. When the lower carbon content in steel, is under the same temperature the higher the content of solid solution of Nb. Solubility of micro alloying elements in steel, not only because of the influence of carbon content, but also affected by nitrogen, but in the universal wheel has a little influence on the solubility of micro alloying elements. In addition, forged steel, the equilibrium condition, the universal wheel almost all of the precipitation occurred in austenitic temperature range, and low-carbon HSLA steel ( High strength low alloy steel) Precipitation is large in under 900 ℃ temperature regions of ferrite, ferrite precipitates in size small, usually less than 10 nm for the use of the precipitation strengthening effect is good to improve the strength of the steel and formed in austenite precipitates was a relatively bulky size ( 20 - 50 nm it is good to control grain size universal wheel is the role of micro alloying elements in fine grains, traditionally. In order to improve the strength and toughness of steel, at the same time, relying on the analysis of micro alloying elements in further improving strength. The function of micro alloying elements in universal wheel is fine grains, in order to improve the strength and toughness of steel, at the same time rely on the analysis of micro alloying elements came out to further improve the strength. Commonly used micro alloying elements in steel TiNbV and the role of Al steel typically by precipitation strengthening to improve the strength of the universal wheel, solid solution strengthening effect of contribution to the strength of the steel is much lower, so these elements in the process of industrial production of austenitizing solid solubility should give enough consideration. Relative to the low carbon content of the flat material, high carbon steel is often found in the content of nitrogen, this will inevitably in the universal wheel form a large size because TiN TiN solubility product is small, the large size of TiN precipitates and steel produced in the process of solidification of a deposition on fatigue properties of materials and toughness is very bad, so want to limit the limit content of micro alloying elements. To contain CrMo steel, when the Nb content is 0. The carbon content of 09% more than 0. 6%, even under the condition of equilibrium there could still be a deposition.