The necessity of analysis and testing of silicon-phosphorus manganese - Master's thesis - Dissertation

Silicon is mainly present in solid solution in steel, mainly in the form of Fe2Si, FeSi or a more complex compound FeMnSi. The affinity of silicon and oxygen is second only to aluminum and titanium, but stronger than chromium, manganese and vanadium. Used as a reducing agent and a deoxidizer. Silicon can enhance the tensile strength, elasticity, acid resistance and heat resistance of steel, and increase the electrical resistivity of steel. Therefore, silicon in steel is generally not less than 0.1; as an alloying element, it is generally not less than 0.6%; acid-resistant heat-resistant steel And the silicon in the spring steel is higher, and the silicon content of the silicon steel can be as high as 4% or more; the phosphorus element is mainly in the solid solution state and the phosphide (Fe2P, Fe3P, etc.) in the steel, and is often in a separated state, and Fe3P is a A very hard substance, prone to cold and brittle phenomenon, thus affecting the forging of steel; phosphorus is one of the harmful elements in steel, the general content is below 0.06%, the quality steel is below 0.04 or 0.03, and the special case is also more than 0.1% ( Such as free-cutting structural steel); most of the phosphide in steel can be dissolved in acid, but it will escape with PH3 when dissolved with non-oxidizing acid, and H3PO4 and H3PO3 in oxidizing acid, so when analyzing phosphorus It is necessary to use an oxidizing acid to dissolve the sample, and then use a strong oxidizing agent to oxidize H3PO3 to make all the phosphorus to form H3PO4 to determine the phosphorus; the manganese element is mainly present in the MnS state in the steel, and the manganese is usually used as a desulfurizing agent in the process of smelting steel. Deoxidation and deliberate addition, manganese and sulfur can prevent Hot brittle, thereby improving the forgeability of the steel; content in the steel is generally from 0.3 to 0.8%, manganese content exceeds 0.8% is the steel, pig iron is generally in the range of 0.5 to 2%. High manganese steel can reach 13~15%, and manganese can be dissolved in dilute acid to form divalent manganese ions. When the manganese content is high, it is easy to produce brown turbidity in the case of low acidity solution, and the high content makes the oxidation of other elements in the solution difficult to complete, such as phosphorus in high manganese steel.
Testing equipment introduction
HXS-4AD metal multi-element analyzer is produced by Nanjing Huaxin Analytical Instrument Manufacturing Co., Ltd. It is the latest multi-element analyzer in China. It can detect ordinary carbon steel, high medium and low alloy steel, stainless steel, raw cast iron and nodular cast iron. Various materials such as silicon, manganese, phosphorus, copper, nickel, chromium, molybdenum, titanium, rare earth, magnesium, vanadium, aluminum, tungsten and rhenium are used in various materials such as alloy cast iron and ferromanganese. There are four large channels, brand computer control, full Chinese menu operation, desktop printer print results. It can meet the needs of metallurgy, machinery, casting and other industries in the multi-element analysis of materials in front of furnaces, finished products, incoming materials and other aspects.

Analytical method: photoelectric colorimetric analysis

Range: 0-1.999A absorbance value, 0-99.99% concentration value

(Examples of silicon, manganese, phosphorus, nickel, chromium, molybdenum, titanium, rare earth, magnesium in ferrous metals)

Mn: 0.010 to 18.00% P: 0.0005 to 2.000% Si: 0.010 to 6.000% ΣRE: 0.010 to 0.500%

Mg: 0.010 to 0.200% Cr: 0.01 to 28.000% Ni: 0.010 to 30.000% Mo: 0.010 to 7.000%

Ti: 0.010 to 5.000%