Process for smelting steel for ultrafine silicon carbide sawing wire

A process for smelting steel for silicon cardide (SiC) sawing wires, comprising the following steps of:

• 1) melting a raw material into liquid molten steel under the protection of argon in a vacuum induction furnace, the raw material uses carbon-free pure iron and low-phosphorus pig iron having a carbon content of 3.5%-4.5% by mass and a phosphorus content of less than 0.06% by mass;
• then vacuumizing to perform vacuum smelting, the vacuum smelting is performed under a condition of less than 300 Pa to degas for 15-20 min, and performing deoxygenation with silicon iron with a silicon content of 75-85% by mass and an aluminum content of less than 0.05% by mass as a deoxidizer to adjust components of the molten steel, wherein aluminum-containing deoxidizer is not used in the deoxygenation;
• and after the adjustment of the components of the molten steel, casting circular ingots under vacuum condition, wherein each ingot has a mass of 1500-2500 kg, a diameter of 0.35-0.4 m and a length of 2-3 m;
• 2) cleaning the surface of the circular ingots to manufacture electrode bars for electroslag smelting;
• 3) remelting and smelting the electrode bars as raw materials in an electroslag furnace, wherein an electroslag protecting slag comprises the following in percentage by mass:
• CaF2:
• 45-55%, Al2O3:
• 15-25%, SiO2:20-25%, Na2O:
• 2-4%, and K2O:
• 1-2%;
• and
• smelting the electrode bar in the electroslag furnace into a cylindrical electroslag ingot having a diameter of 0.4-0.5 m, wherein the electroslag ingot has inclusions with a size of less than 13 μm;
• 4) forging the electroslag ingot into a forged billet for wire rolling, wherein the forged billet is a square billet having a cross section of square with a side length of 0.140-0.160 m, and the forged billet has a length of greater than 6 m;
• and
• 5) rolling the forged billet into a steel wire rod having a diameter of 4.5-5.5 mm by the wire rolling process, wherein the steel wire rod comprises the following chemical elements in percentage by weight:
• [C]:
• 0.92-1.1%, [Si]:
• 0.3-0.4%, [Mn]:
• 0.5-0.8%, [Al]:
• less than 0.0008%, [N]:
• less than 0.005%, [S]:
• less than 0.01%, [P]:
• less than 0.015%, and the balance of Fe and inevitable impurities.