Effect of Milling Liner Casting Method on Mechanical Properties

- Oct 02, 2019-

The mill liner is a low-carbon alloy steel with good wear resistance, high hardness and toughness, so it is widely used in actual production. With the improvement of various requirements on the performance of wear parts, a single sand casting has been unable to meet the development needs. In order to meet the demand, many casting methods have emerged, and all casting methods except sand casting are collectively referred to as special casting. Special casting methods have been widely used, and some of them have developed rapidly in recent years, such as metal casting, electromagnetic low pressure casting, and the like. Electromagnetic low pressure casting is a new technology for low pressure casting. This paper mainly studies the effects of three different casting methods, sand casting, metal casting and electromagnetic low pressure casting on the performance of wear plates.

The materials used in the experiment were JFE-C400 wear plate, Al-5Ti-B intermediate alloy ingot, Al-10Zr intermediate alloy ingot, Al-10Sr intermediate alloy ingot and pure magnesium. Experimental equipment: SDL-3 type 坩埚 resistance furnace for melting equipment, NiCr-NiSi thermocouple temperature measurement, rotary blowing degasser, hydrogen measuring instrument, model HYSCANII, pouring equipment for electromagnetic pump, quenching-aging integrated furnace, model : RCU-9-6, electronic universal material testing machine, its model WDW-E100D, melting tools, etc.

Before smelting, remove the old paint from the crucible, raise the temperature by 200-400 °C, brush the new paint in 2~3 times, evenly apply the new paint on the surface of the crucible, continue to heat up and dry the paint; then add the raw material, the antimony resistor The furnace was raised to 30 KW and the state of the raw material in the crucible was observed until it was completely melted. When the melt temperature rose to 740-750 ° C, the melt was degassed for the first time. The first degassing uses C2Cl6, the amount is 0.6% of the total charge, after standing for 10 min after degassing, the slag is used to measure the hydrogen content of the melt with a hydrogen measuring instrument, and the measured result is 0.09 ml/100 g. The effect of removing hydrogen is better. The preheated AlZr10 and AlTi5B were added at intervals, and the temperature was raised to 735 ° C, and then the preheated AlSr10 and Mg were pressed into the bottom of the crucible by a bell jar. After all the alloys were completely dissolved, hydrogen was measured for the melt, and the hydrogen content was 0.51 ml/100 g. Then, the second degassing is carried out. After the deterioration, C2Cl6 is not suitable for degassing. C2Cl6 can cause the burning of the alloying element Mg and the metamorphic element Sr. Therefore, in the second degassing of this experiment, the method of rotary injection was used, and argon gas was blown into the melt by rotary spraying. The degassing time was 10 min, and then allowed to stand for 10 min, and the hydrogen content was measured to be 0.20 ml/100 g. The melt temperature was 710 ° C and was poured.

The metal type 1 is a serpentine runner, and the filling is smooth, effectively preventing the molten metal from filling too fast, causing defects such as turbulence, gas, splash, oxidation, and the like. The metal type 2 is a cast aluminum alloy metal type tensile sample mold which is spontaneously developed. The mold type is an under-injection type, and the mold has a large riser and wear resistance in addition to all the advantages of the metal type 1. The feeding effect of the piece is better, and the defects caused by the shrinkage of the wear parts are reduced, so that the wear parts have good performance.

It is found through experiments that the mechanical properties of the alloy obtained by metal type 2 are significantly better than those of gravity sand type and metal type 1. The tensile strength is increased by 8% and the elongation is increased by 10.35% compared with gravity sand casting. The tensile strength is higher than that of metal type 1. Increased by 5.03% and elongation increased by 27.82%. The tensile strength of electromagnetic low-pressure sand casting is 4.59% higher than that of gravity sand casting, and the elongation is increased by 17.39%; the tensile strength of metal type 1 is increased by 1.68%, and the elongation is increased by 35.97%. The comprehensive performance of the test bar under electromagnetic low-pressure casting is comparable to that of metal type 2. The tensile strength of electromagnetic low-pressure casting is 3.30% lower than that of metal type 2, but the elongation is increased by 6.38%.https://www.wuxiorient.com/