The test adopts 500 kg medium-frequency induction furnace melting, and the process of fusing vermicular cast iron. The vermicular cast iron is self-made, and the specific composition is shown in Table 1. The capacity of vermicular graphite cast iron vermicular ladle is about 70~80 kg. In order to improve the absorption rate and ensure the vermicular effect, about 60 kg of molten iron is processed in each ladle and 9 packets are processed in one furnace. The suitable adding range of vermicularizing agent for vermicular graphite cast iron with certain S content was studied by testing the vermicularizing rate, pearlite content, mechanical properties and composition.
Furnace burden
steel scrap
Pig iron Z14
50
Dosage/kg
450
Package times
Vermicularizing agent/%
Cu/%
Sn/%
Inoculant/%
1
0.8
0.5
0.04
0.6
2
1.0
0.5
0.06
0.6
3
1.2
0.5
0.09
0.6
4
0.7
0.7
0.04
0.6
5
0.7
0.7
0.06
0.6
6
0.7
0.7
0.09
0.6
7
0.6
0.9
0.04
0.6
8
0.6
0.9
0.06
0.6
9
0.6
0.9
0.09
0.6
The furnace charge shall be weighed according to Table 2. During the test, two Y-shaped test blocks (made according to the national standard GB/T26655-2011), one composition sample and two rapid metallographic samples (one at the beginning and one at the end) were poured in each package. In order to ensure the success rate of the test, the first three packs of vermicular graphite cast iron vermicularizing agent are added according to the predetermined amount of low, medium and high. After treatment, check the poured Φ The vermicular rate of vermicular graphite cast iron of 12 mm cylinder sample was found to be too low (almost nodular iron). In order to ensure a high vermicular rate of vermicular graphite cast iron, the amount of vermicular graphite cast iron vermicular agent was appropriately reduced. The fourth to sixth packs of vermicular graphite cast iron vermicular agent was added at 0.7% (0.42 kg), and the seventh to ninth packs of vermicular graphite cast iron vermicular agent was added at 0.6% (0.36 kg). The test scheme is shown in Table 3. The test data such as the actual pre-furnace addition and pouring temperature are shown in Table 4.
