Nodularizer and spheroidizing elements in the role of nodular cast
ing' target='_blank'>cast iron
production while at home and abroad, many different kinds of nodularizer, but in our country at present the application or rare earth magnesium alloys, most of this kind of alloy elements and spheroidizing is mainly discussed.
Spheroidizing and anti-spheroidizing elements of the role of the so-called spheroidizing spheroidizing elements are those that can promote the spheroidal graphite, graphite ball to generate or increase the elements.
Spheroidizing elements generally has the following properties: (together
Elements on the outer shell with one or two valence electrons, lining have eight electrons.
The electronic structure elements and sulfur, oxygen and carbon has strong affinity, reflect the product is stable, can significantly reduce the discount of sulfur and oxygen.
Low solubility in molten iron, elements tend to significantly segregation in solidification process.
Although there are certain affinity and carbon, but low solubility in graphite lattice.
According to the above characteristics, Mg, Ce, Y, Ca belongs to the spheroidizing elements effectively.
Is a high vapor pressure in the molten iron, molten iron Buddha teng.
Magnesium atomic weight and density is smaller than the molten iron and melting point of 650 degrees, the boiling point of 1108 degrees, under the processing temperature of the molten iron, magnesium produces high vapor pressure (
More than 1 mpa)
Magnesium melting heat for 21 j/g, the latent heat of evaporation is 406 j/g.
Therefore, magnesium in molten iron, to produce vaporization, the molten iron.
Second, oxygen and sulfur, has a strong affinity.
The generated MgO style and the MgS high melting point, density and far less than iron, easily separated from the molten iron, therefore of molten iron, magnesium content of sulfur and sheep are low;
3 it is to have segregation in solidification process of molten iron in the tendency of graphite, when the residue in the molten iron more than 0.
035%, can at the end of the ball, but when magnesium residues more than 0.
, with 07% of the magnesium segregation in the grain boundary, and the grain boundary of carbon, phosphorus and other exothermic reaction, generate MgC2, Mg2C3, Mg3P2 etc.
Residual magnesium quantity is more, intergranular carbides increased.
Rare earths element on the graphite spheroidizing is the significant role of light rare earth element yttrium in cerium and heavy rare earths in the.
One is the boiling point of rare earth elements are higher than magnesium, join the molten iron, do not cause the billow of molten iron and spitting;
Second, cerium and yttrium base of rare earth elements have stronger than magnesium desulfurization deoxidization ability, generate vulcanization of rare earth and rare earth oxide compound high melting point, good stability;
Three is that rare earth elements and molten iron the spheroidizing interference elements can form stable compounds, so than magnesium nodulizing agent containing rare earths nodularizer strong anti-jamming capability.
Rare earth elements residues have obvious effects on the graphite spheroidizing.
Light rare earth treated eutectic molten iron, when residual cerium content is 0.
04%, the graphite spheroidizing, and very stable;
When handling hypoeutectic iron, to increase for the amount of light rare earth.
Light rare earth processing ball iron, graphite roundness than magnesium processing ball iron is poor, and fragmental graphite;
Another light rare earth processing ball iron chilling tendency is big, so you need to control its addition amount.
Yttrium heavy rare earth itself high melting point, the solid sulfur result of oxide and sulfide is stable at high temperatures, therefore its ability to resist spheroidizing recession is very strong.
1400 - degree hot insulation for 1 hour, spheroidization rate reduce does not exceed 10%, sulfur 0.
06% of molten iron, with yttrium base heavy rare earth alloy after processing, can get complete spheroidal graphite.
Molten iron residue yttrium in 0.
15%, the graphite spheroidizing good;
Below this limit, along with the decrease of yttrium once appeared irregular and vermicular graphite;
Residual yttrium more than 0.
15 and below 0.
30%, the chilling tendency increases gradually, graphite roundness, and higher residual YTe4 appeared.
Ca: calcium solubility in the molten iron is low, its effect on microstructure is through the combined with oxygen and sulfur and indirect implementation.
Compared with magnesium, calcium and sulfur, oxygen affinity of stronger, can effective desulfurization oxygen.
Calcium residue is very low, graphite branches tend to increase, the residual amount is large, but reduce size of graphite, branches tend to be lower.
Calcium residue reached 0.
2%, the chilling tendency increase obviously.
As a entrepreneur, being trapped in a company under multiple quality problems never appealed to Guangzhou Xinerxun Metal Trading Co., Ltd..
Guangzhou Xinerxun Metal Trading Co., Ltd. will be known for our leadership edge, through our passion for high standards, our respect for diversity and our commitment to create exceptional opportunities for professional growth so that associates can fulfill their highest potential.
Guangzhou Xinerxun Metal Trading Co., Ltd. will do this by managing our business with integrity and the highest ethical standards, while acting in a socially responsible manner with particular emphasis on the well-being of our teammates and the communities we serve.