These 6 golden principles for selecting ductile iron castings
that will be mentioned in today's Dyfeng science class
1. Principles for the selection of carbon and carbon equivalents
Carbon is the basic element of ductile iron,
high carbon is helpful for graphitization,
and the upper limit of carbon equivalent in ductile iron
is based on the principle that no graphite floats.
2. The selection principle of silicon
Silicon is a strongly graphitizing element.
In ductile iron, silicon can not only effectively reduce
the tendency of white mouth and increase the amount of ferrite,
but also can refine the eutectic group and
improve the roundness of graphite spheres.
After the carbon equivalent is selected,
the principle of high carbon and
low silicon strengthening is generally adopted.
The lower limit of silicon is based on
the principle that free cementite does not appear.
3. The selection principle of manganese
Since the content of sulfur in ductile iron is already very low,
there is no need for too much manganese to neutralize sulfur.
The role of manganese in ductile iron is
mainly to increase the stability of pearlite and
promote the formation of carbonized manganese and iron.
Therefore, the manganese content in ductile iron is
generally as low as possible
(except for medium manganese ductile iron and
bainite ductile iron for the purpose of improving wear resistance).
Due to time reasons,
the remaining 3 golden principles for selecting ductile iron castings
will be told to you in the next issue~
that will be mentioned in today's Dyfeng science class
1. Principles for the selection of carbon and carbon equivalents
Carbon is the basic element of ductile iron,
high carbon is helpful for graphitization,
and the upper limit of carbon equivalent in ductile iron
is based on the principle that no graphite floats.
2. The selection principle of silicon
Silicon is a strongly graphitizing element.
In ductile iron, silicon can not only effectively reduce
the tendency of white mouth and increase the amount of ferrite,
but also can refine the eutectic group and
improve the roundness of graphite spheres.
After the carbon equivalent is selected,
the principle of high carbon and
low silicon strengthening is generally adopted.
The lower limit of silicon is based on
the principle that free cementite does not appear.
3. The selection principle of manganese
Since the content of sulfur in ductile iron is already very low,
there is no need for too much manganese to neutralize sulfur.
The role of manganese in ductile iron is
mainly to increase the stability of pearlite and
promote the formation of carbonized manganese and iron.
Therefore, the manganese content in ductile iron is
generally as low as possible
(except for medium manganese ductile iron and
bainite ductile iron for the purpose of improving wear resistance).
Due to time reasons,
the remaining 3 golden principles for selecting ductile iron castings
will be told to you in the next issue~
