Ductile iron spheroidizing grade and annealing of ferritic ductile iron

- Dec 08, 2018 -

Ductile iron, which is a specific type of cast iron, is a common and commonly used material, and will be used in many industries and fields. Therefore, it is necessary to have a correct understanding and understanding before it can be used correctly and get good quality finished products. This material should have a role and performance.


1. Ferritic ductile iron in ductile iron

Ferritic ductile iron, which is a specific type of ductile iron, as its name suggests, is a ductile iron with a matrix of ferrite, which can be referred to as ductile iron. This type of ductile iron has a certain strength and good plasticity and good impact toughness, which can be obtained by as-casting or annealing. According to the quality of the casting, the material can be divided into high-temperature two-stage annealing and low-temperature annealing. When the cementite in the as-cast microstructure exceeds 3%, two-stage annealing should be selected. When the cementite does not exceed 3%, low-temperature annealing should be selected.


The high temperature annealing of ferritic ductile iron has an annealing temperature higher than the eutectoid temperature, generally 900 ° C - 960 ° C, and the annealing temperature of the low temperature annealing is 720 ° C - 750 ° C, and the low temperature annealing temperature should not be lower than 720 ° C, so that the ferrite grains can be finer.


2. The main difference between ductile iron and ordinary cast iron

Ductile iron, which is a type of cast iron, so it is subordinate to ordinary cast iron. The main difference between the two is that in graphite form, the graphite in ductile iron is spherical, and the graphite in ordinary cast iron is sheet-like. Therefore, they are different in performance. The strength and plasticity of ductile iron are both Better than ordinary cast iron.


3. What is the spheroidal grade of spheroidal graphite cast iron? Is it possible to weld?

The spheroidization grade of ductile iron mainly reflects the shape of graphite. The higher the spheroidization level, the better the performance, but it cannot be completely determined by the spheroidization level, because the mechanical properties of ductile iron are also closely related to the metallographic structure. At different levels, the requirements for tensile, yielding, elongation, impact and hardness are different.


Ductile iron is a material that can be welded and is used in some high-intensity cast iron equipment, but its welding performance is not as good as gray cast iron. On the welding rod, WE777 special cast iron welding rod with strong versatility is selected for welding to ensure the welding quality. Its welding hardness can reach 185HB.http://xihuafoundry.com/