Of machinery parts and components used in our daily will always lead to serious wear and tear, because all sorts of reason and worn parts if continue to use may cause some serious consequences, so in order to ensure the service life of equipment, we usually use nodular cast
iron to replace the worn parts.
And nodular cast iron
parts need, manufacturers have to know every nodular cast iron.
1, the graphite shape: nodular cast iron, as the name implies, the representative of the graphite spheroidal shape.
The quality of ductile iron are typically spheroidization rate to assess.
Graphite more roundness, small, distribution more uniform, should be caused by fragmentation effect of metal matrix and volume of the smaller, the better the performance of ductile iron.
According to GB/T9441 nodular cast iron metallographic examination requirements, graphite shape is divided into six levels, level 3 or more qualified, spheroidization rate to reach more than 75%.
2, the matrix organization: nodular cast iron matrix organization varies according to the brand.
I plant with ball iron matrix was mainly composed of ferrite and pearlite, also includes a small number of cementite, phosphorus eutectic.
Casting ferrite content more, less pearlite content, good toughness, low intensity;
The opposite high strength, toughness is poor.
The commonly used QT400 -
10 brands in ferritic ductile iron as the main substrate, pearlite content to control below 20%.
Cementite, phosphorus eutectic plant in these two groups in the use of ductile iron is harmful, needs to be controlled under 2%, otherwise the casting strength and toughness is poor.
After 3, casting organization unqualified remedy: if casting adverse or phosphorus eutectic graphite spheroidizing, late is beyond repair, so it is necessary to effective quality control of production process.
If cast pearlite and cementite in overweight, can also through the low temperature, high temperature annealing heat treatment means such as remedy.
4, ductile iron pieces of manufacturing process quality control and inspection: ductile iron parts due to the need of molten iron, spheroidizing treatment, process quality control is very important.
Has been the raw materials into the factory laboratory, to work;
Secondly to test before furnace, composition of strict control;
According to molten iron weight adding appropriate amount of inoculant and spheroidizing agent;
We will strictly control each pack of molten iron pouring time, prevent the pouring to late graphite recession.
A pack of hot metal casting sample to late to do mechanical properties test and metallographic examination.
Iron acceptance criteria on the mechanical properties and casting sample to late to do performance testing can be found in a timely manner the casting presence of inoculation, spheroidizing quality problems such as poor or graphite recession.
In addition, the winter season is casting quality problem, because of the low temperature will cause the molten iron cooling too fast, too supercooled graphite or pearlite, and after the winter hot metal pouring so attention should be paid to the casting of heat preservation.
In addition, ductile iron parts in addition to do mechanical properties test and metallographic examination, qualified fracture of ductile iron, percussive sound also has a characteristic very much, experienced inspectors can take advantage of these two methods preliminary inspection of the casting quality and prevent nonconforming batch.
Factory workers casting mature technology strength our factory has accumulated rich experience in casting, pay attention to product technology, production of the product quality is stable.
Guangzhou Xinerxun Metal Trading Co., Ltd. highlighted the need to foster a human openness to technological innovation.
Reach us at Xin Wilson Foundry. We'll always try to give you the BEST deal on . If we can't, we'll at least give you some hel pful advice. Please use our experience!
Guangzhou Xinerxun Metal Trading Co., Ltd. has great reputation with an excellent selling record for fulfilling customer's satisfaction.