Nodular cast iron is a material mainly composed of iron. It has medium strength, medium toughness and good machinability. At low temperature, the toughness changes to brittleness, but the low-temperature impact value is high, and it has certain resistance to sudden temperature changes and corrosion resistance.
二、 Chemical composition of ductile iron QT500-7
三、 Mechanical properties of ductile iron QT500-7 castings
Tensile strength (MPa): ≥500
Conditional yield strength (MPa): ≥320
Elongation (%): ≥7
Hardness ： 170 ～ 230HB
四、 Heat treatment process of ductile iron QT500-7 castings
Ball milled cast iron QT500-7 is a very commonly used material. Generally speaking, a kind of stress relief and tempering is enough for the heat treatment process. After the castings are unpacked and cleaned, the stress relief and tempering is carried out. The temperature of the heat treatment furnace is generally around 500-600 ℃. The castings can be taken out for roughing or semi-finishing operations.
However, there is also a case where due to the different processing accuracy of the product (or the customer's requirements), two stress relief tempers can be performed, and heat treatment is performed before roughing and deburring and after roughing to ensure the casting High precision.
In addition, if it is QT600 or QT700, normalizing + annealing treatment is required. The temperature of the heat treatment furnace is generally around 900 ℃ to ensure that mechanical properties and hardness can be achieved.
五、Ductile iron QT500-7 casting mold
Ductile iron castings generally require molds. We produce nodular cast iron castings in our factory. We will recommend two molds for you. One is the real sample mold, and the other is the template mold.
The real mold is a relatively affordable mold, which is cheap and suitable for customers who purchase less at a time or who will not purchase for a long time. Although the price of the actual mold is affordable, the amount of deformation cannot be accurately controlled. If the deformation of the casting size you need to purchase is very high, we do not recommend that you use the actual mold, we will give you Recommend another economical mold.
The template mold is a product with a supporting plate at the bottom, which can generally effectively control the size of the deformation. Of course, such a good mold is more expensive than the actual price, but its advantage is that it can be used for a long time, meaning that if you still want to purchase the same casting in the future, you do n’t need to Pay the cost of the mold again. Generally speaking, this type of mold can cast about 100 pieces of the same product. Very economical.
六、Use of Ductile Iron QT500-7 Castings
Ductile iron castings are very versatile, such as oil pump gears for internal combustion engines, intermediate temperature cylinder separators for steam turbines, valve bodies for hydraulic turbines, railway locomotive vehicle bushings, machine frame drive shafts, shaft lugs, end covers for large machinery, etc.
Contact Person: Ms. Juliet Zhu