Casting casting processing Steel castings Hardware machinery 304 stainless steel precision casting processing

(1) Definition
Steel castings are metal products obtained by pouring molten steel into a specific mold cavity through a casting process and cooling and solidifying. It is a common casting product. The composition of steel mainly includes iron and carbon, and also contains small amounts of silicon, manganese, sulfur, phosphorus and other elements. According to different uses and performance requirements, its composition can be adjusted, such as adding elements such as chromium and nickel to improve corrosion resistance and heat resistance.
(2) Casting process
Smelting: First, raw materials such as scrap steel and pig iron are put into an electric furnace or other furnace for smelting. During the smelting process, temperature and chemical composition need to be precisely controlled to ensure the quality of molten steel. For example, for high-quality alloy steel castings, the melting temperature may need to reach about 1600°C, and the addition amounts of various alloying elements must be strictly controlled.
Pouring: The molten steel is poured into a pre-made mold at a suitable temperature. The casting mold can be sand mold, metal mold or ceramic mold, etc. Sand casting is the most common method, which has the characteristics of low cost and strong adaptability. When pouring, pay attention to the pouring speed and pouring method to avoid defects such as pores and slag inclusions in the molten steel.
Cooling and solidification: The molten steel gradually cools and solidifies in the mold. The speed of this process also has a great impact on the quality of the steel castings. If the cooling rate is too fast, it may cause cracks in the casting; if the cooling rate is too slow, it will affect production efficiency. Generally speaking, the cooling time should be controlled reasonably according to the size and shape of the casting. The cooling time of large-size castings may last several hours or even longer.
Cleaning and post-processing: After the casting solidifies, it needs to be taken out of the mold and then cleaned to remove excess parts such as sand, pouring risers, etc. on the surface. Later, heat treatment may be required, such as annealing, normalizing, quenching, etc., to improve the mechanical properties of the steel castings, such as increasing strength, toughness, etc.
(3) Performance characteristics
Excellent mechanical properties: steel castings have high strength, hardness and toughness. Its tensile strength can reach several hundred MPa and can withstand large loads. For example, in some key components of heavy machinery, steel castings can withstand huge pressure and impact, such as the hooks of large cranes. Their strength and toughness can ensure that they will not break when lifting heavy objects.
Good wear resistance: Due to its high hardness, steel castings perform well in some situations where wear resistance is required. In mining machinery, such as the crushing parts of crushers, steel castings can resist the wear and tear of ore and extend the service life of equipment.
Variable corrosion resistance: By adding different alloying elements, steel castings can be given varying degrees of corrosion resistance. For example, adding an appropriate amount of chromium can form stainless steel castings, which can resist corrosion by chemicals such as acids and alkalis in equipment in the chemical, food and other industries.

(1) Machinery manufacturing
Heavy machinery: In the fields of heavy machinery such as mining machinery, metallurgical machinery, and construction machinery, steel castings are key structural components. For example, parts such as bucket teeth of excavators, jaw plates of crushers, and rolls of rolling mills are all steel castings. These parts need to withstand huge impact, friction and pressure, and the high strength and high toughness of steel castings can meet their working requirements.
Machine tool equipment: The bed, column, workbench and other components of machine tools can also be made of steel castings. The cast steel bed can provide good rigidity and stability to ensure the accuracy of the machine tool during processing. For example, the bed of a high-precision CNC lathe is made of cast steel. After precision machining, it can effectively reduce the vibration of the machine tool during high-speed cutting and improve the machining accuracy.
(2) Energy and electricity
Power generation equipment: In thermal power plants and nuclear power plants, steel castings are used to manufacture turbine blades, generator frames and other components. Steam turbine blades work in high temperature, high pressure and high-speed rotation environments, and cast steel blades can withstand huge centrifugal force and thermal stress. The generator base requires good magnetic permeability and mechanical strength, and steel castings can meet these performance requirements.
Petrochemical equipment: In the process of oil exploration and chemical production, various reactors, pipelines, valves and other equipment often use steel castings. These equipment need to resist high temperature, high pressure and chemical corrosion, and steel castings can adapt to complex chemical environments through alloying. For example, in hydrogenation reactors in oil refineries, cast steel casings are able to withstand the high pressures inside and the high temperatures generated by chemical reactions.
(3) Transportation
Ship manufacturing: Steel castings are widely used in ship propellers, rudder blades, anchors and other components. The propeller rotates at high speed in the water and needs to withstand huge hydrodynamic forces and corrosion. The strength and corrosion resistance of the cast steel propeller can ensure the normal navigation of the ship. The steel casting of the rudder blade can provide precise steering control and ensure the ship's maneuverability.
Rail transit: In rail transit vehicles such as trains and subways, steel castings are used to manufacture wheels, couplers and other components. Wheel castings need to have high strength and wear resistance to withstand the huge loads and friction during vehicle operation. Coupler steel castings must ensure the reliability and safety of the connection and play a key role in the traction and braking process of the train.