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Comparison of castings and stainless steel forgings

Update:28 Sep 2018
Summary:

We are familiar with castings, and casting applications […]

We are familiar with castings, and casting applications have a long history. In ancient times, people used castings to make money rituals, weapons, tools, and some living utensils. In modern times, however, castings are mainly used for blanks of machine parts or directly as machine parts. Castings in mechanical products are beginning to take an increasing proportion, and the amount of use is increasing year by year. The shape and variety of castings are constantly changing. Castings have gradually become an indispensable part of our daily life. Various types of door handles, door locks, small water pipes and other occasions can be used to see the use of castings.

Castings have excellent mechanical and physical properties. They can have a variety of different strength, hardness, and toughness properties. They can also have one or more special properties, such as wear resistance, high temperature resistance, low temperature, corrosion resistance, etc. .

Castings are available in a wide range of weights and sizes. The lightest weight is only a few grams, the heaviest is 400 tons, the thinnest wall is only 0.5 mm, the thickest can be more than 1 meter, and the length can range from a few millimeters to a dozen meters. It can meet the requirements of different industrial sectors.

Compare the difference between castings and stainless steel forgings:

1. The casting has good wear resistance and shock absorption function, because the graphite in the cast iron is beneficial to lubrication and oil storage, so the wear resistance is good. Similarly, due to the presence of graphite, the gray cast iron has better shock absorption than steel.

2. The casting process performance is good. Because the gray cast iron has high carbon content and is close to the eutectic composition, the melting point is relatively low, the fluidity is good, and the shrinkage rate is small, so it is suitable for casting complex or thin-walled castings. In addition, due to graphite It is easy to form chip breaking during cutting, so the machinability of gray cast iron is better than steel.

3. Stainless steel can improve its microstructure and mechanical properties after forging. After the hot-formed deformation of the cast structure by the forging method, the original coarse dendrites and columnar grains become the equiaxed recrystallized structure with fine grains and uniform size due to the deformation and recrystallization of the stainless steel, so that the original segregation in the steel ingot, The compaction and welding of loose, stomata and slag inclusions make the structure more compact and improve the plasticity and mechanical properties of the metal.

4. The mechanical properties of castings are lower than the mechanical properties of forgings of the same material. However, the forging process can ensure the continuity of the metal fiber structure, so that the fiber structure of the forging is consistent with the shape of the forging, which can ensure the good mechanical properties and long service life of the parts by precision die forging, cold extrusion, warm extrusion and other processes. The forgings produced are unmatched by castings.

Whether it is casting or stainless steel forgings, it is an indispensable part of mechanical production. In mechanical production, according to different product properties, the corresponding castings or forgings are selected. Only by fully exerting the functions of castings or forgings, can we have perfect mechanical products.