Defects caused by improper cooling after forging
Cooling cracks:
The cracks are smooth and slender, sometimes in the form of mesh cracks. High magnification observation: martensitic structure appears near the crack, and there is no trace of plastic deformation. It mostly occurs on martensitic steel forgings. Due to the rapid cooling after forging, large thermal stress and structural stress are generated. Slow cooling in a sandpit or slag around 200°C can prevent such cracks.
Cooling deformation:
Large, thin-walled, thin-ribbed frame members, warping deformation during post-forging cooling. It is caused by the interaction of residual stress generated in forging and stress caused by uneven cooling. Annealing immediately after forging can prevent such defects.
475℃ brittle crack:
Surface cracks appear when ferritic stainless steel is cooled too slowly after forging, and the residence time is too long in the temperature range of 400-520 °C. Due to the long residence time at 400-520 °C, a special substance is precipitated and brittleness is caused. Fast cooling at 400-520°C can prevent cracks.
Mesh Carbide:
Carbides are precipitated in the form of a network along the grain boundaries, which reduces the plasticity and toughness of the forgings. This defect is often seen in steel forgings with high carbon content. Due to the slow cooling after setting, the carbides can be folded along the grain boundaries, which makes the forgings easy to crack during quenching and deteriorates the performance of the parts.
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Keva Casting is a professional casting company that focuses on Construction, Machinery, Automobile, Hardware, Pipeline and many other industries.
We provide top quality products with the best service based on our complete production chain including our own mold design, advanced production techniques, and full management of the supply chain. Keva Casting has two factories located in Zhucheng, China's Shandong province.
We use "shell molding", which is a new technique that has been developed in recent years.This new technique has simplified production procedures and reduced air pollution compared with traditional sand casting and investment casting. Shell making and core making are faster to ensure production in enormous quantities. The dimensions and surface finishing are satisfactory for all kinds of industrial requirements. Besides supplying our own formwork & scaffolding systems, our casting products also supply OEM services in various industries.