jiachuancasting Yeni Üye
Kayıt Tarihi: 2022-22-Nisan Ülke: Avustralya
Aktif Durum: Pasif Gönderilenler: 2
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Gönderen: 2022-22-Nisan Saat 11:53 | Kayıtlı IP
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casting/">Carbon cast steel is a kind of steel material, and carbon is the main element that affects the mechanical properties of carbon cast steel. With the increase of carbon content, both the yield point and tensile strength of carbon cast steel increased, and the tensile strength increased more than the yield point. In addition, as the carbon content increases, the ductility and toughness of carbon cast steel decrease. When the carbon content in carbon cast steel exceeds 0.45%, the yield point rises very little, while the ductility and toughness decrease significantly. As the carbon content increases, the solidification temperature of carbon cast steel decreases, and the fluidity and casting properties of molten steel become better. Compared with iron/">cast iron, carbon cast steel has poor casting performance. Carbon cast steel has a high freezing point, poor fluidity, large solidification shrinkage, and high inhalation, so it is easy to form pores, sl*g inclusions, shrinkage holes, looseness, hot cracking, cold cracking and cold insulation. Higher casting temperatures can be used to improve fluidity, and larger casting risers can be used to compensate for solidification shrinkage. Carbon steel castings are not suitable for direct use due to their low as-cast plasticity and toughness. In order to improve the properties of carbon steel castings, heat treatment is often required to refine the grains, eliminate the Widmanstler structure and casting stress, and improve the mechanical properties. Carbon steel castings with complex shapes that are prone to deformation and cracking should be annealed; carbon steel castings with simple shapes and not too large wall thickness should be normalized; carbon steel castings with larger sizes generally use After normalizing, tempering treatment; carbon steel castings with simple shapes and high mechanical properties should be quenched and tempered. Annealing or normalizing is generally carried out before the quenching and tempering treatment, and some are directly quenched and tempered in the as-cast state. The latter has the advantages of simple process, short production cycle and low cost. During heat treatment, the heating rate of carbon steel castings with large size or complex shape should not be too fast, otherwise the carbon steel castings will easily cause deformation or cracking. The heating rate of large carbon steel castings is generally limited to 50-100°C/h, and the small ones can be controlled at 100-200°C/h. The annealing and normalizing temperature of carbon steel castings should be appropriately higher than that of carbon steel hot-worked parts of the corresponding grades, and the holding time should be appropriately longer to ensure uniform composition and structure.
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