ForgingThe raw materials used are ingots, rolled materials, extruded materials and forging billets. The section billet is used to forge large forgings, and rolled, extruded and forged billets are semi-finished products formed by rolling, extrusion and forging of ingots respectively. For ingots, the composition of the charge, the smelting method and the forging process are important links in determining its quality. The rolling, extrusion and forging processes are another link that determines the quality of the corresponding semi-finished products.
Before the raw materials enter the forging process, they need to be inspected for size, surface quality, chemical composition, high magnification structure, low magnification structure and mechanical properties, and can only be put into production after meeting the requirements of technical conditions.
The chemical composition, high magnification structure, low magnification structure and mechanical properties of raw materials are the basis for ensuring the microstructure properties of forgings, and the size and surface quality of raw materials directly affect the process plasticity and forming of forgings. In addition, the malleability of the raw material and its recrystallization characteristics are determinedForgingThe basis of process parameters.
Therefore, the good quality of the raw materials is a guaranteeLarge forgingsPrerequisites for quality. However, the quality inspection of raw materials has certain limitations (such as: missing detection and sampling is not representative, etc.), and the inspection methods specified in the technical conditions of raw materials cannot expose all the quality problems inside the steel, such as: internal composition and segregation. The various defects of raw materials will inevitably affect the forming process of large forgings and the final quality of forgings.
The influence of raw materials on the structure and performance of large forgings mainly includes the following aspects: 1Effect of chemical composition and tramp elements;2.The impact of internal defects in raw materials;3.Effect of surface defects in raw materials;4.The effect of the flow of raw materials.