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Forgings study on forging quality of forging plant

Edit: Jingjiang Jinlun Machine Manufacturing Co.,Ltd    Date: May 18, 2017

 Forgings Forging parts forging the quality of the study of the production of forgings, in addition to the required shape and size must be guaranteed, but also must meet the parts in the use of the proposed performance requirements, including: strength indicators, plasticity index, impact toughness, fatigue toughness And anti-stress corrosion performance requirements, high temperature work parts, as well as high temperature instantaneous tensile properties, durability, creep resistance and thermal fatigue properties. And the performance of the forging depends on its organization and structure (hereinafter referred to as the organization). Different materials, or the same material of different states of forging, its performance is different, in the final analysis are determined by its organization. The organization of the metal is related to the chemical composition of the material, the smelting method, the pressure processing process and the process. Among them, the pressure processing process has a significant impact on the organization of forgings, especially for those in the heating and cooling process is not the same isomerization of materials, such as: austenitic and ferrite heat-resistant stainless steel, high temperature alloys, And magnesium alloys, etc., mainly rely on the pressure processing process, the correct control of thermodynamic process parameters to improve the organization of forgings and improve its performance. The use of pressure processing methods, but also can improve the surface state of parts and the establishment of surface preload stress, improve the use of parts performance. As the quality of forgings and raw material quality, forging process and heat treatment process, so to ensure high quality forgings, must be from the above aspects of analysis and research.

  The following three issues to discuss: (1) materials and forging process on the organization and performance of the impact of forgings;

  (2) common defects in the forging process;

  (3) the content of the forging quality inspection and the method of forging quality analysis.

  Forgings First, the raw materials and forging process on the organization and performance of forging (a) the impact of raw materials on the organization and performance Forging raw materials for the ingot, rolling, extrusion and forging billet. The rolling material, extruded material and forging are the ingot by rolling, extrusion and forging after the formation of semi-finished products. For the ingot, the charge composition, smelting method and forging process is an important part of determining its quality. And rolling, extrusion and forging processing process, it is decided to the corresponding part of the quality of semi-finished products. Raw materials before entering the forging process, subject to the size, surface quality, chemical composition, high power organization, low power and mechanical properties of the test, in line with technical requirements before they can put into production. The chemical composition of raw materials, high power organization, low power consumption and mechanical properties are the basis for ensuring the microstructure and properties of forgings, and the size and surface quality of raw materials directly affect the plasticity and forming of forgings. In addition, the malleability of raw materials and their recrystallization characteristics are the basis for determining the forging process parameters. Therefore, the good quality of raw materials is a prerequisite for ensuring the quality of forgings. However, the quality inspection of raw materials has some limitations (such as: missed and sampling is not representative, etc.), raw materials, technical conditions of the test method, it is impossible to steel all the internal quality problems are exposed, such as: Internal composition and segregation. Therefore, the existence of various defects in raw materials, will inevitably affect the forging process and the final quality of forgings. The influence of chemical composition and impurity elements in the technical conditions of raw materials, the chemical elements are provided with the corresponding composition range, the impurity elements S, P, Cu, Sn, Pb, etc. also have some restrictions. Chemical elements beyond the provisions of the range and the excessive content of impurities in the forging of the forming and quality will have a greater impact. S, B, Cu, Sn and other elements easy to form a low melting point phase, so that forging prone to hot brittle. The amount of Al has a certain effect on the intrinsic grain size of alloy structural steels. In order to obtain the essence of fine grain steel, steel residual aluminum content to be controlled within a certain range (such as: Al acid 0.02 ~ 0.04%). Aluminum content is too small, can not achieve the role of control grain growth; Excessive, pressure processing in the formation of fiber under the conditions of easy to make grain fracture, tear marks, etc., which will reduce the mechanical properties of the forging and performance. In the 1Cr18Ni9Ti austenitic stainless steel, Ti, Si, Al, Mo content is more, the ferrite phase more, forging the more easy to form surface cracks, and make parts magnetic.


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