The spiral steel pipe has a very important role in our lives. The following is based on the thermal treatment process of the spiral steel pipe to introduce the common defects of each process.
(1)Defects generated during heating.For the heating process, the heating equipment and heating medium must be selected.What may occur here may occur here that the surface of the parts will be affected by the oxidized heating medium, and the heating temperature will exceed the process requirements.The Ao's crystal grains are too thick and even melted in the crystal world, which will seriously affect the appearance and internal quality of the parts.Therefore, in the actual process, feasible measures should be taken for such defect analysis.
(2) The defects produced during quenching the small diameter spiral tube.The parts cooled after heating and the austeniticization to obtain the required structure and mechanical properties.At this time, based on the materials and ratio of parts, you need to choose the ideal cooling medium. The ideal cooling medium is to quickly cool down at high temperature and slowly cool at low temperature (3o0 ° C).Usually the cooling medium is 5 % to 10 % saline, 5 % to 15 % alkaline water, synthetic cooling agent, water quenching nitrate cooling, alkaline bath, alkaline bath, alkaline baths, water quenching of water, 5 % to 15 % alkaline water, Nitrate bath, chloride salt bath, etc., the cooling performance of these cooling media is very different, especially for salt, alkaline water, oil, alkaline bath, nitrate bath, chloride salt bath, etc.If there is a problem with the performance of the cooling medium, it will decrease (aging), and if it is not found in time, it will become an important source of defects.Insufficient hardness, soft point, deformation difference between quenching cracks and quenching parts are common thermal treatment defects.
(3) The defects that will occur during the recovery process.The parts quench to obtain high -hardness quenching horse austenitic tissue or the lower bell tissue with a slightly lower hardness, but the tissue at this time is unstable and its brittleness is very high.When using in production, it must be adjusted to obtain the required tissue and performance.Therefore, the recovery process parameters will have an important impact on the thermal treatment quality of the parts, such as hardness, crispness of ignition, ignition cracks and other defects. Effective measures must be taken during the recovery process to avoid the above defects.
(4) Surface quenching defects are the overall heat treatment of parts, so the internal and external parts of the parts can obtain the required hardness and requirements.The surface quenching treatment is only used for the surface of the hardening parts, and the core is still structural before processing.Therefore, surface quenching temperature, heating time, and hardening depth will affect the heat treatment of parts to deform and crack, hardness level and service life.
(5) Chemical heat treatment defects of small diameter spiral tubes.The chemical thermal treatment of the spiral tube is to enable the metal or non -metallic atoms on the surface of the part to obtain the heat treatment process of the required surface performance (such as high wear). This process gives the parts of composite materials dual functions and functions.However, if the process formula and process parameter change, etc., will cause parts to deformation and cracking, unsatisfactory structure, unqualified hardness, etc.Therefore, the chemical heat treatment of the part should be fully paid attention to, otherwise the parts will completely disappear the significance of chemical thermal treatment. The heat treatment of parts should be safe, economical and practical, and at the same time, a cool, clean and quiet working environment should be created.
The correct thermal treatment process is to ensure the premise and basis of the quality of thermal treatment of the parts. Once the above quality problems are found, they can be solved from people, machines, materials, methods, links, and inspections.Through analysis and judgment, the root cause of the defect can be found
