Steel pipe normalizing furnace

Abstract

The invention relates to a steel pipe normalizing furnace, which belongs to the technical field of metal pipe processing kilns and comprises a furnace body of an open flame continuous heat treatment furnace, wherein one end of a furnace hearth of the furnace body of the open flame continuous heat treatment furnace is a burning heating heat insulation region with a smoke discharge opening, the other end of the furnace hearth is a cooling region, and the burning heating heat insulation region and the cooling region are communicated through a narrow neck passage. The steel pipe normalizing furnace is characterized in that a preheating air heat exchange mechanism used for pre-heat-exchange purposes on high-temperature smoke gas from the smoke discharge opening is matched and connected onto the smoke discharge opening, a cooling smoke gas inlet pipe used for introducing the cooled smoke gas into the cooling region is arranged on the cooling region, and a smoke gas cooling mechanism is matched and connected onto the cooling smoke gas inlet pipe, is connected with the preheating air heat exchange mechanism and is used for receiving the preheated smoke gas from the preheating air heat exchange mechanism. The steel pipe normalizing furnace has the advantages that the steel pipe normalizing can be completed in the furnace, so the defect of environment influence can be overcome, and in addition, the steel pipe normalizing furnace also has the advantage that the resources and the energy sources are saved.

Description

technical field [0001] The invention belongs to the technical field of metal pipe processing kilns, and in particular relates to a steel pipe normalizing furnace. Background technique [0002] Normalizing, also known as normalization, is a metal heat treatment process in which the workpiece is heated to 30-50 °C above Ac3 or Accm, and after a certain period of time, it is taken out of the furnace and cooled in the air or sprayed with water, sprayed or blown. Its purpose is to Make grain refinement and carbide distribution uniform. The difference between normalizing and annealing is that the cooling rate of normalizing is faster than that of annealing, so the normalizing structure is finer than that of annealing, and its mechanical and physical properties are also improved. The aforementioned Ac3 refers to the final temperature at which free ferrite is completely transformed into austenite during heating; the aforementioned Accm is the critical temperature line for complete ...

AI Technical Summary

Problems solved by technology

Although high-temperature air-cooling has the advantages of not occupying equipment and high production efficiency, there are the following technical problems: First, the surface quality of the steel pipe is difficult to guarantee, because the steel pipe is exposed to the air medium and air-cooled in the high-temperature state after being released from the furnace, which is easy to damage the surface of the steel pipe. Rapid oxidation, and bark-like oxide scales, accompanied by oxidation and blistering in severe cases; second, waste of resources, such as rectangular steel pipes with a wall thickness of 4 mm, after being air-cooled in the air medium outside the furnace, double-sided ( Inner and outer walls) the oxidation thickness is generally 0.04mm, resulting in a steel consumption of 10‰ (ten thousandths); the third is to increase the follow-up treatment process and easily cause environmental pollution, because, in order to remove the surface oxide scale (oxidized layer), it is necessary to pass Pickling process Pickling, grinding or shot blasting is carried out after pickling, which not only increases the cost of the aftermath process, but also damages the environment, especially the improper disposal of pickling waste liquid; the fourth is the mechanical properties of steel pipes It is not guaranteed and the consistency is poor, because the heat treatment of steel pipes is arranged in multiple branches, and the air cooling outside the furnace is affected by uncontrollable factors such as wind force, near wind, far wind, shade and sun, so it is objectively difficult to guarantee normalization The mechanical and physical properties of the treated steel pipe are consistent; the fifth is a waste of energy, which is specifically manifested in the low utilization rate of waste heat in the process, which is contrary to the current society's advocacy of conservation and energy-saving economic spirit

[0004]Of course, if the steel pipe is heat-treated in an open flame heating continuous heat treatment furnace and transferred to a separately configured normalizing furnace with a protective atmosphere (such as nitrogen), Then the above oxidation phenomenon can be effectively curbed, but choosing this method will greatly increase the processing cost

[0005] Undoubtedly, implementing furnace normalization in an open flame heating continuous heat treatment furnace can completely eliminate the aforementioned five points, but in the published patent and non-patent There is no corresponding or referenced technical inspiration in the literature

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