Cause analysis of unqualified elongation rate of seamless steel pipe after breaking

In the production process of seamless steel pipe, a phenomenon of unqualified elongation rate after breaking occurs from time to time. This may be caused by the following reasons:
    
Firstly, the material models of seamless steel pipes with unqualified elongation rate after breaking may not meet the actual requirements. When selecting steel materials for seamless steel pipes, special attention should be paid to the requirements of residual elements, which should be selected according to the grade or production conditions of the seamless steel pipe. If the selected material properties can not meet the predefined indicators, the elongation rate of steel pipes after breaking will be poor.
    
Secondly, the defects in technology such as poor annealing or improper rolling process in the production of seamless steel pipes will have a negative impact on the elongation rate of steel pipes after breaking. Poor annealing can cause the coarsening of the ferrite grain size of the metallographic structure of seamless steel pipe, reduce its ductility and plasticity, and cause poor elongation rate of steel pipe after breaking. The improper rolling process will cause the uneven deformation of the billet, which will also lead to the bad elongation rate of steel pipe after breaking.
    
Thirdly, the problems of excessive internal stress generated by improper heat treatment, unreasonable welding process and foreign body left in the inner wall of the pipe will affect the elongation rate of steel pipe after breaking. Excessive internal stress will make the steel pipe itself easy to generate deformation, reduce its tensile strength, and thus lead to poor elongation rate.
    
In general, in order to effectively avoid the occurrence of unqualified elongation rate of seamless steel pipe after breaking, we should pay close attention to the rationality of material selection and reasonability of technology. Moreover, we should also establish corresponding inspection standards and regulations, to ensure the uniformity and reliability of production processes and products.
    
At the same time, the organization and methods of the production process should also be reasonably matched. In actual production, attention should be paid to prevent the occurrence of failures, detect and eliminate potential safety hazards in time, to ensure the good performance of seamless steel pipe products.

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