Method for producing medium and small aperture seamless steel tube by reducing and rolling hollow continuous cast tube blank

Abstract

The invention discloses a method for producing a medium and small aperture seamless steel tube by reducing and rolling a hollow continuous cast tube blank. The technical process thereof is as follows: utilizing a large-scale round blank heating furnace to heat a hollow tube blank to 1050-1200 DEG C; after discharging the tube pipe out of the furnace, carrying out high-pressure descaling on the tube blank so as to remove scale on the surface of the tube blank; transmitting the tube blank to the front desk of an elongator through a rollgang, aligning with the center of the hole pattern of the elongator, and enabling a push rod trolley to move towards the inlet direction of the elongator so as to lead the push rod to penetrate into the blank; causing the rollgang to rotate so as to feed the blank into the elongator; utilizing the elongator to carry out rolling, wherein the wall thickness of the blank is reduced to the needed wall thickness, the outer diameter is reduced to the needed diameter, the diameter reducing rate of the blank reaches 60%, and the wall reducing rate reaches 96%; and utilizing the rollgang to feed a hollow billet into a cooling bed for cooling, and feeding the hollow billet into a three-roller longitudinal rolling tensile force reducing and sizing unit for reducing and sizing rolling, thereby finally obtaining the needed dimension. The invention lowers the perforation process, and solves the eccentric perforation problem caused in the process of perforating solid core blanks.

Description

technical field [0001] The invention relates to a rolling process of a seamless steel pipe, in particular to a production method for producing a small-caliber seamless steel pipe by using a large hollow pipe billet. technical background [0002] The current seamless steel pipe rolling process is roughly divided into the following types: piercing with a piercer, rolling through a two-roll or three-roll continuous rolling mill, and reducing and sizing through a reducing and sizing unit to achieve the final required size ; There is also piercing through a piercing machine, and reduction and wall reduction are carried out through a two-roll or three-roll skew rolling mill, but the range of reducing the diameter and wall is very small. The final required size; in addition, it is pierced by a piercing machine, rolled by an automatic pipe rolling machine, leveled by a leveling machine, and finally reduced and sized by a reducing and sizing unit to achieve the required size. [000...

AI Technical Summary

Problems solved by technology

[0004] 1. The length of the tube blank is limited by the length of the ejector rod in the background of the piercing machine, thus limiting the length of the finished product and affecting the metal yield

[0005] 2. Because the length of the tube blank is limited, the production capacity of the production line is limited

[0006] 3. Because the current production process requires piercing of solid tube blanks, the rolling temperature is greatly increased, which greatly increases the fuel consumption for heating, and at the same time increases the power consumption during the piercing process

[0007] 4. Due to the perforation process, the probability of partial penetration is increased, so that the possibility of uneven wall thickness of the steel pipe is greatly increased, and the wall thickness deviation of the steel pipe is increased.

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