Hot continuous rolling production method for 508mm large-diameter extra-thick-wall seamless steel pipe

Abstract

The invention discloses a hot continuous rolling production method for a 508mm large-diameter extra-thick-wall seamless steel pipe. The method comprises the following steps that 1) a blank is put intoan annular heating furnace for heating; 2) when the temperature of the blank is increased to 1230 DEG C and 1250 DEG C, the blank is taken out and punched into a tubular billet; 3) PQF three-roller continuous rolling is carried out on the punched tubular billet through a continuous rolling mill; 4) a pierced billet obtained after continuous rolling is subjected to pipe disengaging, reducing and sizing through a pipe disengaging rack; after sizing, the outer diameter of the steel pipe is 508 mm, and the thickness of the steel pipe is larger than 60 mm and smaller than or equal to 80 mm; and 5)the sized steel pipe is transferred to a cooling bed for cooling. It can be known from the process that according to the hot continuous rolling production method for the 508mm large-diameter extra-thick-wall seamless steel pipe, one-time continuous rolling production of the 508mm large-diameter seamless steel pipe with the thickness exceeding 60 mm is achieved on the premise that a PQF rolling mill does not need to be replaced.

Description

technical field [0001] The invention relates to the field of production of large-diameter extra-thick-wall seamless steel pipes, in particular to a production method for hot continuous rolling of 508mm large-diameter extra-thick-wall seamless steel pipes. Background technique [0002] Large-diameter thick-walled steel pipes have a very wide range of applications, and because of their thicker walls, they can withstand greater pressure. Generally, it can be used as a material for hollow parts, used to withstand pressure and used on important pipelines. Specifically, it can be used as structural pipes for aviation, petroleum geological drilling pipes, pipes for petrochemical industries, etc. When thick-walled steel pipes are used, they must also follow relevant regulations. Therefore, pipes of different specifications must be used for different purposes. This also provides an important prerequisite for the use of thick-walled steel pipes, especially when transportation is more...

AI Technical Summary

Problems solved by technology

However, as the scope of use of 508 large-diameter seamless steel pipes becomes wider and wider, and the use environment of 508 large-diameter seamless steel pipes becomes more and more complex, the current 508 large-diameter seamless steel pipes with a thickness of 60 mm can no longer meet the new conditions of use. At present, for some special industries, the wall thickness of 508 large-diameter seamless steel pipes is required to reach 80mm

However, according to the existing production process, if the PQF rolling mill is still used for production, it is impossible to produce 508 large-diameter seamless steel pipes with a thickness of more than 60 mm. A huge cost is required. In addition, after the replacement of the rolling mill, not only the production process of 508 large-diameter seamless steel pipes with a thickness of more than 60 mm needs to be adapted to the new rolling mill, but also the production process of seamless steel pipes of other diameters also needs to be re-explored and formulated. , which is too costly for the enterprise and cannot be afforded by the enterprise

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