Hot-rolled sheet coils of X80 pipe line steel and manufacturing method thereof

Abstract

The invention discloses hot-rolled sheet coils of X80 pipe line steel and a manufacturing method thereof. The steel comprises the following chemical components by weight percent: 0.02-0.06% of C, 0.05-0.35% of Si, 1.70-1.90% of Mn, not more than 0.015% of P, not more than 0.004% of S, 0.20-0.35% of Cr, 0.06-0.15% of Mo, 0.06-0.11% of Nb, not more than 0.08% of V, not more than 0.20% of Ni, not more than 0.25% of Cu, 0.005-0.025% of Ti, 0.015-0.045% of Als, 0.001-0.004% of Ca, not more than 0.006% of N and the balance Fe and inevitable impurities. The cold cracking susceptivity coefficient Pcm is not more than 0.21%. The manufacturing method is characterized in that the continuous casting slabs are directly subjected to hot charging at 500-850 DEG C and are discharged after being heated to 1150-1250 DEG C, the final rolling temperature of rough rolling is 1030-970 DEG C, the final rolling temperature of finish rolling is 750-850 DEG C, the compression ratio of finish rolling is more than 60% and the sheet coils are rapidly cooled at the speed of 10-25 DEG C / s by way of laminar cooling and are coiled at 450-580 DEG C. In the invention, hot charging rolling is adopted, thus improving the service efficiency of heat, saving energy, shortening the production cycle, improving the production efficiency and greatly lowering the production cost.

Description

technical field [0001] The invention belongs to the field of manufacturing high-strength low-alloy steel, and in particular relates to an X80 pipeline steel and a manufacturing method thereof, in particular to a hot-rolled coil of X80 pipeline steel for manufacturing spiral submerged arc welded steel pipes in the API SPEC 5L specification and its Manufacturing method. Background technique [0002] Pipeline transportation is the most economical, safe, efficient and environmentally friendly transportation method for long-distance transportation of oil and natural gas. With the optimization and adjustment of the global energy structure, the demand for oil and natural gas energy is increasing, which stimulates the rapid development of pipeline construction. [0003] In order to reduce pipeline construction and operation costs and improve transmission efficiency, the development of long-distance pipelines to use high-grade, high-pressure, and large-diameter transmission has becom...

AI Technical Summary

Problems solved by technology

Solve the problem of adding precious alloy elements to the alloy design in the prior art, and the thick gauge continuous casting slab is used in the manufacturing process, the slab needs to be finished off-line before the continuous casting slab is reheated, the heat loss is large, the production cycle is long, and High production costs and many other problems

Images