Production technology of API 5L X60 PSL1 pipeline steel

API 5L X60 PSL1 pipeline steel is widely used in the field of long-distance transportation of oil and natural gas. As API 5L X60 PSL1 pipeline steel requires good impact toughness and DWTT performance, low carbon + niobium composition design is generally adopted, and controlled rolling + controlled cooling technology is adopted to obtain corresponding microstructure.

Due to the bad control of the rolling shape of the API 5L X60 PSL1 pipeline steel plate after adding Nb, the shape of the rolled steel plate is not good. After being cooled by ACC, the API 5L X60 PSL1 pipeline steel plate further deforms, resulting in the flatness of the steel plate exceeding the standard, which can not meet the delivery requirements. Even if the API 5L X60 PSL1 pipeline steel plate is leveled by the hot straightener, the steel plate will deform during cooling on the cooling bed, resulting in the flatness exceeding the standard seriously. At the same time, due to the serious deformation, the steel plate can not pass through the flaw detector and shear, so the API 5L X60 PSL1 pipeline steel plate can only be lifted to the front of the cold straightener for leveling, and then lifted back to the shear machine for shearing and flaw detection. In this way, the production efficiency is seriously reduced and the manufacturing cost is greatly increased, which requires a lot of extra manpower and material resources.

At present, the pre straightener and ultra fast cooling are generally used to improve the shape and performance of the pipeline. However, the pre straightener and ultra fast cooling need a large investment, which will increase the manufacturing cost. BBN steel has studied upgraded API 5L X60 PSL1 pipeline steel production method, thus not only the production strength meets the requirements, but also the toughness is good.