X120 pipeline steel submerged arc straight weld pipe and manufacture technique thereof

Abstract

The invention discloses a longitudinal submerged arc welded pipe made of X120 pipeline steel and a process for manufacturing the same. The chemical compositions by percentage of the X120 pipeline steel are: 0.04 to 0.06 percent of C, 1.85 to 1.95 percent of Mn, 0.2 0 to 0.30 percent of Si, less than or equal to 0.012 percent of P, less than or equal to 0.0005 percent of S, 0.06 to 0.08 percent of Nb+V+Ti, 1.0 to 1.2 percent of Ni+Cr+Cu, 2.7 to 3.0 percent of Cr+Mo+Mn, 0.0010 to 0.0014 percent of B, 0.048 to 0.52 percent of Ceq, 0.18 to 0.20 percent of Pcm. The longitudinal submerged arc welded pipe is made of a controlled rolled multi-element low alloy high-strength X120 steel plate through the procedures of edge milling, prebending, JCO molding, prewelding, internal welding, external welding, expanding, chamfering, etc. The steel pipe formed by the invention is much more approximate to a round shape, realizes high-speed welding and improves working efficiency, with the welding process ensuring the internal quality and external quality of the steel plate. The invention is used to manufacture longitudinal submerged arc welded pipe for transporting oil and gas.

Description

technical field [0001] The invention belongs to the field of metal iron and steel, and in particular relates to an X120 pipeline steel, a produced straight seam submerged arc welded pipe and a manufacturing process thereof. Background technique [0002] Pipeline transportation is the most reasonable transportation method for long-distance transportation of oil and gas. It has the remarkable characteristics of economy, safety, high efficiency, energy saving, uninterrupted, and less damage to the environment. Therefore, all countries in the world attach great importance to the development of pipeline transportation technology, and many countries spare no effort to spend a lot of financial and material resources to vigorously develop the pipeline transportation industry. Pipeline transportation has become the fifth largest transportation industry after road, railway, waterway and air transportation. [0003] The development trend of pipeline construction is towards long-distan...

AI Technical Summary

Problems solved by technology

At present, there is no report on the production of X120 high-strength steel pipe by JCOE method; there are foreign reports that X120 steel pipe has been developed by UOE forming method, but there are many problems, mainly manifested in the decrease of strength and toughness of weld metal and heat-affected zone, The specified technical requirements are not met, and due to the limitation of the forming method, the roundness of the pipe is not satisfactory