Low-carbon X80 pipeline steel plate roll and manufacturing method thereof

Abstract

The invention provides a low-carbon X80 pipeline steel plate roll. The chemical components of the low-carbon X80 pipeline steel plate roll comprise, by mass percentage (wt%), C<=0.035%, 1.60%<=Mn<=1.90%, Si<=0.30%, 0.050%<Nb<=0.075%, 0.010%<=Ti<=0.020%, 0.20%<=Mo<=0.30%, 0.20%<=Ni<=0.60%, 0.15%<=Cu<=0.30%, 0.15%<=Cr<=0.30%, S<=0.0025wt%, P<=0.0100wt%, and N<=0.0040wt%, wherein 0.60%<=Mo+Cr+Ni+Cu<=1.10%; the microscopic structure contains more than 90% of acicular ferrite and smaller than 5% of granular bainite; and the typical value of the yielding strength is 580 MPa, the typical value of the tensile strength is 680 MPa, and the typical value of the Charpy V type impact energy under -30 DEG C is 400 J.

Description

technical field [0001] The invention belongs to the field of manufacturing micro-alloyed steel, and in particular relates to a low-carbon X80 pipeline steel coil and a manufacturing method thereof. Background technique [0002] Coal-to-gas refers to the gas containing combustible components obtained from coal as raw material through pressurized gasification followed by desulfurization and purification. The pipeline steel used in the manufacture of coal-to-gas pipelines should have excellent weldability, a certain degree of HIC resistance and low temperature impact toughness. Chinese patent 200910061568.3 discloses a low-carbon, high-niobium-chromium-based high-strength, high-toughness pipeline steel coil and its manufacturing method. Its chemical composition is calculated by weight percentage: C=0.01-0.06, Si=0.10-0.40, Mn=1.00-1.80 , P≤0.018, S≤0.004, Ti=0.005~0.030, Nb=0.08~0.18, Cu≤0.30, Mo=0.08~0.20, Cr=0.10~0.35, A1=0.01~0.06, N=0.002~0.008, The patent application att...

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Problems solved by technology

However, no strengthening element molybdenum (Mo) was added in the above process, and the effect of the strengthening element molybdenum (Mo) was completely ignored. Spiral submerged arc welded pipe for pipeline engineering

Chinese patent 201210050196.6 discloses a X70 grade anti-large deformation pipeline steel plate with excellent toughness and its preparation method. Its chemical composition is calculated by weight percentage: C: 0.03-0.08%, Si: 0.10-0.45%, Mn: 1.40-1.69% , P: ≤0.015%, S: ≤0.005%, Alt: 0.01~0.06%, Nb: 0.01~0.05%, Ti: 0.004~0.014%, N: <0.008%, H: <0.0002%; in the above steel The composition can also contain Mo: 0.00-0.30%, Ni: 0.00-0.30%, Cr: 0.00-0.30%, Cu: 0.00-0.30%. The steel uses a small amount of alloying elements, and the metallographic The structure is mainly composed of the first phase composed of fine-grained ferrite, and also contains the second phase of one or more components in carbide, pearlite, bainite, and martensite. The proportion of the first phase 50-70%, resulting in low strength, can only reach X70 level, and low temperature toughness is not enough

Chinese patent 201510227327.7 discloses a production method of pipeline steel, the chemical composition of which is calculated by weight percentage: C=0.02-0.03, Si=0.20-0.30, Mn=1.00-1.20, P≤0.015, S≤0.005, Nb=0.04 ~0.05, Ti=0.008~0.02, Cu=0.10~0.15, Ni=0.10~0.15, Mo=0.10~0.15, this patent uses low carbon and low alloy elements, which has good low temperature toughness and HIC resistance, but the strength is low , cannot meet the requirements of X80 coal gas pipeline steel

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