| WU Gang,LI De-jun,LUO Jin-heng,BAI Qiang,LI Li-feng,ZHU Li-xia.Erosion Mechanism of Weld Joint of 16Mn Pipeline Steel[J],49(3):205-212 |
| Erosion Mechanism of Weld Joint of 16Mn Pipeline Steel |
| Received:February 15, 2019 Revised:March 20, 2020 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2020.03.026 |
| KeyWord:16Mn pipeline steel weld height fluid simulation erosion corrosion deformation wear cutting effect |
| Author | Institution |
| WU Gang |
CNPC Tubular Goods Research Institute State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
| LI De-jun |
CNPC Tubular Goods Research Institute State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
| LUO Jin-heng |
CNPC Tubular Goods Research Institute State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
| BAI Qiang |
CNPC Tubular Goods Research Institute State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
| LI Li-feng |
CNPC Tubular Goods Research Institute State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
| ZHU Li-xia |
CNPC Tubular Goods Research Institute State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an , China |
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| Abstract: |
| The work aims to explore the erosion mechanism of weld surface by studying the excess height of weld and the fluid action of pipe body since the surface erosion behavior of 16Mn pipeline steel joint-pipe body weld is one of the main causes of failure in pipeline works. 16Mn pipeline steel was taken as the object to carry out basic research on the erosion behavior of the weld zone. The corrosion behavior of the initial fluid weld zone was studied by electrochemical and corrosion simulation experiments, and the influence of residual weld height and fluid velocity on the erosion process of the weld zone was investigated by fluid simulation experiments, which revealed the erosion mechanism of the weld of pipeline steel. In corrosion simulation experiment, the open circuit potentials of weld, joint and tube were -0.717, -0.686 and -0.687 V, respectively. The tendency of electrochemical corrosion in weld zone was the highest in simulated corrosion solution. The self-corrosion current density of the weld was 7.9 μA/cm2, and that of the base metal was 3.2 μA/cm2. The electrochemical corrosion tendency of the weld was greater. Due to the high corrosion rate of the metal in the weld zone, loose FeO product layer was formed on the surface of the weld. In the fluid simulation experiment, the turbulent flow was formed by the residual height of the weld, and the turbulent kinetic energy increased with the increase of the flow rate. When the flow rate was 15 mm/s and 30 m/s, the depth of the weld groove was 3 mm and 8 mm respectively, and the difference of the weld groove was 5 mm. Turbulence energy produced deformation wear and cutting effects on the surface of corrosion products of FeO in excess height of weld, which made the loose FeO product layer on the surface of weld peel off, accelerated the corrosion process, and finally formed erosion depression area. The erosion behavior of 16Mn pipeline steel weld is the result of the interaction of corrosion and fluid erosion. It can be divided into two stages: initial corrosion and fluid erosion, forming the cyclic alternating process of corrosion and erosion. The excess height of weld and fluid velocity has great influence on erosion. The increase of excess height of internal weld and fluid velocity will lead to a sharp increase of turbulent kinetic energy at excess height, accelerate the stripping of corrosion product layer of weld metal, and lead to erosion of weld surface. The research results can provide theoretical basis for failure behavior and safe service design of pipeline. |
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