煨制弯管成形工艺对L360Q钢组织和性能影响

The Influence of Bending Tube Forming Process on the Microstructure and Properties of L360Q Steel

  • 摘要: 本文采用热弯曲试验方法,通过对L360Q钢直无缝钢管局部感应加热弯制及回火热处理,系统分析了弯管不同部位的硬度、拉伸性能及夏比冲击强度,并观察了金相组织结构,同时对比分析了热弯和热处理前后L360Q钢的力学性能。试验结果表明,由于加热过程中温度分布不均,导致弯管各部位形变量存在差异,进而使组织和性能存在差异。弯管过渡区起弧段抗拉强度为588Mpa、屈服强度为520Mpa,其强度明显高于原始母材(直无缝钢管)以及弯管其他部位;在起弧段和收弧段附近区域,硬度值高于管体其他部分;原始母材在经过热弯和回火热处理后,其金属延伸率会有所降低,但韧性总体变化差异并不明显,表明热弯和回火热处理对钢管的韧性影响有限。本研究的热弯成型与热处理工艺符合 GBT 9711-2017 和 SY5257-2012 标准要求,为L360Q管线弯管设计提供了技术储备与参考。

     

    Abstract: This article adopts the hot bending test method to systematically analyze the hardness, tensile properties, and Charpy impact strength of different parts of L360Q seamless steel pipes through local induction heating bending and tempering heat treatment. The metallographic structure is observed, and the mechanical properties of L360Q steel before and after hot bending and heat treatment are compared and analyzed. The experimental results indicate that due to uneven temperature distribution during the heating process, there are differences in the deformation of various parts of the bent pipe, which in turn leads to differences in microstructure and properties. The tensile strength of the transition zone of the bent pipe at the beginning of the arc is 588 MPa, and the yield strength is 520 MPa, which is significantly higher than the original base material (straight seamless steel pipe) and other parts of the bent pipe; In the vicinity of the starting and ending arc sections, the hardness value is higher than that of other parts of the pipe body; After undergoing hot bending and tempering heat treatment, the metal elongation of the original base material will decrease, but the overall change in toughness is not significant, indicating that the effect of hot bending and tempering heat treatment on the toughness of steel pipes is limited. The hot bending and heat treatment process of this study meets the requirements of GBT 9711-2017 and SY5257-2012 standards, providing technical reserves and references for the design of L360Q pipeline bends.

     

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