典型碳钢高压锅炉管带状组织成因及其对持久强度的影响

Cause of Band Structure in Typical Carbon Steel High Pressure Boiler Tube and its Influence on Endurance Strength

简述碳钢带状组织的形成机理,分析不同炼钢工艺对热轧SA210Gr.C、20G碳钢高压锅炉管带状组织的影响,研究轧制过程中带状组织的变化情况,以及带状组织对钢管持久强度的影响。分析认为:采用小规格管坯轧制及模铸锻造工艺,降低Mn含量,能够在一定程度上减轻轧制后钢管的带状组织;在轧制过程中,即使终轧温度在1 000℃以上,带状组织依然明显;带状组织对持久强度略有影响,但即使存在较严重带状组织的钢管,其持久强度依然能够满足相关标准要求,且有较大富余量。

The formation mechanism of band structure in carbon steel is introduced and the influence of different steelmaking processes on band structure in hot-rolled SA210Gr.C and 20G carbon steel high pressure boiler tubes are analyzed. The changing status of the band structure during the rolling process and the influence of the band structure on the creep rupture strength of the tubes are studied. The analysis shows that by adopting the small size billets and the mold casting and forging process, and lowering the content of Mn, the band structure in the rolled tubes may be alleviated to a certain degree. It is found that even when the finishing temperature is above 1 000 ℃, the band structure is still obvious. The band structure has slight influence on endurance strength, but even for tubes with severe band structure, their endurance strength can still meet the relevant standard requirements with big margin.