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研究了一种低C、低Mn、高Cr和高Nb低合金钢经控轧控冷及轧后回火处理后性能与组织的变化,并对试验钢进行了抗氢致开裂(HIC)试验。结果表明:与轧态相比,回火处理后试验钢的力学性能有较大提高,600℃左右回火后屈服强度由轧态519MPa增加到626MPa,抗拉强度由653MPa增加到705MPa,且韧性基本未降低,回火处理后组织仍以针状铁素体为主,回火后M/A岛尺寸减少。此外,轧态与回火态钢均能满足抗HIC试验衡量标准,回火处理后抗HIC性能优异。降低Mn质量分数能显著提高低合金钢抗HIC性能,提高Cr质量分数和Nb质量分数能有效强化低Mn钢的强度。
The properties and microstructure changes of a low C, low Mn, high Cr and high Nb low alloy steel after controlled rolling and controlled tempering were studied. The hydrogen induced cracking (HIC) test of the test steel . The results show that the mechanical properties of the test steel after tempering are greatly improved compared with that of the rolled state. After tempering at 600 ℃, the yield strength increases from 519MPa to 626MPa and the tensile strength increases from 653MPa to 705MPa, After the tempering treatment, the microstructure of acicular ferrite was still dominated. The size of M / A island decreased after tempering. In addition, both the as-rolled and tempered steels meet the HIC test criteria and are excellent in HIC resistance after tempering. Reducing the mass fraction of Mn can significantly improve the anti-HIC performance of low-alloy steels, and increasing the Cr mass fraction and Nb mass fraction can effectively strengthen the strength of low-Mn steels.