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通过Gleeble-3800焊接热模拟试验机,对S32750双相不锈钢焊接热影响区(HAZ)进行了热模拟试验,并对试样显微组织进行观察,对硬度、冲击等力学性能进行检测,研究峰值温度对HAZ组织和性能的影响规律。结果表明,热影响区主要组织为奥氏体+铁素体,峰值温度在850~1 000℃范围内时,HAZ组织中出现了σ相;随着峰值温度升高,奥氏体含量逐渐降低,铁素体含量先略有下降然后逐渐升高,σ相含量则是先略有增加后逐渐下降,当峰值温度达到1 050℃以上时几乎完全消失;HAZ硬度先略有升高,峰值温度为900℃时最高390 HV,随后硬度逐渐降低;冲击功则先略有下降,900℃时达到最低值60 J,随后冲击功又逐渐升高,1 100℃时冲击功大幅提高至102 J。
The thermal simulation test was carried out on the heat-affected zone (HAZ) of S32750 duplex stainless steel by Gleeble-3800 welding simulator. The microstructure of the sample was observed and the mechanical properties such as hardness and impact were tested. The peak value Influence of temperature on microstructure and properties of HAZ. The results show that the main microstructure of HAZ is austenite + ferrite. When the peak temperature is in the range of 850-1000 ℃, the σ phase appears in the HAZ microstructure. With the increase of the peak temperature, the austenite content gradually decreases , The content of ferrite decreases slightly and then increases gradually, while the content of σ phase increases first and then decreases gradually. When the peak temperature reaches above 1 050 ℃, the content of ferrite decreases almost completely. The hardness of HAZ first slightly increases, and the peak temperature The maximum hardness was 390 HV at 900 ℃, and then the hardness decreased gradually. The impact energy first decreased slightly and reached the lowest value at 60 ℃ at 900 ℃. Then the impact energy increased gradually and the impact energy increased sharply to 102 J at 1 100 ℃.