Abstract Ultra-high temperature geothermal wells (>450 °C) have a large potential for increased energy yield as compared to conventional high-temperature geothermal wells (200-300 °C), but several research challenges must be resolved before robust operation in this temperature range can be achieved. In this study, yield- and tensile strength data for several relevant carbon steels and corrosion resistant alloys are generated as a step on the way to enable design of collapse- and tensile capacity for geothermal casings exposed to temperatures up to 500-550 °C. The experiments extend the data set listed in NZS 2403:2015 by providing data for higher temperatures and different material classes. It is found that the carbon steels follow the same near linear decay in strength as the NZS 2403:2015 curves up to 350 °C, and then display a significant drop in tensile strength at higher temperatures, particularly for the lower strength steels. The alloys with high nickel content work harden significantly more than the carbon steels at high temperatures and they tend to retain their strength at temperatures above 350 °C. The tested titanium alloy shows high yield strength and low work-hardening at 500 °C and in contrast to the tested nickel alloys, do not display dynamic strain ageing.

中文翻译：

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地热套管材料热机械拉伸试验

摘要 与传统的高温地热井（200-300°C）相比，超高温地热井（>450°C）在提高能源产量方面具有巨大潜力，但在该领域的稳健运行之前必须解决一些研究挑战。可以达到的温度范围。在这项研究中，生成了几种相关碳钢和耐腐蚀合金的屈服和抗拉强度数据，作为设计暴露于 500-550 °C 温度下的地热套管的坍塌和抗拉能力的一步。这些实验通过提供更高温度和不同材料类别的数据，扩展了 NZS 2403:2015 中列出的数据集。发现碳钢在强度上遵循与 NZS 2403:2015 曲线相同的近线性衰减，直至 350 °C，然后在较高温度下显示出抗拉强度的显着下降，特别是对于强度较低的钢。镍含量高的合金在高温下的加工硬化程度明显高于碳钢，并且在 350 °C 以上的温度下它们往往能保持其强度。测试的钛合金在 500 °C 下显示出高屈服强度和低加工硬化，与测试的镍合金相比，不显示动态应变时效。