{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T04:05:05Z","timestamp":1785470705824,"version":"3.56.0"},"reference-count":53,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2025,8,6]],"date-time":"2025-08-06T00:00:00Z","timestamp":1754438400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["52374320"],"award-info":[{"award-number":["52374320"]}]},{"name":"National Natural Science Foundation of China","award":["U23A20606"],"award-info":[{"award-number":["U23A20606"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>To address the central cracking problem in continuous casting slabs of 38CrMoAl steel, high-temperature tensile tests were performed using a Gleeble-3800 thermal simulator to characterize the hot ductility of the steel within the temperature range of 600\u20131200 \u00b0C. The phase transformation behavior was computationally analyzed via the Thermo-Calc software, while the microstructure, fracture morphology, and precipitate characteristics were systematically investigated using a metallographic microscope (MM), a field-emission scanning electron microscope (FE-SEM), and transmission electron microscopy (TEM). Additionally, the effects of different holding times and cooling rates on the microstructure and precipitates of 38CrMoAl steel were also studied. The results show that the third brittle temperature region of 38CrMoAl steel is 645\u20131009 \u00b0C, and the fracture mechanisms can be classified into three types: (I) in the \u03b1 single-phase region, the thickness of intergranular proeutectoid ferrite increases with rising temperature, leading to reduced hot ductility; (II) in the \u03b3 single-phase region, the average size of precipitates increases while the number density decreases with increasing temperature, thereby improving hot ductility; and (III) in the \u03b1 + \u03b3 two-phase region, the precipitation of proeutectoid ferrite promotes crack propagation and the dense distribution of precipitates at grain boundaries causes stress concentration, further deteriorating hot ductility. Heat treatment experiments indicate that the microstructures of the specimen transformed under water cooling, air cooling, and furnace cooling conditions as follows: martensite + proeutectoid ferrite \u2192 bainite + ferrite \u2192 ferrite. The average size of precipitates first decreased, then increased, and finally decreased again with increasing holding time, while the number density exhibited the opposite trend. Therefore, when the holding time was the same, reducing the cooling rate could increase the average size of the precipitates and decrease their number density, thereby improving the hot ductility of 38CrMoAl steel.<\/jats:p>","DOI":"10.3390\/ma18153703","type":"journal-article","created":{"date-parts":[[2025,8,6]],"date-time":"2025-08-06T15:09:53Z","timestamp":1754492993000},"page":"3703","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Influence of Heat Treatment on Precipitate and Microstructure of 38CrMoAl Steel"],"prefix":"10.3390","volume":"18","author":[{"given":"Guofang","family":"Xu","sequence":"first","affiliation":[{"name":"School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shiheng","family":"Liang","sequence":"additional","affiliation":[{"name":"School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiangtao","family":"Chen","sequence":"additional","affiliation":[{"name":"Wuhu Xinxing Ductile Pipe Co., Ltd., Wuhu 241002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yabing","family":"Zhang","sequence":"additional","affiliation":[{"name":"Wuhu Xinxing Ductile Pipe Co., Ltd., Wuhu 241002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaotan","family":"Zuo","sequence":"additional","affiliation":[{"name":"Wuhu Xinxing Ductile Pipe Co., Ltd., Wuhu 241002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-8680-8768","authenticated-orcid":false,"given":"Zihan","family":"Li","sequence":"additional","affiliation":[{"name":"HBIS Material Technology Research Institute, Shijiazhuang 052160, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Song","sequence":"additional","affiliation":[{"name":"School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0023-2368","authenticated-orcid":false,"given":"Wei","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,6]]},"reference":[{"key":"ref_1","unstructured":"(2016). 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