Li Bopeng,Liu Linfeng,Liu Ping,et al.Effect of Hot-Forging Heating Temperature and Time on the Austenite Grain Size of Pseudo-Carburized 20CrMnTi[J].Special Steel,2026,47(04):80-86.
Li Bopeng,Liu Linfeng,Liu Ping,et al.Effect of Hot-Forging Heating Temperature and Time on the Austenite Grain Size of Pseudo-Carburized 20CrMnTi[J].Special Steel,2026,47(04):80-86.DOI: 10.20057/j.1003-8620.N250525.
Effect of Hot-Forging Heating Temperature and Time on the Austenite Grain Size of Pseudo-Carburized 20CrMnTi
In this work, the phase transformation and precipitation behavior of 20CrMnTi steel after forging and the morphology of the prior austenite grain after isothermal normalizing and pseudo-carburizing under different forging heating processes were investigated. Results show that, for the conventional hot-rolled bars, the normal prior austenite grain morphology after carburizing can be obtained under the forging heating process of 1 220 ℃×2, 3, 5 and 10 min. Using the pretreatment, i.e., homogenized by 1 000 ℃×2 h, deformed at 950 ℃ and then furnace-cooled from 700 ℃ to room temperature, (Nb, Ti)C fully precipitated from the hot-rolled state. In order to avoid the abnormal growth of the prior austenite grain after the same isothermal normalizing and carburizing process, the forging heating time at 1 220 ℃ should be no less than 5 min.Under the design of titanium reduction on the surface of test steels with different compositions, ensuring the sufficient re-dissolution of microalloyed carbonitrides through the heating temperature and time before forging can also achieve no mixed grains in the 960 ℃ pseudo-carburizing process. Maximizing the avoidance of excessive precipitation of microalloyed carbonitrides in hot-rolled bars can reduce the temperature and time required for the re-dissolution of microalloyed carbonitrides during the forging heating process in downstream forging plants.
Saito G , Sakaguchi N , Matsuura K , et al . Effects of normalizing temperature on the precipitation of fine particles and austenite grain growth during carburization of Al- and Nb-microalloyed case-hardening steel [J]. ISIJ International , 2023 , 63 ( 4 ): 727 - 736 .
Saito G , Sakaguchi N , Ohno M , et al . Effects of concentrations of micro-alloying elements and hot-forging temperature on austenite grain structure formed during carburization of case-hardening steel [J]. ISIJ International , 2020 , 60 ( 11 ): 2549 - 2557 .