Homogeneity evaluation on chemical composition, microstructure and mechanical properties of heavy-forged CLF-1 steel plate

Abstract

Homogeneity evaluation on chemical composition, microstructure and mechanical properties was performed on heavy-forged CLF-1 steel plate for CN HCCB TBM module R&D application. The material featured excellent homogeneity in chemical composition throughout the layer-thickness direction. Impurities and active elements concentrations were maintained very low. No significant microstructure difference was observed. Results of microhardness, tensile and impact properties exhibited negligible thickness effect. Yield strength and ultimate tensile strength of the material reached over 520 MPa and 650 MPa at room temperature, respectively, and the total elongation and reduction in area were measured to be over 25% and 75%, respectively. The material also showed desirable toughness, with an impact energy of roughly 250 J at room temperature, and the DBTT was identified to be 193–200 K. The 130 mm-thick CLF-1 steel heavy plates have been adopted in R&D of CN HCCB TBM module, considering their high level of composition and microstructure homogeneity, as well as isotropic mechanical properties.