Effect of Center Segregation of Hot-Rolled Rod on Mechanical Properties of Oil-Quenched and Tempered Spring Steel 55SiCrA

• Published in: Teshugang
• Main Authors: Meng Yaoqing, Zheng Yongrui, Li Yongjun, Zhao Haoqian, Wang Wei
• Format: Article
• Language: Chinese
• Published: Editorial Office of Special Steel 2015-08-01
• Subjects: Spring Steel 55SiCrA; Center Carbon Segregation; Oil-Quenching and Tempering; Mechanical Properties
• Online Access: http://www.specialsteeljournal.com/thesisDetails?columnId=129794693&Fpath=home&index=0

The production flowsheet of oil-quenched at 890 ℃ for 300 s and tempered at 530℃ for 1200 s Φ22 mm rod of spring steel 55SiCrA (/% : 0.55C, 1.45Si, 0.67Mn, 0.010P, 0.005S, 0.68Cr) is hot metal desulphurization- 80 t top and bottom combined blowing converter- LF- RH- 280 mm x 325 mm bloom casting-Φ22 mm rolling products. Examination results show that the center segregation rating of Φ22 mm rolled products of steel 55SiCrA is 3 , the carbon content at center of rod is non-homogeneous i. e. 0.50%-0.60% C, and the carbon content at 1/2 radius of rod is 0.54% ; of steel specimen at center the tensile strength is 1430-1455 MPa and the reduction o£ area is 39%-40% , while of steel specimen at 1/2 radius of rod the tensile strength is 1470-1480 MPa and the reduction of area is 43.0%-45.5% , the serious center segregation ( rating 3) leads to obvious decrease of mechanical properties of oil-quenched and tempered spring steel 55SiCrA.