碳和硼含量对低碳冷镦钢连铸坯高温力学性能的影响

试验的低碳冷镦钢(/%:0.14~0.20C,≤0.20Si,0.3~1.0Mn,≤0.030P,≤0.035S,0~0.001 9B)连铸坯的生产流程为80 t BOF-LF-280 mm×325 mm坯连铸工艺。通过Gleeble-3500热模拟机研究了0.14%~0.20%C和0~0.001 9%B对该冷镦钢600~1 200℃力学性能的影响。结果表明,该钢第Ⅲ脆性区为700~900℃,当钢中C含量较高时,最低塑性的温度较低,硼促使该钢700~950℃脆性区出现两个低谷,但当硼含量增加到0.001 9%时,该钢的高温塑性得到改善。在850~1 200℃,各试验钢的塑性良好,适合较大程度的变形,矫直温度和热加工温度宜控制在850℃以上。

Effect of Carbon and Boron Content on Mechanical Properties of Casting Bloom of Low Carbon Cold Heading Steel at Elevated Temperature

The production flowsheet for casting bloom of test low carbon cold heading steel (/% :. 0.14 ~0.20C, ≤0.20Si, 0.3 ~ 1.0Mn, ≤0.030P, ≤0.035S, 0 ~0.001 9B) is 80 t BOF-LF-280 mm x 325 mm bloom casting process. The effect of 0. 14% ?0. 20% C and 0 ~ 0. 001 9% B on mechanical properties of the cold heading steel at 600 ~ 1 200 °C has been studied by using Gleeble-3500 thermal simulation machine. Results show that the III brittle zone of the steel is 700 ~ 900 ℃, as the C content in steel is higher the temperature of minimum plasticity of steel is lower； the boron promotes to occur of two valleys in 700 ~ 950℃ brittle zone, but as the B content in steel is up to 0. 001 9% , the elevated temperature plasticity of steel is improved. At 850 ~ 1 200 ℃ each test steel has better plasticity to be suit for larger deformation, therefore straightening and hot-working temperature should be controlled at more than 850 °C.