Abstract：The crack defects in portal frame steel Q440C used for forklift trucks were analyzed.The results showed that the flange crack defects were originated from the corner cracking of the continuously cast billets.In order to solve the cracking problem, various measures were taken.The viscosity （1 300 ℃）, alkalinity （1 300 ℃） and melting speed （1 350 ℃） of the slag were adjusted from 0.96, 0.75 and 51 to 1.55 Pa·s, 0.96 and 47 s, respectively.The amplitude vibration frequency was adjusted from 6 270 μm and 65 cpm to 5 560 μm and 88 cpm.Two the secondary cooling water ratio was reduced from 0.40 to 0.25 L/kg.The primary cooling water flow of the mold increased from 145 to 155 m3/h.The influent temperature increased from 25- 28 to 30- 33 ℃.The drawing speed was improved from 0.60- 0.65 to 0.70- 0.75 m/min.Finally, the crack problem of the Q440C door frame shaped steel flange was solved.
丰年. Q440C级门架型钢翼缘裂纹成因分析及解决措施[J]. 中国冶金, 2018, 28(7): 73-77.
FENG Nian. Cause analysis and solution of cracking problem in gantry profile flange of steel Q440C[J]. China Metallurgy, 2018, 28(7): 73-77.
2018, Vol. 28 
