油缸用25Mn钢100 t EAF-LF-VD-软吹氩-CC流程B类夹杂物的控制

衡钢采用硅钙脱氧工艺、控制EAF钢水中全氧含量、LF渣系中Al₂O₃含量、控制精炼时间≥40 min、VD真空脱气、软吹时间≥20 min、保护浇注防止钢水二次氧化和促使钢中夹杂物上浮等应用工艺措施,可有效降低钢水中B类夹杂物Al₂O₃数量和尺寸以提高钢的洁净度。生产实践表明:油缸钢生产中精炼炉控制钢水Al]s≤0.004%、TO] ≤0.002 0%、精炼终渣（FeO） ≤0.8%、碱度（R）控制在2.0～3.2有利于B类夹杂物控制。当B类夹杂物不超过1.0级有利于控制刮滚工艺"白点"的产生。

Controlling of Grade B Inclusion in 100 t EAF-LF-VD-Soft Ar Browing-CC Flowsheet in 25Mn Steel for Hydraulic Cylinder

The measures as applying the process of Si-Ca deoxidation, controlling the total content of oxygen in the EAF molten steel and the content of Al₂O₃ in LF slag,Control refining time ≥40 min,vacuum degassing(VD),control soft blow time ≥20 min, and protecting cast to prevent secondary oxidation of the molten steel and promote the floating o£ inclusions in the steel are adopted at Hengsteel. The number and size of Grade B inclusion Al₂O₃ in the molten steel are reduced to improve the cleanliness of steel. Production practice shows that controlling steel Al]s≤0.004% ,TO] ≤0.0020% , refined final slag (FeO) ≤0.8% and alkalinity (R) between 2.0 and 3.2 in liquid of hydraulic cylinder steel are available to control Grade B inclusion. Grade B inclusions not exceeding class 1.0 is beneficial to control the production of " white spots" in the SRB process.