C90-1级耐腐蚀石油套管用钢25CrMoTi的开发

通过100 t DC电弧炉-LF-VD-5流260 mm×340 mm连铸-轧制流程开发了石油套管(φ139.7 mm×7.72 mm)用钢25CrMoTi(/%:0.23～0.29C、0.15～0.35Si、0.50～0.70Mn、0.015～0.035Ti、≤0.015P、≤0.003S、0.50～0.70Cr、0.25～0.35Mo、0.010～0.025Alt)。通过电弧炉配加50%铁水,控制钢中有害元素As+Sn+Pb+Sb+Bi≤0.035%,高碱度渣(CaO)/(SiO₂)=4精炼,控制S]≤0.002%,VD真空处理后喂Ti线,并进行钙处理,控制Ca/S为1.5～2.0,连铸全程保护浇铸,采用结晶器和末端电磁搅拌,管坯中心疏松为1.0级,一般疏松、中心偏析为0.5级,各类非金属夹杂物≤0.5级。在H₂S饱和溶液中720 h的应力腐蚀试验后钢管表面无裂纹,满足C90-1石油套管的使用要求。

Development of Steel 25CrMoTi for C90-1 Grade Anti-Corrosion Petroleum Casing Tube

The steel 25CrMoTi（/%:0.23～0.29C,0.15～0.35Si,0.50～0.70Mn,0.015～0.035Ti,≤0.015P,≤0.003S,0.50～0.70Cr,0.25～0.35Mo,0.010～0.025Alt） for petroleum casing tube（Φ139.7 mm×7.72 mm） has been developed by 100 t DC arc furnace-LF-VD-5 strand 260 mm×340 mm bloom casting-rolling process.With adding 50%hot metal in arc furnace steelmaking to control the deleterious elements content in steel（As+Sn+Pb+Sb+ Bi≤0.035%）,refining with high basicity slag-（CaO）/（SiO₂） =4 to controlS]≤0.002%,after VD process feeding Ti wire and carrying out calcium treatment to control Ca/S = 1.5～2.0,whole process shield casting and using M-EMS and F-EMS,the rating of tube bloom central porosity is 1.0,the rating of general porosity and the rating of central segregation are 0.5,and the rating of each kinds of inclusions is≤0.5.After stress corrosion test in saturated H₂S solution for 720 h the tube surface hasn’t crack that meets the requirement for service of C90-1 grade petroleum casing tube.