稀土元素Ce对A36船板钢耐腐蚀行为的影响

Effect of RE Element Ce on Behavior of Corrosion Resistance of A36 Steel Plate for Shipbuilding

试验用A36和含Ce的A36Ce船板钢(/%:0.12~0.13C,0.21Si,0.77~0.79Mn,0.013~0.015P,0.003~0.004S,0.32~0.33Cr,0.023~0.025Al,0~0.009Ce)由真空感应炉熔炼,铸成7 kg锭,锻成25 mm×25 mm方坯,并经865℃0.5 h空冷的正火处理。通过对普通不含Ce的A36船板钢和含0.009%Ce的A36Ce船板钢在模拟海水(3.5%NaCl)环境中的全浸试验,用失重、电化学方法、扫描电镜和X-射线衍射法分析了两钢种腐蚀速率,腐蚀形貌和锈层特征。结果表明,在海水中浸蚀30天后,A36船板钢的腐蚀速率为1.8 g/(mm^2·天),A36Ce船板钢的腐蚀速率为1.2 g/(mm^2·天);A36Ce船板钢易形成黑色较致密的内锈层,且不易脱落;普通A36船板钢点腐蚀倾向较严重,而A36Ce船板钢以均匀腐蚀为主;两种钢腐蚀产物主要为铁的氧化物和羟基铁。

Test normal A36 steel and containing Ce A36Ce steel for shipbuilding （/% ： 0. 12 - 0. 13C, 0. 21Si, 0. 77 --0. 79Mn, 0. 013 -0. 015P, 0. 003 -0. 004S, 0. 32 ～0. 33Cr, 0. 023 N0. 025A1, 0 N0. 009Ce） are melted by vac- uum induction furnace, cast to 7 kg ingot, forged to 25 mm × 25 mm billet and normalized at 865 ℃ for 0. 5 h. The corro- sion rate, corrosion surface morphology and features of rust layer of both normal non-containing Ce A36 steel plate for ship- building and containing 0. 009% Ce A36Ce plate for shipbuilding are analyzed by full immersion examination in simulated seawater （3.5 % NaC1） environment with using weight loss, electrochemical method, scanning electron microscope and X- ray diffractometry. Results show that in seawater for 30 day, the corrosion rate of A36 steel plate for shipbuilding is 1.8 g/ （mm2 ~ day）, while that of A36Ce steel plate for shipbuilding is 1.2 g/（ mm2 · day） ; the A36Ce steel plate is easily to form denser black inner rust layer which is not easily to peel off; the pitting corrosion tendency of normal A36 steel plate is more severe, but the uniform corrosion of A36Ce steel plate is primary ; the corrosion products of both steels are iron oxide and carbonyl.