材料期刊网

通过OM, SEM以及拉伸实验与电化学测试等手段, 研究了高温时效析出金属间相对铸造2507超级双相不锈钢力学及耐蚀性能的影响. 实验结果表明: 材料固溶后经650-950 ℃时效处理, 析出弥散颗粒χ相有提高抗拉强度的作用,σ相却使抗拉强度急剧下降; 二者均使塑性急剧恶化, 拉伸断口均表现为脆性断裂. 在人工海水中, σ相对材料的耐蚀性影响要比$\chi$相弱,其数量越多, 材料耐蚀性越差.

Duplex stainless steel (DSS) has been used widely due to its very excellent combination of mechanical and corrosion resistance properties. However, the use of DSS is limited by their susceptibility to the formation of dangerous intermetallic phases, such as χ phase and phase, resulting in the detrimental effects on mechanical properties and corrosion resistance. With the application of the super duplex stainless steel (SDSS) with a pitting resistance equivalent number more than 40. The harmful effects of intermetallic phases easily precipitated in DSS on mechanical properties and corrosion resistance are a research focus. This paper, based on prior study, investigates the effects of intermetallic phases formed during aging on the mechanical properties and corrosion resistance of cast 2507 super duplestainless steel by means of optical microscope (OM), scanning electron microscope (SEM), tensile test and electrochemical test. The results indicate that for the solution annealing cast 2507 super duplex stainless steel aged in the temperature range 650—950 ℃, small and depressive distribution χ phase precipitatd from ferrite can increase its tensile strength, but σ phase causes the opposing effect on its plasticity owing to precipitated along grain boundaries. Both of them can rapidly deteriorate its plasticity, and cause brittle failure. The effect of σ phase on corrosion resistance of 2507 SDSS is weaker than phase. The more the σ phase is, the worse the corrosion resistant could be.