16MnR钢在催化裂化再生环境中的应力腐蚀开裂研究

Stress Corrosion Cracking of 16MnR Steel in FCCU Regeneration Environments

通过U形试样应力腐蚀实验、电化学极化曲线等方法,在模拟催化裂化再生器环境条件下,研究了HNO3-H2SO4-H2O体系中16MnR钢及其焊缝的应力腐蚀行为。结果表明:16MnR钢焊接接头在不同实验条件下均比基材更易产生硝酸盐应力腐蚀开裂,其机理主要是阳极溶解;引入硫酸根和降低pH值均能破坏16MnR钢的保护膜,增大其焊接接头的应力腐蚀敏感性;当溶液的pH值降低至2以下时,材料处于活化状态,发生严重的均匀腐蚀。

The stress corrosion behavior of the weld seam and base metal of 16MnR steel in solution of HNO3-H2SO4-H2O, one of the typical environments of FCCU regenerator, was investigated using U-bend specimen immersion test and electrochemical polarization curves. The results show that the weld seam of 16MnR is more sensitive to nitrate stress corrosion cracking than base metal, its mechanism is anodic dissolution. Both the introduction of sulfate and the slightly reduction of pH can destroy the protective film on 16MnR steel, and increase the corrosion susceptibility of its weld seam. However, when the pH of solution is less than 2, the material is in active state, resulting in a serious of uniform corrosion. Besides the effective methods to slow down the stress corrosion of materials in catalytic cracking regenerator are analyzed in this article.