一种双相不锈钢热处理工艺的优化

对一种双相不锈钢设计并进行了不同的热处理,研究了不同热处理后双相不锈钢的组织、相结构、硬度及在几种腐蚀介质中的腐蚀特性.结果表明:提高固溶温度可略提高双相不锈钢的硬度而基本不影响其耐蚀性;固溶后时效使δ相中析出σ相,一些δ相转变为γ相,钢的硬度显著增加.阳极极化实验表明时效后双相不锈钢的耐蚀性较固溶态降低,降低程度与腐蚀介质有关;在1 mol/L NaCl中,时效后双相不锈钢的耐蚀性剧烈降低;但时效对双相不锈钢在0.2 mol/L H2SO4与1 mol/L H3PO4中的钝化区基本无影响.由于材料的腐蚀磨损抗力与其耐蚀和耐磨能力均有关,因此在一定服役条件下,可以通过时效适当提高双相不锈钢的硬度来提高其腐蚀磨损抗力.

Optimizing heat treatment for a duplex stainless steel

Different heat treatments were employed on a duplex stainless steel (DSS).The microstructure,phase,hardness and corrosion behavior of the treated DSS in several aggressive media were investigated.The results show that increasing solution temperature increases hardness slightly and no significant influences on corrosion resistance of the solution-treated DSS is observed.Sigma phase precipitates from δ phase and some δ transforms to γ during the following ageing.As a result,hardness of the aged DSS increases obviously.Anodic polarization test reveals that the corrosion resistance of the aged DSS is lower than that of DSS only solution-treated.The decreasing extent is influenced by the corrosion media.In 1 mol/L NaCl solution,the corrosion resistance of the aged DSS is reduced dramatically,while almost no influence is observed in the passivation zone of the anodic polarization curves in 0.2 mol/L H2SO4 and 1 mol/L H3PO4 solution.As corrosive wear resistance of material depends on both anti-corrosion and anti-wear ability,it is suggested that corrosive wear resistance of DSS in specific service condition can be improved by properly increasing hardness with an appropriate heat treatment.