Development of Creep Life Assessment of Martensitic Heat Resistant Steels

马氏体耐热钢蠕变寿命评估的进展

• 批准号: 16360347
• 负责人: NAKASHIMA Hideharu
• 金额: $ 8.51万
• 依托单位: KYUSHU UNIVERCITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360347/
• 关键词: Martensite; Heat resistant steel; Microstructural change; Life assessment; Omega method; SEM; EBSP method; TEM; HAADF-STEM; クリープ損傷

High Cr heat resistant steels are used for main components in the thermal power plants. They have tempered martensitic lath structure and precipitation hardening is an effective strengthening technique for the improvement of their creep strength. In Japan, the thermal power plants which have been operated during over 20 years increase. Therefore, it is important that the creep life time of heat resistant steels is estimated in industry. Many techniques are proposed for the creep life time assessment. An Omega (Ω) method is one of the useful techniques. In this study, in order to develop the creep life assessment of the heat resistant steels, microstructures of Martensitic steels were observed and the creep tests were carried out. In 9Cr-1Mo steels, it was clarified that much amount of block and packet boundaries was reduced just before creep rupture by SEM/EBSP technique. In various 10Cr steels bearing V and Nb, many creep curves were analyzed by Ω method. As the result, it was found that the creep life time which obtained creep tests corresponded to the estimated creep life time by Ω method. The Ω method is very useful to estimate the creep life time for heat resistant steels. In addition, in this study, the effects of addition of V and Nb on Ω were investigated. Creep strength was improved with increasing the V content and was slightly lowered by increasing the Nb content. Q in all the steels bearing V or Nb was larger than that in fundamental steel (no V and Nb). The dependence of Ω on the amount of additions was different between V and Nb. In steels bearing V, Ω became larger with increasing V content. In steels bearing Nb, Ω became smaller. These results revealed that Ω corresponds to the creep strength and indicated that the value of Ω can be estimated using the strengthening effects of the additive elements.

高铬耐热钢是火力发电厂的主要部件。它们具有回火马氏体板条组织，沉淀硬化是提高其蠕变强度的有效强化技术。在日本，已经运行了20多年的火力发电厂不断增加。因此，估算耐热钢的蠕变寿命在工业上具有重要意义。许多技术被提出用于蠕变寿命评估。Omega（Ω）方法是有用的技术之一。为了发展耐热钢蠕变寿命的评估方法，对马氏体钢的显微组织进行了观察，并进行了蠕变试验。在9 Cr-1 Mo钢中，通过SEM/EBSP技术阐明了在蠕变断裂之前大量的块和包边界减少。用Ω法分析了含V、Nb的10 Cr钢的多种蠕变曲线。结果表明，蠕变试验得到的蠕变寿命与Ω法估算的蠕变寿命相吻合。Ω法是估算耐热钢蠕变寿命的有效方法。此外，在本研究中，V和Nb的添加对Ω的影响进行了研究。蠕变强度随V含量的增加而提高，随Nb含量的增加而略有降低。所有含V或Nb钢的Q值均大于不含V和Nb的基础钢。V和Nb的Ω对添加量的依赖性不同。在含V钢中，Ω随V含量的增加而增大。含Nb钢的Ω变小。这些结果表明，Ω对应于蠕变强度，并表明，Ω的值可以估计的添加元素的强化效果。

项目成果

Mechanism of Grain Boundary Fracture of SUS316 Steels at High Temperature

SUS316钢高温晶界断裂机理

• 发表时间: 2005
• 期刊: Report of the 123rd Committee on Heat-Resisting Materials and Alloys, Japan Society for the Promotion of Science Vol.46, No.2
• 作者: M.Mitsuhara;K.Ikeda;H.Nakashima;T.Terachi;K.Arioka
• 通讯作者: K.Arioka

立体集合組織を有する高純度アルミニウム箔中に存在する非立方体方位粒の特徴

三维织构高纯铝箔中非立方取向晶粒的特征

• 发表时间: 2004
• 期刊: 軽金属 54・12
• 作者: 高田尚記;他
• 通讯作者: 他

Creep Life Assessment of High Cr Ferritic Steels by Ω Method and Effects of V and Nb Content on its Parameters

Ω法评估高铬铁素体钢的蠕变寿命及V、Nb含量对其参数的影响

• 发表时间: 2006
• 期刊: Report of the 123rd Committee on Heat-Resisting Materials and Alloys, Japan Society for the Promotion of Science Vol.47, No.2
• 作者: Y.Yoshida;M.Mitsuhara;K.Ikeda;H.Nakashima;T.Wakai
• 通讯作者: T.Wakai

SUS316鋼の高温変形に伴う粒界破壊機構

SUS316钢高温变形沿晶断裂机制

• 发表时间: 2005
• 期刊: 耐熱金属材料123委員会研究報告 : 耐熱鋼分科会 46・2
• 作者: K.Ikeda;K.Fujimoto;H.Nakashima;M.Ishibashi;M.Mitsuhara et al.;光原昌寿 ら;M.Mitsuhara et al.;光原昌寿 ら
• 通讯作者: 光原昌寿 ら

Microstructural Analysis of Welded Joint in Crept 2.25Cr-1Mo Steels by EBSP Method

EBSP 法分析 2.25Cr-1Mo 蠕变钢焊接接头的显微组织

• 发表时间: 2004
• 期刊: Proc. of 8th Ultra-Steel Workshop
• 作者: M.Mitsuhara;D.Terada;H.Nakashima;周致霆 ら;M.Mitsuhara et al.;光原昌寿 ら;F.Yoshida et al.
• 通讯作者: F.Yoshida et al.