Microstructural Evolution and Change in Hardness of S30432 Heat‐resistant Steel during Creep at 650 °C

Zhu, Lihui; Zhang, Y.J.; Wang, Q.J.; Xu, Song

doi:10.1002/srin.200900111

Cited by 6 publications

(9 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Different from plastic deformation process that occurred at room-temperature or low-temperature conditions, deformation process under high-temperature conditions can induce a time-dependent diffusion process and microstructure evolution, which leads to a unique deformation mechanism that is referred as creep. [1][2][3] To meet the requirements of materials that have been used on power plants and high-temperature pressure vessels, a series of heat-resistant steels are developed to improve the high-temperature mechanical performance. [4] As the failure of structural components used under high-temperature conditions generally leads to fatal safety accident, creep life of the heatresistant steels needs to be predicted as precise as possible.…”

Section: Introductionmentioning

confidence: 99%

“…[4,12,13] On the contrary, phenomenological mathematical methods are widely used in practical production due to their high efficiency and acceptable accuracy. [3,14] In addition, the θ projection method is further developed in the past few decades, and several modified forms are proposed to improve the prediction accuracy. [9,15,16] However, to select the appropriate method, the difference between the classical 4-parameter method and its modified forms needs to be comparatively studied.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparative Study of θ Projection Method and Its Modified Forms on Creep Life Prediction

Cheng

Guo

et al. 2023

steel research int.

View full text Add to dashboard Cite

The phenomenological characteristics of θ projection method constrain its prediction accuracy, especially at the primary creep stage. Herein, the mathematical features of the classical θ projection method and its modified forms based on a group of creep curves of a newly designed low‐cost heat‐resistant steel are analyzed. A detailed data processing method is introduced, and the prediction accuracy is comparatively studied with respect to the relative error on different creep stages. Results reveal that the simplified 3‐parameter method brings a balanced improvement on the residual errors by sacrificing the prediction accuracy on primary creep. However, the 5‐parameter method can precisely predict the characteristics of primary creep, and the tolerance fitting process can further reduce the deviation at the tertiary creep stage. Furthermore, the 5‐parameter method shows a larger reliable prediction region than the 3‐parameter method, and the two methods present good consistency when the applied stress is larger than 134 MPa. Herein, theoretical guidance for the selection of different θ projection methods is provided.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparative Study of θ Projection Method and Its Modified Forms on Creep Life Prediction

Cheng

Guo

et al. 2023

steel research int.

View full text Add to dashboard Cite

show abstract

“…The addition of Nb strengthens the steel through precipitation strengthening as it forms Nb(C,N) [2]. Cu rich nano-precipitates that form during service also provide precipitation strengthening [3,4,5]. In stainless steels the addition of N improves the creep strength through solid-solution strengthening however, for Super 304H the concentration of N is optimised to be below 0.12 wt% to minimise the ductility loss after longterm aging at service temperature [2].…”

Section: Introductionmentioning

confidence: 99%

“…The combination of both Nb and N can cause the precipitation of fine NbCrN complex nitrides [6][7][8][9] which could contribute as an effective precipitation strengthener in Super 304H steel during creep [2,9]. Other phases that have been identified in Super 304H that have been in service or during creep testing are sigma [6][7][8][9][10][11][12], M23C6 [5][6][7][8][9][10][11][12][13][14] and (Cr, V)2 N [15].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructural characterisation of creep tested advanced austenitic stainless steel super 304H

Pulsford

Jepson

Thomson

et al. 2022

Materials at High Temperatures

View full text Add to dashboard Cite

Super 304H is an advanced austenitic stainless steel that is used as superheater and reheater tubes in power plants. The presence of second phases such as MX particles, M23C6, Cu particles and sigma phase that evolve during creep testing and during service expose can have an impact on the creep rupture properties and lifetime of these components manufactured from Super 304H. In this research, the phases present in the gauge section of two creep rupture samples of Super 304H that had been exposed to a uniaxial creep test at temperatures of 650°C (Sample B) and 700°C (Sample A) and stresses of 120MPa and 75MPa respectively, have been identified and quantified. These two creep samples had exhibited low creep ductility. Within the two creep samples, six phases have been identified: MX (Nb rich), sigma, Cu rich, M23C6 (Cr rich), modified Z phase and Fe (BCC). Quantification of Nb rich and Cu rich particles revealed approximately 10% more Nb rich and 16% more Cu rich particles in Sample A compared to Sample B. Furthermore, the average particle size measured in Samples A and B are similar for both the Nb and Cu rich particles. This shows that differing temperatures and stresses of the two creep tests did not have a significant impact on the presence, number or size of Nb and Cu rich particles in these samples. The amount of sigma phase measured in Sample A and Sample B was similar and lower than that predicted by thermodynamic calculations. However, there appears to be an association between the sigma phase and creep cavities as shown in 2D microstructural characterisation. The association of sigma and creep cavities could have contributed to the low creep ductility exhibited by these two creep samples.

show abstract

Research on Microstructure and Mechanical Property of S30432 Supreheater Pipe Aged at 700°C

Liang

Zhao

et al. 2012

steel research int.

View full text Add to dashboard Cite

The microstructure and performance of S30432 supreheater pipe were investigated before and after it is aged 3000 h at 700°C. A lot of twins disappeared after aging, M23C6 particles precipitated along the grain boundary and MX particles precipitated near the dislocation. After the endurance experiment of the aged pipe, M23C6 precipitations with the size of about 50 nm pinned dislocations and the cavity appeared on the grain boundary. The aged S30432 supreheater pipe showed the ductile fracture. Increasing temperature made the inter‐granular fracture transfer the quasi‐cleavage fracture and the equiaxed morphology change the parabola morphology. The strength of the untreated specimen decreased with the temperature increasing. The hardness and the impact energy of the aged specimen were larger than those of the untreated specimen. Tensile strength and elongation of untreated specimen were larger than that of aged specimen.

show abstract

Microstructural Evolution and Change in Hardness of S30432 Heat‐resistant Steel during Creep at 650 °C

Cited by 6 publications

References 7 publications

Comparative Study of θ Projection Method and Its Modified Forms on Creep Life Prediction

Comparative Study of θ Projection Method and Its Modified Forms on Creep Life Prediction

Microstructural characterisation of creep tested advanced austenitic stainless steel super 304H

Research on Microstructure and Mechanical Property of S30432 Supreheater Pipe Aged at 700°C

Contact Info

Product

Resources

About