کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5013742 | 1462957 | 2016 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Fatigue propagation of short and long cracks in gaseous hydrogen environment in 3.5NiCrMoV steel
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی صنعتی و تولید
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Fatigue propagation of short and long cracks in gaseous hydrogen environment in 3.5NiCrMoV steel Fatigue propagation of short and long cracks in gaseous hydrogen environment in 3.5NiCrMoV steel](/preview/png/5013742.png)
چکیده انگلیسی
Turbo generators for nuclear plants are mostly equipped with hydrogen cooling systems. Current practice of characterizing the growth of fatigue cracks on the basis of fracture mechanics primarily relies on fatigue tests for long cracks which are typically of several millimeters in length. However, in view of extended life for the plants, the damage tolerance evaluation of such fatigue-critical engineering components requires understanding of the propagation of cracks of significantly smaller dimensions. Then the near threshold of short cracks is investigated and compared to the behavior of long crack by experiments under 4 bar hydrogen atmosphere. The short crack fatigue propagation in hydrogen atmosphere is shown similar to that in air, growing faster than the long crack and at ÎK ranging below the long crack threshold; this effect is related to a reduced crack closure shielding. The propagation behavior of long crack under hydrogen atmosphere is shown similar to that obtained in air in the low rate range, i.e. when the maximum of the stress intensity factor Kmax is lower than a critical level of about 16 MPa m1/2 with higher crack growth rate than in high vacuum. This environment effect is related to the presence of residual water vapor in both gases. For higher Kmax, much faster growth rates under hydrogen atmosphere in comparison to air and vacuum are observed and related to hydrogen assisted intergranular propagation combining fatigue and sustained loading damage. The results are discussed on the basis of micrographic observations supporting the involved mechanisms.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Engineering Failure Analysis - Volume 69, November 2016, Pages 29-34
Journal: Engineering Failure Analysis - Volume 69, November 2016, Pages 29-34
نویسندگان
Christine Sarrazin-Baudoux, Catherine Gardin, Gaëlle Chrétien, Tuan-Hiep Pham, Guillaume Benoit, Van-Xuan Tran, Jean Petit,