Prediction of the Remaining Life of High-Temperature/Pressure Reactors Made of Cr-Mo Steels

1985 ◽  
Vol 107 (3) ◽  
pp. 230-238 ◽  
Author(s):  
T. Iwadate ◽  
J. Watanabe ◽  
Y. Tanaka
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Prediction Model ◽  
Crack Growth ◽  
Life Prediction ◽  
Temper Embrittlement ◽  
Pressure Vessels ◽  
Remaining Life ◽  
Life Prediction Model

The Cr-Mo steels widely used for pressure vessels have a potential for temper embrittlement. Therefore, embrittlement during long-term service is expected, and it leads to the decrease of the critical flaw size of brittle fracture and/or to the reduction of the remaining life of a pressure vessel. In this paper, the concept of a remaining life prediction model is presented. And also, experimental data on the temper embrittlement and fracture toughness after long-term exposure and sub-critical crack growth rate, such as creep crack growth rate, were collected, and the data were analyzed for use in the remaining life prediction model. Examples of the remaining life prediction of a 2 1/4 Cr-1Mo steel hydrogenation reactor and a 1 1/4Cr-1/2Mo steel catalytic reforming reactor were calculated from the statistical data base.

Development and Validation of Load-Interaction Based Models for Crack Growth Prediction

2014 ◽  
Author(s):  
Jiaxi Zhao ◽  
Weixing Chen ◽  
Sean Keane ◽  
Jenny Been ◽  
Greg Van Boven
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Life Prediction ◽  
Pressure Fluctuations ◽  
Remaining Life ◽  
The Past ◽  
Oil Pipelines ◽  
Rainflow Counting ◽  
Development And Validation

This investigation primarily focused on the validation of the software being developed for crack growth and remaining life prediction using SCADA data. A total of nine pressure spectra, four for oil pipelines and five for gas pipelines, have been collected and used as inputs for the software. It was found that these spectra could be categorized as the underload-, the meanload- and the overload-dominant spectra; each of them have shown different effects on crack growth: the underload spectra, typical of pressure fluctuations at the discharging sites, are most susceptible to crack growth because of load interactions between the minor pressure fluctuations and the unload cycles; while the overload spectra, often found at the suction site, have exhibited retarded crack growth due to the retardation effects caused by overloading. The relative severity of the load interactions in terms of crack growth rate for a given spectrum was quantified using a parameter termed as the Spectrum Factor. A Spectrum Factor greater than one indicates the enhanced crack growth rate by load interactions, such as the case where unloading is frequently present in the pressure spectra, while a Spectrum Factor lower than one may be associated with a retarded crack growth, which can be seen in pressure spectra with predominant overloading events. The predictions made by the models being developed were also compared with those made by the rainflow counting method. The software allows for the SCADA/pressure fluctuation data, in excel spreadsheet format, to be directly analyzed producing a projected remaining life of the pipeline based on the past pressure fluctuations and the assumed future pressure fluctuations.

An Empirical Life Prediction Method of Cold-Stretched Austenitic Stainless Steel

2016 ◽  
Vol 853 ◽  
pp. 67-71
Author(s):  
Yu Han ◽  
Ke Sheng Wang
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Prediction Model ◽  
Test Data ◽  
Life Prediction ◽  
Pressure Vessels ◽  
Fatigue Life Prediction ◽  
Life Prediction Model

With the purpose of long-cycle safe operation of cold stretched austenitic stainless steel pressure vessels so as to achieve unification of economy and safety, prediction of fatigue life of S31603 austenitic stainless steel at high temperature is systematic studied. Based on the Hull-Rimmer cavity theory, a fatigue life prediction model applicable to stress controlled is developed. Fatigue test is carried out on the solution annealed and cold stretched S31603 steel at high temperature and corresponding test data is obtained. The fatigue life of the solution annealed and cold stretched materials is predicted by the model and the prediction results are in good agreement with the experimental results. On this basis, the life prediction model coupled with the strain level of cold stretching is further established. Compared with the test data, the prediction results is found to be very satisfactory with an error band less than ±1.5 times. The fatigue life prediction model suitable for stress control at high temperature is simple in form and has a clear and obvious physical significance which points out a new way to predict fatigue life of metal materials.

Remaining Life Prediction of Ethylene Cracking Tubes Under Carburizing and Creep Joint Action

2015 ◽  
Author(s):  
Luowei Cao ◽  
Chenyang Du ◽  
Shanshan Shao ◽  
Guoshan Xie
Keyword(s):  
Prediction Model ◽  
Oxide Layer ◽  
Transition Layer ◽  
Life Prediction ◽  
Rupture Life ◽  
Base Material ◽  
Stress Rupture ◽  
Remaining Life ◽  
Carburized Layer ◽  
Life Prediction Model

Remaining life prediction model of ethylene cracking tubes (ECT) suffered joint damage of carburizing and creep have been set up in this study. Materials employed in this work were cut from Cr35Ni45-type radiation section of ECT. Layered structure, including oxide layer, carburized layer and carburizing transition layer, have been found from inside to outside of the tubes in scanning electron microscopy (SEM) images. However, no abrupt transition occurs between carburized layer and the base material. Both carburizing related layers caused the damage of the tubes, together with oxide layer. In order to facilitate the life prediction accuracy, carburizing transition layer was considered as a part of the damage layer. The remaining life of ECT was investigated by review of the microstructure and stress-rupture tests. Stress-rupture tests have been finished to obtained the rupture life of the tubes at 1000°C, 1040°C, 1080°C and 1125°C under six loading stresses (10MPa, 15MPa, 17MPa, 20MPa, 25MPa and 30MPa, respectively). In the results of stress-rupture tests, the combination of testing temperature at 1040°C and loading stress with 15MPa got the highest rupture life of 830h. Finally, a modified Larson-Miller remaining life prediction model of ECT, considering the comprehensive effect of carburizing and creep damage, has been established.

Sign in / Sign up

Export Citation Format

Share Document