Microstructural modifications induced by hydrogen in a heat resistant steel type HP-45 with Nb and Ti additions

Ribeiro, A.F.; Almeida, Luiz Henrique de; Santos, D.S. dos; Fruchart, D.; Bobrovnitchii, G.S.

doi:10.1016/s0925-8388(03)00173-7

Cited by 17 publications

(4 citation statements)

References 11 publications

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“…It is in the healthy region of the tube which is the centre portion of the tube. The main damage mechanism for reformer tube is the combination of thermal stresses and internal pressure [9][10][11][12][13][14][15][16][17]. This combination of stresses causes creep damage that typically develops at the inner diameter or just below the internal diameter surface [6].…”

Section: Metallographymentioning

confidence: 99%

Remnant Life Assessment and Microstructural Studies on Service Exposed Primary Reformer Tubes of a Catalytic Converter of an Ammonia Plant

Gopal¹,

Swaminathan²,

Bagui³

et al. 2012

High Temperature Materials and Processes

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13.5 year service exposed (SE) catalyst primary reformer tube material made of H39WM micro-paralloy grade used in feritilizer plant was assessed for remaining life. The investigation includes mechanical properties evaluation; microstructural analysis and accelerated stress rupture tests. Failed tube portions showed coarsening primary carbides of Chromium and Niobium along the grain boundaries. Degradation of Niobium carbide (NbC) into Ni-Nb-Si phase and partial conversion this phase back to NbC was observed. Secondary carbides within grains were almost absent. Degradation in tensile strength for a range of temperature from 1123 to 1223 K was also observed but they were within the specified limits. Premature failures within 3-5 years service exposure are more common in reformer tubes. The failure was attributed to localized overheating leading to creep damage. The cast tube material may undergo microstructural changes during service exposure which is the main cause of degradation in strength and hardness changes. Accelerated stress rupture tests were performed in the range of 1173-1248 K on samples machined from 13.5 years at 1191 K and 15.4 MPa exposed reformer steel tubing, did not reveal any degradation of rupture behavior compared to that of the virgin alloy. An additional life of at least 10.6 years is predicted at the operating stress-temperature conditions.

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Section: Metallographymentioning

confidence: 99%

Remnant Life Assessment and Microstructural Studies on Service Exposed Primary Reformer Tubes of a Catalytic Converter of an Ammonia Plant

Gopal¹,

Swaminathan²,

Bagui³

et al. 2012

High Temperature Materials and Processes

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“…Large amounts of oxides were distributed at the grain boundaries of the original carbide-depleted region. According to Wagner's theory [ [17] , [18] , [19] , [20] , [21] ] and the oxide film rupture mechanism proposed by Evans [ 22 ], the nucleation of both Cr 2 O 3 and SiO 2 first occurred perpendicular to the metal matrix [ 23 , 24 ]. We divided the furnace tube tissue degradation process into five stages: (1) formation of the initial surface oxide layer, (2) oxidation of the carbon-containing atmosphere, (3) redistribution of Cr and C within the tubes, (4) internal carburization, and (5) oxidation of carbides.…”

Section: Resultsmentioning

confidence: 99%

Oxidation behavior and performance deterioration of cracking furnace tubes in service

Du,

Song,

et al. 2024

Heliyon

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“…Factors behind such variations are (i) burner regulation, (ii) loss in catalyst activity, (iii) aging of catalyst, (iv) collapse of catalyst column inside tube [34][35][36], (v) creep of tube material, (vi) thermal shock, (vii) overheating and (viii) carburization of inner wall. Therefore as designed life of 11.4 years or 100,000 hours appears to vary [37][38][39]. Failure investigation of HPmicroalloyed tube shows circumferential cracks on inner wall side.…”

Section: Fertilizer Industriesmentioning

confidence: 99%

Damage Analysis of Service Exposed Reformer Tubes in Petrochemical Industries

Raj

Goswami²,

Kumar³

et al. 2014

High Temperature Materials and Processes

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Accelerated creep or stress rupture data is used for remaining life assessment for life management studies of elevated temperature components, e.g. for reformer tubes where packed nickel catalysts are used for synthesis of hydrogen, ammonia etc. This research has become a regular task because of large range of time for failure (3 to 15 years) compared to designed life (11.4 years or 100,000 hours) and huge loss associated to damage, production and safety hazards. Utilization of appropriate inspection during plant shut down has been strategic short term life assessment. Tests have been typically done by high temperature mechanical properties, microstructure analysis and accelerated creep. Inspection of micro-cracks, hot spot formation, carburization/metal dusting for inner wall and oxidation, tube diameter increment for outer wall inspection have been traditional symptoms of expiry of tubes after service exposure. Aim of this review has been to study damage analysis of reformer tube in response to so wide time frame for failures and accidents involved, even after stipulation of designed time schedules.

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Microstructural modifications induced by hydrogen in a heat resistant steel type HP-45 with Nb and Ti additions

Cited by 17 publications

References 11 publications

Remnant Life Assessment and Microstructural Studies on Service Exposed Primary Reformer Tubes of a Catalytic Converter of an Ammonia Plant

Remnant Life Assessment and Microstructural Studies on Service Exposed Primary Reformer Tubes of a Catalytic Converter of an Ammonia Plant

Oxidation behavior and performance deterioration of cracking furnace tubes in service

Damage Analysis of Service Exposed Reformer Tubes in Petrochemical Industries

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