A metallographic study of aging in a cast heat-resisting alloy

Rodríguez, José Juan Santana; Haro, Sergio; Velasco, Abraham; Colás, Rafael

doi:10.1016/s1044-5803(00)00047-4

Cited by 49 publications

(16 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The microstructure consists of large primary dendrites, separated by narrow interdendritic zones containing primary eutectic carbides, formed at the end of solidification. 3,12,13 The dendrites contain a fine dispersion of secondary carbides formed during the aging treatment. The significant creep resistance of these steels is mainly related to the extensive carbide precipitation.…”

Section: Introductionmentioning

confidence: 99%

Method for predicting risk of cracking during weld repair of heat resistant cast steels

Duchosal¹,

Deschaux-Beaume²,

Bordreuil³

et al. 2008

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

Owing to their low ductility at room temperature, heat resistant cast austenitic stainless steels are very sensitive to weld cracking. Cracks are formed in brittle zones of the heterogeneous microstructure constituted by the carbide rich interdendritic spaces. In order to identify the operating factors affecting the cracking propensity of such steels during welding, a three step method, based on numerical simulation, is presented. First, the macroscopic temperature and stress fields are determined by a finite element calculation, considering a homogeneous material. In a second step, a localisation criterion is defined to identify critical zones, according to the macroscopic fields determined in the first step. Then, the heterogeneous microstructure of the cast steel is modelled in a 'representative cell', and the thermomechanical history of the critical zone previously identified is applied as boundary condition, in order to determine the local stress field. The cracking is then supposed to occur when the maximal principal stress in the interdendritic zone of the representative cell reaches the cleavage stress of the carbides, determined using SEM in situ tensile tests. This method is used to predict cracking during multipass weld repair of bulk samples, under various welding conditions. A comparison is carried out between experiment and simulation to validate the method.

show abstract

Section: Introductionmentioning

confidence: 99%

Method for predicting risk of cracking during weld repair of heat resistant cast steels

Duchosal¹,

Deschaux-Beaume²,

Bordreuil³

et al. 2008

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

show abstract

“…HAZ regions are zones of preference for longitudinal cracks. Annealing to re-weld and rejuvenate the old tubes are more detrimental to the cavities than morphological variation in carbide from heat-treatment effects compared to prior existing carbides [40][41][42].…”

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

View full text Add to dashboard Cite

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.

show abstract

“…This stabilization treatment promotes the carbide precipitation issued from supersaturated elemental carbon remained in excess in the solid solution. These secondary carbides are too small to be analysed by EDS, but literature generally considers there are chromium carbides [1,11,15].…”

Section: Microstructurementioning

confidence: 99%

Analysis of weld-cracking and improvement of the weld-repair process of superplastic forming tools

Duchosal

Deschaux-Beaume

Lours

et al. 2013

Materials & Design (1980-2015)

View full text Add to dashboard Cite

of weld-cracking and improvement of the weld-repair process of superplastic forming tools. Materials and Design, Elsevier, 2013, 46, pp.731-739. 10.1016/j.matdes.2012 AbstractSuperplastic forming (SPF) dies are generally made of using heat resistant cast steels, which are very sensitive to weld cracking. In order to improve the weld-repair process of such dies to prevent weld-cracking, the microstructure and the mechanical behaviour of a typical heatresistant cast steel was first studied, using isothermal low-cycle fatigue tests and in-situ tensile tests. The welding behaviour of such steel was also investigated, using a shielded metal arc welding (SMAW) process and welding conditions similar to those employed for weld repair industrial dies. The comparison of the aspect of weld-cracking with the fracture mechanisms observed at room temperature or during isothermal low-cycle fatigue tests suggests a similar brittle failure mechanism, due to the presence of large interdendritic carbides in the cast steel.The melting of the cast steel surface using a gas tungsten arc welding (GTAW) process allowed to refine the primary carbides, and then to reduce the weld-cracking sensitivity. The 2 refining method with GTAW before welding has been successfully tested to weld-repair a sample representative of SPF dies, and is recommended for subsequent repairs of such dies.

show abstract

A metallographic study of aging in a cast heat-resisting alloy

Cited by 49 publications

References 5 publications

Method for predicting risk of cracking during weld repair of heat resistant cast steels

Method for predicting risk of cracking during weld repair of heat resistant cast steels

Damage Analysis of Service Exposed Reformer Tubes in Petrochemical Industries

Analysis of weld-cracking and improvement of the weld-repair process of superplastic forming tools

Contact Info

Product

Resources

About