A Study on Material Degradation in Carbon Steel for Pressure Vessel at 179°C

2006 ◽  
Vol 321-323 ◽  
pp. 532-535
Author(s):  
Un Bong Baek ◽  
Jong Seo Park ◽  
Seung Hoon Nahm ◽  
Hyuck Mo Lee
Keyword(s):  
Carbon Steel ◽  
Room Temperature ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Life Assessment ◽  
Material Degradation ◽  
Ductile To Brittle Transition ◽  
Industrial Boilers ◽  
Micro Structures ◽  
Degradation Time

In spite of frequent defect in industrial boilers, life assessment or diagnostic method for them has not been studied. In this research, SB410 carbon steel used in industrial boilers is simulated with artificial aging heat treatment. To do qualitative life assessment, differences in micro-structures and hardness of SB410 by the degradation time are studied. In addition, variation in material properties by aging was observed with the tensile test at room temperature and 179 °C and changes in ductile to brittle transition temperature was observed with the charpy impact test performed at several test temperature.

Anisotropy of Mechanical Properties of API-X70 Spiral Welded Pipe Steels

2013 ◽  
Vol 753 ◽  
pp. 538-541 ◽  
Author(s):  
Haytham M. Al Jabr ◽  
John G. Speer ◽  
David K. Matlock ◽  
Peng Zhang ◽  
Sang Hyun Cho
Keyword(s):  
Rolling Direction ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Impact Testing ◽  
Granular Bainite ◽  
Secondary Phases ◽  
Pronounced Increase ◽  
Ductile To Brittle Transition ◽  
Welded Pipe ◽  
Anisotropy Of Mechanical Properties

The effects of microstructure and texture on the toughness anisotropy of two API-X70 pipeline steels were investigated. One steel contained no nickel (0Ni) and the other contained 0.3 wt pct nickel (0.3Ni). Charpy V-notch impact testing was conducted on plate samples for both steels in three directions: longitudinal (L), transverse (T), and diagonal (D) with respect to the rolling direction. The microstructures of both steels were mixed and consisted of acicular ferrite, granular bainite, and small amounts of polygonal ferrite, with martensite-austenite and retained austenite islands as secondary phases. The ductile to brittle transition temperatures (DBTT) for the Charpy impact test were higher in the D direction for both plates, with a pronounced increase in the 0Ni steel. The anisotropy in toughness was mainly attributed to the crystallographic texture.

Evaluation of Fracture Toughness From Instrumented Charpy Impact Tests for a Reactor Pressure Vessel Steel

2003 ◽  
Author(s):  
A. Parrot ◽  
P. Forget ◽  
A. Dahl
Keyword(s):  
Fracture Toughness ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Impact Tests ◽  
Reactor Pressure Vessel Steel ◽  
Ductile To Brittle Transition ◽  
Reactor Pressure

The monitoring of neutron induced embrittlement of nuclear power plants is provided using Charpy impact test in the surveillance program. However structural integrity assessments require the fracture toughness. Some empirical formulas have been developed but no direct relationship was found. The aim of our study is to determine the fracture toughness of a Reactor Pressure Vessel steel from instrumented Charpy impact test using local approach to fracture. This non-empirical method has been applied in the brittle domain as well as in the ductile to brittle transition for an A508 C1.3 steel. In the brittle domain, fracture occurs by cleavage and can be modeled with the Beremin model. Fracture toughness has been successfully determined from Charpy impact tests results and the influence of several parameters (mesh design, Beremin model with one or two parameters, number of Charpy impact tests results) on the results was considered. In the ductile to brittle transition, cleavage fracture is preceded by ductile crack growth. Ductile tearing has been accounted for in the simulations with the Rousselier model whereas cleavage fracture is still described with the Beremin model. The determination of fracture toughness from Charpy impact tests gave encouraging results but finite element simulations have to be refined in order to improve predictions.

Epoxy Adhesives Modified With Nano- and Microparticles for In Situ Timber Bonding: Fracture Toughness Characteristics

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Z. Ahmad ◽  
M. P. Ansell ◽  
D. Smedley
Keyword(s):  
Fracture Toughness ◽  
Room Temperature ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Single Edge ◽  
Notched Specimens ◽  
Epoxy Adhesives ◽  
Adhesive Formulation ◽  
Made In

Adhesives used for bonded-in steel or composite pultruded rods and plate to make connections in timber structures are commonly room temperature cure adhesives. The room temperature cure, applied without pressure, thixotropic, and shear thinning characteristics of the adhesives, is for ease of application when repairs and reinforcement are being made in situ in the field. The room temperature cure adhesive may not fully cross-link and this may cause brittleness. Therefore to improve the toughness properties of such adhesives, nanoparticles can be added. This paper reports the experimental investigation carried out on the fracture toughness of three thixotropic and room temperature cured epoxy-based adhesives formulated specifically for in situ timber bonding, namely, CB10TSS (standard adhesive), Albipox is CB10TSS with the addition of nanodispersed carboxyl-terminated butadiene acrylonitrile (CTBN), and Timberset is an adhesive formulation containing ceramic microparticles. The fracture toughness behavior of the adhesives was investigated using the Charpy impact test on unnotched and notched specimens conditioned at 20∘C/65%RH to evaluate notch sensitivity, and a single-edge notched beam (SENB) test was performed to evaluate the stress intensity factor KIC. The fracture surfaces were investigated using scanning electron microscopy. Under high impact rate, toughness was in the order of CB10TSS, Albipox, and Timberset. CB10TSS and Albipox were found to be ductile in the unnotched state and brittle when notched. Timberset was brittle in both unnotched and notched states. Under low strain rate (SENB) conditions the addition of CTBN significantly improved the fracture toughness of Albipox compared with CB10TSS and Timberset. Examination of the topography of the fractured surface revealed marked changes in crack propagation due to the addition of nano- or microfillers accounting for the variation in toughness properties.

scholarly journals Identification of ductile to brittle transition temperature by using plane strain specimen in tensile test and correlation with instrumented Charpy impact test: experimental and numerical study

2018 ◽  
Vol 19 (1) ◽  
pp. 107 ◽  
Author(s):  
Frank Tioguem ◽  
Matthieu Maziere ◽  
Franck Tankoua ◽  
André Galtier ◽  
Anne-Françoise Gourgues-Lorenzon
Keyword(s):  
Transition Temperature ◽  
Plane Strain ◽  
Numerical Study ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Charpy Impact Test ◽  
Fracture Mechanisms ◽  
Brittle Transition ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition

This study addresses the correlation between the ductile-to-brittle transition temperature ranges of high strength 4140 steel obtained respectively from tensile tests under plane strain (PS) conditions and from conventional Charpy impact tests. Specimens were taken respectively at 25 mm (P) and at 55 mm (M) from skin of a cylindrical 90-mm-radius hot rolled bar water quenched from 875 °C, tempered at 600 °C and air cooled. P and M samples respectively showed a fully martensitic and a martensite-bainite microstructure. Fracture surface observations showed good agreement for physical fracture mechanisms (cleavage facet size, mixed ductile + brittle fracture in the transition region, ductile fracture at higher temperatures) between PS and Charpy, in particular sensitivity of upper bainite to cleavage fracture that reduces fracture energy in the lower self-energy on Charpy tests.

Middle Shelf During Ductile to Brittle Transition on Ferrite + Pearlite Structure Steel Sheet

2018 ◽  
Vol 941 ◽  
pp. 453-457
Author(s):  
Hiroyuki Kawata ◽  
Osamu Umezawa
Keyword(s):  
Fracture Surface ◽  
Steel Sheet ◽  
Charpy Impact ◽  
High Strength ◽  
Charpy Impact Test ◽  
Propagation Path ◽  
Transition Curve ◽  
Brittle Transition ◽  
Ductile To Brittle Transition ◽  
Step Transition

The steels consisting of multi-phase structure show an advantage for their high strength and good formability. The ductile to brittle transition with decreasing temperature has been investigated by Charpy impact test with sub-size specimen for the ferrite + pearlite structure steel sheet. The transition curve of the absorbed energy showed a two-step transition behavior, and the “middle shelf” appeared clearly in the curve. The cleavage-like fracture with few dimples appeared on the fracture surface of the specimens at the middle shelf, and the plastic strain was detected just below the fracture surface. This result suggested that the fracture at the middle shelf propagates with the quasi-cleavage fracture accompanied with plastic deformation. Although the traces of fracture surface corresponded to (001), (011), and (112) bcc-iron planes, the (001) cleavage plane was not dominant for the fracture propagation path at the middle shelf.

Ductile-to-Brittle Transition Behavior of High-Nitrogen 18Cr-10Mn-0.35N Austenitic Steels Containing Ni and Cu

2010 ◽  
Vol 654-656 ◽  
pp. 158-161 ◽  
Author(s):  
Byoung Chul Hwang ◽  
Tae Ho Lee ◽  
Seong Jun Park ◽  
Chang Seok Oh ◽  
Sung Joon Kim
Keyword(s):  
Charpy Impact ◽  
Charpy Impact Test ◽  
Austenitic Steels ◽  
Favorable Effect ◽  
High Nitrogen ◽  
Delta Ferrite ◽  
Brittle Transition ◽  
Transition Behavior ◽  
Ductile To Brittle Transition ◽  
Crystallographic Planes

Ductile-to-brittle transition behavior of high-nitrogen 18Cr-10Mn-0.35N austenitic steels containing Ni and Cu was investigated by means of Charpy impact test and fractographic analysis. The commonly observed fracture mode of the specimens tested at -196 oC was transgranular cleavage-like brittle with flat facets occurring along {111} crystallographic planes, thereby leading to the occurrence of ductile-to-brittle transition. For all the steels investigated in the present study, the ductile-to-brittle transition temperature (DBTT) measured from Charpy impact tests was much higher by 90 to 135 oC than that predicted by empirical equation strongly depending on N content. The combined addition of Ni and Cu enabled the 18Cr-10Mn-0.35N steels to have the lowest DBTT, which could be explained by relatively high austenite stability and favorable effect of Cu as well as the absence of delta-ferrite.

scholarly journals Thermal Aging of Menzolit BMC 3100

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Pavol Kostial ◽  
Zora Kostialova Jancikova ◽  
Ondrej Krejcar ◽  
Kamil Kuca ◽  
Oluwaseun Fadeyi ◽  
...  
Keyword(s):  
Physical Properties ◽  
Thermal Aging ◽  
Room Temperature ◽  
Negative Impact ◽  
Charpy Impact ◽  
Thermomechanical Analysis ◽  
Material Degradation ◽  
Scanning Calorimetry ◽  
Shape Stability ◽  
Charpy Impact Strength

This paper deals with the influence of thermal aging on physical properties of a composite material, Menzolit BMC 3100. First, we present a number of analysis, FTIR (infrared spectroscopy), DSC (differential scanning calorimetry), TMA (thermomechanical analysis), TGA (thermogravimetric analysis), and HDT (heat deflection temperature), to understand the material performance under heat, and then, we carry out a test of toughness and strength using Charpy impact strength and Brinell hardness. Finally, we present optical surface analysis of the material under investigation by carrying out aging analysis at increments from room temperature up to 300°C. It was observed that above 200°C, the material begins to degrade at the surface, especially its organic component, polyester resin. This type of degradation has a negative impact on a variety of its physical properties. Exposure to temperatures above 200°C reduces the material’s hardness, toughness, and shape stability, likewise, material degradation was found to increase with higher thermal loads almost linearly for all the observed properties.

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