scholarly journals Fractographic Analysis Of Selected Boron Steels Subjected To Impact Testing

2015 ◽  
Vol 60 (3) ◽  
pp. 2373-2378 ◽  
Author(s):  
W. Dudziński ◽  
Ł. Konat ◽  
B. Białobrzeska
Keyword(s):  
Transition Temperature ◽  
Impact Testing ◽  
Transition Curve ◽  
Brittle Transition ◽  
Significant Difference ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition ◽  
Character Of Fracture ◽  
The Impact ◽  
Boron Steels

Abstract In this paper dynamic properties of low-alloy boron steels – Hardox 500, B27 and HTK 900H in delivered state (after hardening and tempering) are considered. Charpy V-notch (CVN) test results in connection with fractography in the ductile-to-brittle transition temperature region were analyzed. Obtained from CVN test the impact transition curve, not always predicts properly a behavior of materials in conditions of dynamic loading. So an analyze of character of fracture helps to evaluate the real behavior of materials. Tested samples were cut out longitudinally in relation to cold work direction. The results of CVN test for selected steels, in temperatures: −40°C, −20°C, 0°C and +20°C are presented. Regarding ductile-to-brittle transition temperature, there is a significant difference taking into account values of Charpy V energy absorbed and a character of fracture.

scholarly journals A Study of Fracture Mechanisms in RAFM Steel in the Ductile to Brittle Transition Temperature Regime

2014 ◽  
Vol 86 ◽  
pp. 258-263 ◽  
Author(s):  
A. Moitra ◽  
Arup Dasgupta ◽  
S. Sathyanarayanan ◽  
G. Sasikala ◽  
S.K. Albert ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Temperature Regime ◽  
Fracture Mechanisms ◽  
Brittle Transition ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition ◽  
Rafm Steel

scholarly journals EXPERIMENTAL INVESTIGATION OF THE FAILURE BEHAVIOUR OF POLYPROPYLENE COMPOUNDS FOR INSTRUMENTED PUNCTURE TESTS

2018 ◽  
Vol 18 ◽  
pp. 66
Author(s):  
Florian Kiehas ◽  
Anna Kalteis ◽  
Michael Jerabek ◽  
Zoltán Major
Keyword(s):  
Experimental Investigation ◽  
Transition Temperature ◽  
Glass Fibre ◽  
Failure Behaviour ◽  
Brittle Transition ◽  
Ductile Brittle Transition Temperature ◽  
Determination Methods ◽  
Brittle Transition Temperature ◽  
The Impact

Instrumented puncture tests according to ISO 6603-2 and ASTMD3763 were executed for five different Polypropylene compounds (talcum-, glass fibre- and elastomer modified) with specimen thicknesses ranging from 1mm to 4 mm. Over 1500 puncture tests were executed at the Impact & Long-term Behaviour laboratory of the company Borealisr in Linz. This serves as strong foundation for statistical evaluations of the ductile/brittle transition temperature. For different materials and ductile/brittle transition determination methods, similar trends have been observed, which were characterized by introducing shift factors.

Study on Ductile Brittle Transition Temperature of Q345C Steel MAG Welded Joints

2016 ◽  
Vol 703 ◽  
pp. 155-159
Author(s):  
Yong Shou Wu ◽  
Yong Jun Liu
Keyword(s):  
Transition Temperature ◽  
Low Temperature ◽  
Weld Seam ◽  
Brittle Transition ◽  
Absorption Energy ◽  
Ductile Brittle Transition Temperature ◽  
Brittle Transition Temperature ◽  
Impact Absorption Energy ◽  
The Impact ◽  
Impact Absorption

For Q345C steel MAG welded joints, low temperature tensile test was carried out at normal atmospheric temperature, 0°C,-20°C,-30°C and-40°C in the paper, which results in the law of strength change with temperature. The impact absorption energy of the weld seam sample under different temperature conditions was tested, impact fracture morphology was observed and the parentage of the fibrous fracture surface was assessed. The curve of impact absorption energy and the percentage of the fibrous fracture surface with temperature were fitted by using the Boltzmann function, and ductile brittle transition temperature of Q345C steel MAG welded joints was determined. The test results show that the impact absorption energy of the weld seam can reach 71J at-40°C, and the weld seam is prone to brittle fracture under low temperature. The influences of alloying elements and microstructure on the ductile brittle transition temperature and low temperature impact toughness were discussed, and suggestion is put forward to improve the impact toughness and reduce the ductile brittle transition temperature.

Variables Affecting Fracture Toughness of Welds in T-K-Y Connections

2014 ◽  
Author(s):  
Radhika Panday ◽  
Shenjia Zhang ◽  
Jon Ogborn ◽  
Badri K. Narayanan
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Transition Temperature ◽  
Weld Metal ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Factors Affecting ◽  
Brittle Transition ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition

Fracture toughness of tubular welded joints is one of the critical factors affecting the structural integrity and reliability of offshore structures, such as platforms and subsea pipelines. The factors affecting the design fracture toughness of these structures are related to, both, the welding process as well as the chemical composition of the weld metal. The welding process in this application typically comprises of depositing weld metal in the tubular joints of varying thicknesses through series of weld passes. The number of weld passes required for welding these joints subjects the weld metal to repetitive cycles of heating and cooling. The effect of the thermal cycling introduces significant heterogeneity in the microstructure. This is further exacerbated by the presence of micro-alloying elements such as Niobium (Nb) and Vanadium (V) that form complex carbides, nitrides and carbo-nitrides during post weld heat treatment (PWHT). The focus of this work is to evaluate the effect of micro-alloying elements on the ductile to brittle transition temperature and the mode of fracture at temperatures relevant to offshore applications. A threshold Nb and V level has been determined for achieving acceptable weld metal toughness. The improvement in the fracture toughness using this approach has been quantified by Charpy V-Notch (CVN) and Crack Tip Opening Displacement (CTOD) measurements. The Ductile to Brittle Transition Temperature (DBTT) has been shown to be shifted to lower temperatures by 25 °C after post weld heat treatment in the welds where the total amount of Nb and V are controlled to less than 40 ppm. A wet precipitate extraction technique was used to extract precipitates from the welds to establish the presence of fine Nb rich precipitates in the welds with the higher DBTT. The weld deposited with controlled levels of Nb and V was further tested in different joint configurations and base plate thickness. The fracture toughness was evaluated by CTOD testing of the weld in two different thicknesses (50 mm and 70 mm). Increased specimen thickness resulted in lower CTOD values.

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