Warm-Forging Characteristics and Microstructural Response of Medium-Carbon High-Strength Steels for High-Duty Components

2014 ◽  
Vol 611-612 ◽  
pp. 167-172 ◽  
Author(s):  
Piotr Skubisz ◽  
Łukasz Lisiecki
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Microstructure Evolution ◽  
High Strain ◽  
Deformation Behaviour ◽  
Metal Flow ◽  
High Strength Steels ◽  
High Strength ◽  
Medium Carbon ◽  
Warm Forging

Paper presents deformation behaviour and microstructural response of selected medium-carbon high-strength steels commonly used for high-duty components deformed under high-strain-rate and warm work temperature range. The investigation of material behaviour is oriented at analysis of hot and warm workability of material and microstructure evolution resultant from deformation mechanisms, strain induced recrystallization and hardening at temperatures of lower forging regime and high strain rate deformation. The effect of these factors on microstructure after forging and subsequent direct-cooling was studied. Metallographic work aided with numerical methods of simulation of the metal flow and microstructure evolution during forging were used to correlate thermo-mechanical parameters observed with microstructure and mechanical properties after forging and cooling.

scholarly journals Modern high strength steels under high strain-rate regimes

2021 ◽  
Vol 250 ◽  
pp. 05013
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Single Layer ◽  
High Strength Steels ◽  
High Strength ◽  
Critical Infrastructures ◽  
Mechanical Resistance ◽  
Large Specimen ◽  
High Rise

In order to properly design critical infrastructures and buildings in steel (bridges, high-rise building, off-shore, cranes, etc.), certain requirements concerning to mechanical resistance and robustness under exceptional actions have to be carefully fulfilled. An acceptable level of safety must be assured to avoid human loss, environmental pollution and material damage. These structures can be subjected to severe accidental loading such as blast or impact. In this context it is fundamental to adequately know the behaviour of structural steel under high strain rate. Modern high strength steels are quenched and selftempered steels. These steels have several layers with differentiated microstructures (martensitic in the cortical part and ferritic in the core). The behaviour of the single layer at high strain rate regimes have to be accurately studied. The paper collects and discusses the tensile results at high strain rate obtained on samples of homogeneous layers of S690QL and S960QL steels. Finally, the characterisation of the single layers has been used in order to analyse the results obtained in large specimen obtained from slabs 12mm thick.

Influence of the contact with friction on the deformation behavior of advanced high strength steels in the Nakajima test

2021 ◽  
pp. 030932472110212
Author(s):  
Mohammad Mehdi Kasaei ◽  
Marta C Oliveira
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Rate ◽  
Contact Pressure ◽  
Deformation Behaviour ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels ◽  
Deformation Mechanics ◽  
Nakajima Test

This work presents a new understanding on the deformation mechanics involved in the Nakajima test, which is commonly used to determine the forming limit curve of sheet metals, and is focused on the interaction between the friction conditions and the deformation behaviour of a dual phase steel. The methodology is based on the finite element analysis of the Nakajima test, considering different values of the classic Coulomb friction coefficient, including a pressure-dependent model. The validity of the finite element model is examined through a comparison with experimental data. The results show that friction affects the location and strain path of the necking point by changing the strain rate distribution in the specimen. The strain localization alters the contact status from slip to stick at a portion of the contact area from the pole to the necking zone. This leads to the sharp increase of the strain rate at the necking point, as the punch rises further. The influence of the pressure-dependent friction coefficient on the deformation behaviour is very small, due to the uniform distribution of the contact pressure in the Nakajima test. Moreover, the low contact pressure range attained cannot properly replicate real contact condition in sheet metal forming processes of advanced high strength steels.

Tension and Compression Behavior of Pre-Stressed Steel Strands at High Strain Rate

2011 ◽  
Vol 82 ◽  
pp. 154-159 ◽  
Author(s):  
Anatoly M. Bragov ◽  
Ezio Cadoni ◽  
Alexandr Yu. Konstantinov ◽  
Andrey K. Lomunov
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
High Strength ◽  
Gauge Length ◽  
Hopkinson Pressure Bar ◽  
Dog Bone ◽  
Tension And Compression ◽  
Set Up

In this paper is described the mechanical characterization at high strain rate of the high strength steel usually adopted for strands. The experimental set-up used for high strain rates testing: in tension and compression was the Split Hopkinson Pressure Bar installed in the Laboratory of Dynamic Investigation of Materials in Nizhny Novgorod. The high strain rate data in tension was obtained with dog-bone shaped specimens of 3mm in diameter and 5mm of gauge length. The specimens were screwed between incident and transmitter bars. The specimens used in compression was a cylinder of 3mm in diameter and 5mm in length. The enhancement of the mechanical properties is quite limited compared the usual reinforcing steels.

Sign in / Sign up

Export Citation Format

Share Document