scholarly journals PROTECTIVE EFFECTIVENESS OF ARMOUR MADE OF NANOBAINITIC STEEL

2020 ◽  
Vol 72 (1) ◽  
pp. 21-38
Keyword(s):  
Heat Treatment ◽  
Plate Thickness ◽  
Steel Plates ◽  
Test Results ◽  
Controlled Cooling ◽  
Protective Capacity ◽  
Limit Values ◽  
Static Tensile ◽  
Firing Tests ◽  
Protective Effectiveness

The article presents the results of tests on resistance to perforation of nanobainitic steel plates with a thickness in the range of 6–9 mm with the use of projectiles with different perforation mechanisms. Firing tests were carried out using 7.62×39 mm BZ ammunition in accordance with the requirements of the NATO Stanag 4569A standard document (level 2) and 7.62×54R mm B32 ammunition to determine the V50 parameter for selected variants and plate thickness. The plates constituting the testing material were manufactured on an industrial scale from two heats with different chemical composition. The nanobainitic steel plates were subjected to heat treatment including austenitisation, controlled cooling and direct isothermal annealing, the parameters of which were optimised in order to achieve the highest protective capacity. Microstructure studies were carried out in places where the projectile and the plate interacted, in order to analyse the effects of firing in detail. The obtained test results indicated limit values of projectile velocities and plate thicknesses for which ballistic protection is effective. The range of mechanical properties determined in a static tensile test as well as the type of microstructure were determined, including the content and form of retained austenite, guaranteeing compliance with the required level of resistance to perforation. Based on the results of the firing tests, heat treatment variants were selected for plates of a certain thickness intended for the armour of an observation and protective container. The studies and tests were carried out as part of the POIR 04.01.04-00-0047/16 project, the main goal of which is to reduce the weight of a LOOK container armour.

Cutting of a Longitudinally Stiffened Plate by a Wedge

1994 ◽  
Vol 38 (04) ◽  
pp. 340-348 ◽  
Author(s):  
Jeom Kee Paik
Keyword(s):  
Plate Thickness ◽  
Wedge Angle ◽  
Steel Plates ◽  
Test Results ◽  
Stiffened Plate ◽  
Absorbed Energy ◽  
Dimensionless Analysis ◽  
Cutting Length ◽  
Plate Aspect Ratio ◽  
Stiffened Steel

The aim of this study is to obtain test data for longitudinally stiffened steel plates which are quasistatically cut by a rigid wedge, idealizing the deck or bottom platings in ship collision or grounding, and also to derive an empirical formula relating the absorbed energy and cutting length. A series of tests for longitudinally stiffened high-tensile steel plates is conducted, varying several factors, namely plate thickness, plate aspect ratio, angle/shape of wedge tip and property of stiffeners. A total of 50 specimens with thicknesses in the range of 3.4 to 7.8 mm and wedge angles of 15, 30, 45, and 60 deg, including one unstiffened and two horizontally stiffened plate specimens, were tested. The importance of each parameter and its effect on the cutting response are investigated. By dimensionless analysis of the test results obtained here, the energy absorbed while a longitudinally stiffened plate is cut by a wedge is expressed as a function of cutting length, yield stress, equivalent plate thickness, and wedge angle. Incorporation of dynamic effects into the static formula is suggested. A comparison of the proposed solutions with the previous formulas or drop-hammer test results is made.

scholarly journals Effect of heat treatment on the tensile properties of incrementally processed modified polylactide

Polimery ◽  
2021 ◽  
Vol 66 (6) ◽  
pp. 357-361
Author(s):  
Bogdan Kozik ◽  
Mariusz Dębski ◽  
Piotr Bąk ◽  
Małgorzata Gontarz ◽  
Małgorzata Zaborniak
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Testing Machine ◽  
Strength Properties ◽  
Annealing Process ◽  
3D Printer ◽  
Test Results ◽  
Heat Treated ◽  
Strength Tests ◽  
Static Tensile

The article presents the results of strength tests in the form of a static tensile test on the INSTRON 5967 testing machine. Samples were made with the use of the Prusa i3 MK3 3D printer, by modeling with a plasticized material (FFF) made of ABS copolymer, polylactide and its modified variant. According to the information provided by the manufacturer, heat-treated modified polylactide has mechanical properties similar to ABS copolymer filament. The publication also discusses the method of manufacturing elements subjected to the tests, the heat treatment process, as well as changes in material properties as a result of this treatment. Based on the test results, it was found that the annealing process increased the proportion of the crystalline phase, which significantly improved the strength properties of the modified polylactide.

OPTIMISATION OF BALLISTIC PROPERTIES OF NANOSTRUCTURED BAINITIC STEEL PLATES FOR CONTAINER ARMOUR SYSTEM

2020 ◽  
Vol 151 (3) ◽  
pp. 97-119
Author(s):  
Jarosław Marcisz ◽  
Bogdan Garbarz ◽  
Władysław Zalecki ◽  
Zofia Kania-Pifczyk ◽  
Lech Starczewski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Chemical Composition ◽  
Steel Plates ◽  
Industrial Scale ◽  
Bainitic Steel ◽  
Sensitive Areas ◽  
Ballistic Protection ◽  
Bainite Steel ◽  
Firing Tests

Abstract: An innovative armour system containing plates made of nanostructured bainite steel is under development to improve operating properties of a light armoured observation-protective container (LAOC) providing the 2nd protection level according to STANAG 4569. Armour system solution of the container has been modified because the new plates have different mechanical and technological properties than currently used armour plates. The paper presents results of investigation of material characteristics and firing tests of plates made of nanostructured steel in the semi-industrial scale. To optimise parameters of heat treatment of the plates the kinetics of phase transformation was examined, and mechanical properties were measured, and changes in microstructure in the area of projectile interaction at firing tests were analysed for different variants of treatment. The reported investigations precede the industrial scale production process for plates made of the new grade steel designed for the armour system of LAOC. Optimisation of mechanical properties of the plates has been carried out by selection of such production parameters as chemical composition of the steel, hot working, interprocess heat treatment and temperature and time of final heat treatment (isothermal annealing). Effect of primary segregation of alloying and residual elements on protective properties of the plates is indicated. As a result of applying the annealing temperature in the range of 210-225°C (Ms temperature is ca. 200°C at cooling rate 1-2°C/s) and time in the range of 120-70 hours respectively, the following properties have been achieved: YS0.2 (yield strength) 1400-1500 MPa; UTS (ultimate tensile strength) 2000-2150 MPa; TE (total elongation) 10-13%, impact toughness KV at room temperature 10-16 J and hardness 590-610 HV (53-54 HRC). Microstructure of the plates consists of carbide free lathy nanobainite and 10-21% (volume fraction) of retained austenite. Plates of thickness 6.3 and 7.5 mm and ammunition type of 5.56x45 mm M193 and 7.62x51 mm API BZ have been used in the firing tests. Based on results of firing tests and microstructure examination in the area of projectile interaction the phenomena have been identified indicating high efficiency of ballistic protection of investigated plates, manifested by high ability to absorption and dissipation of projectile energy without susceptibility to cracking. Based on the results of mechanical properties measurements and firing tests a chemical composition of the nanostructured bainitic steel adjusted for industrial production of plates of thickness in the range of 6-8 mm has been developed. An analysis of container armour system mass reduction possibility, basing on results of investigation of the nano-structured bainite steel plates made in the semi-industrial scale, has been carried out. Basing on the analysis of the container construction and operational conditions some sensitive areas of ballistic protection have been specified to be subjected to firing tests. Ballistic examination will be carried out using the container segments representing the selected sensitive areas.

scholarly journals Investigation of Uncertain Factors on Measuring Residual Stress with Critically Refracted Longitudinal Waves

2019 ◽  
Vol 9 (3) ◽  
pp. 485 ◽  
Author(s):  
Shunmin Yang ◽  
Mingquan Wang ◽  
Lu Yang
Keyword(s):  
Residual Stress ◽  
Stress Measurement ◽  
Plate Thickness ◽  
Longitudinal Mode ◽  
Steel Plates ◽  
304 Stainless Steel ◽  
Test Results ◽  
X Ray Diffraction ◽  
Transducer Signal ◽  
Measurement Approach

Critically refracted longitudinal (LCR) waves are commonly used to evaluate the residual stress of a material. The utilization of LCR waves is advantageous in that these waves are not sensitive to the texture of the material. Thus, LCR can be considered as a bulk longitudinal mode and can penetrate into the material well below its surface. However, while measuring the residual stress, the precision of the LCR wave travel-time is influenced by several uncertain factors. In order to further improve the accuracy of test results, we developed a measurement approach based on three aspects. First, the distances between the transmitter and the receivers were determined by transducer signal analysis. Second, for the residual stress detection to be consistent, transducers with different frequencies presented similar beam divergence angles. Finally, three different frequencies were used to evaluate the residual stress throughout the plate thickness. Based on the results of the above analysis, we used LCR waves to test 304 stainless steel plates. The detection error of residual stress measurement was ca. ±23 MPa. When compared with the X-ray diffraction approach, our method showed similar trends for the same regions of the specimens.

scholarly journals The Effect Of Heating Temperature On The Hardness, Microstructure And V-Bending Spring Back Results On Commercial Steel Plate

2019 ◽  
Vol 1 (1) ◽  
pp. 1-16
Author(s):  
Asep Ruchiyat ◽  
Muh Anhar ◽  
Yusuf Yusuf ◽  
Betti Ses Eka Polonia
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Steel Plate ◽  
Plate Thickness ◽  
Low Carbon Steel ◽  
Steel Plates ◽  
Low Carbon ◽  
Spring Back ◽  
Temperature Variations ◽  
Back Angle

The need for low carbon steel plate sheets with relatively thin thickness measurements in Indonesia is currently quite high, especially in supporting the automotive industry, the electronics industry, the food industry, beverages, and household appliances. To fulfill this, raw materials for low carbon steel plate sheets that have high formability and are not easily cracked in critical areas of the desired model are required. For this reason, research on the effect of temperature variations in heat treatment on hardness, microstructure and spring back of V-bending results on steel plates with a plate thickness of 0.8 mm. The research method used was a laboratory experimental method. The heat treatment is carried out with temperature variations of 710, 820 and 9300C with a holding time of 60 minutes. Tests carried out on specimens are hardness testing, microstructure testing, and spring back V-bending results on steel plates. The results of this study indicate a decrease in the spring back angle where the smallest spring back angle in the bending process is on the 9300C plate which is 1,040. The value of the hardness results from V-bending has increased significantly. The increase in the value of hardness because the plate has an atom shift or dislocation by shear stress (slip) due to plastic deformation on the plate. The highest hardness value is on the 7100C plate which is 154.67 HV or has an increase of 14,291% of the pre-bending plate. The lowest hardness value is on the 9300C plate which is 125.33 HV, its hardness increases 4.4% against the pre-bending plate. Heat treatment also causes changes in the microstructure of the plates from the process of regulation and reshaping of crystals to the growth of new grains which have implications for changes in mechanical properties and formability of the workpiece.

scholarly journals Hopkinson rod test results and constitutive description of TRIP780 steel resistance spot welding material

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 961-967
Author(s):  
Xiaomin Li ◽  
Jianrong Zhang
Keyword(s):  
Spot Welding ◽  
Steel Strip ◽  
Strain Curve ◽  
Test Machine ◽  
Strain Rates ◽  
Test Results ◽  
Welding Material ◽  
Static Tensile ◽  
Split Hopkinson ◽  
Brittle Fractures

Abstract A quasi-static tensile test was performed on a 1.4 mm-thick TRIP780 steel strip with welding points. An MTS810 material test machine was used in the test, and a Split Hopkinson tension bar device was used in performing impact stretch loading at different strain rates. The dynamic tensile stress–strain curve of the spot welding material with different strain rates was obtained through the finely designed Hopkinson rod test, and the strain rate dependence of a TRIP780 steel spot welding material was discussed. According to the dynamic constitutive equation of the TRIP780 steel spot welding material, the test results were numerically simulated, the constitutive description and test curves were compared, and the simulation results and test results were discussed and analyzed. The fractures of the test recovery specimen were scanned with the scanning electron microscope, and the fracture mechanism of the TRIP780 steel spot welding material was explored by observing the fractures. The surfaces of the fractures surface showed obvious cleavage river patterns, and the evolution process of microcracks was determined and used in characterizing brittle fractures in specimen spot welding sample subjected to dynamic stretch loading.

scholarly journals Investigations on arc brazing for galvanized heavy steel plates in steel and shipbuilding

2021 ◽  
Author(s):  
Philipp Andreazza ◽  
Andreas Gericke ◽  
Knuth-Michael Henkel
Keyword(s):  
Low Cost ◽  
Thin Sheet ◽  
Steel Structures ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Steel Plates ◽  
Galvanized Steel ◽  
Filler Materials ◽  
Static Tensile ◽  
Brazed Joints

AbstractArc brazing with low-melting copper-based filler materials, which has long been established and standardized in the thin sheet sector, offers numerous advantages in the processing of predominantly electrolytically galvanized steel structures. In steel and shipbuilding, on the other hand, equipment parts made of thick steel sheets are hot-dip galvanized at low cost and with good corrosion-inhibiting properties. Quality welding of such constructions is not possible without special precautions such as removing the zinc layer and subsequent recoating. With regard to greater plate thicknesses, arc brazing was analyzed in these investigations as an alternative joining method with regard to its suitability for practical use. Within the scope of the investigations, CuSi3Mn, CuMn12Ni2, and four different aluminum bronzes were examined on different sheet surface conditions with regard to the geometrical and production parameters. This was carried out by build-up and connection brazing, executed as butt and cross joints. Quasi-static tensile tests and fatigue tests were used to assess the strength behavior. In addition, metallographic analyses are carried out as well as hardness tests. The suitability for multi-layer brazing and the tendency to distortion were also investigated, as well as the behavior of arc brazed joints under corrosive conditions.

Comparison between Charpy Transition Temperature TCVN and Reference Temperature T° for 10Ni3CrMoV Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4488-4493
Author(s):  
Yi Fei Gao ◽  
Jun Chang Shen ◽  
Bo Qun Wu
Keyword(s):  
Heat Treatment ◽  
Transition Temperature ◽  
Material Design ◽  
Reference Temperature ◽  
Test Results ◽  
Test Technique ◽  
Fracture Appearance Transition Temperature ◽  
Qt Steels ◽  
Fracture Appearance ◽  
Lower Tolerance

Charpy transition temperature TCVN and reference temperature To for 10Ni3CrMoV steel were determined using two different experimental techniques such as Charpy V-notch impact test technique and reference temperature To test technique. It was found that two methods provided different test results. The median master curve with upper and lower tolerance bounds was got from the test. The upper tolerance bound is often used for material design and application. At the same time the TCVN and To results were discussed for two kinds of heat treatment which are QT(Quenching and Temper) and QLT(Quenching, anneal and temper). JC (med ) K values calculated were 101 and 105MPam1/2 for the QT and QLT steels, respectively. These indicated that the QLT steels have the higher JC (med ) K , the lower reference temperature and lower energy (or fracture appearance) transition temperature(ETT50 or FATT50) than the QT steels. This was mainly related with the different microstructures of two kinds of heat treatment.

Effect of Detailed Formations on the In-Plane Shear Capacity of Hairpin Connectors in Precast RC Floor Slabs

2010 ◽  
Vol 163-167 ◽  
pp. 1510-1514 ◽  
Author(s):  
Rui Pang ◽  
Shu Ting Liang ◽  
Xiao Jun Zhu ◽  
Yao Meng
Keyword(s):  
Simulation Analysis ◽  
Plate Thickness ◽  
Shear Capacity ◽  
Steel Plates ◽  
Strong Impact ◽  
Deformation Capacity ◽  
Initial Stiffness ◽  
Plane Shear ◽  
Floor Slabs ◽  
Strength And Deformation

Detailed formation of precast floor slab connectors has significant effect on their shear capacity, but there is no such specific provision on it at present. The effects of detailed formations on the shear strength, stiffness and deformation capacity of hairpin connectors(HPC) were studied, through numerical simulation analysis under in-plane shear force. The imbedded depth (d), slug length (h), steel plate thickness (t) and its stickout(s) were taken as parameters. The analysis results show that: ⅰ) the increase of imbedded depth can improve the bearing capacity and stiffness of HPC, but decrease the deformation capacity; ⅱ) with the increase of slug length, the HPC strength, stiffness and deformation capacity raised a lot; ⅲ) the steel plates’ thickness has small effect on the stiffness, but has strong impact on the strength and deformation capacity of HPC. ⅳ) the stickout can affect the initial stiffness and yield strength of HPC slightly, but has a considerable impact on its ultimate strength and deformation capacity. On the basis of analysis, recommendations on formation details of HPC are proposed for design and construction.

Flexural bearing capacity of RC hollow slab beam strengthened by steel plates of different thicknesses

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Long Liu ◽  
Lifeng Wang ◽  
Ziwang Xiao
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Plate Thickness ◽  
Research Field ◽  
Steel Plates ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Content Type ◽  
Flexural Bearing Capacity

PurposeThe flexural reinforcement of bridges in-service has been an important research field for a long time. Anchoring steel plate at the bottom of beam is a simple and effective method to improve its bearing capacity. The purpose of this paper is to explore the influence of anchoring steel plates of different thicknesses on the bearing capacity of hollow slab beam and to judge its working status.Design/methodology/approachFirst, static load experiments are carried out on two in-service RC hollow slab beams; meanwhile, nonlinear finite element models are built to study the bearing capacity of them. The nonlinear material and shear slip effect of studs are considered in the models. Second, the finite element models are verified, and the numerical simulation results are in good agreement with the experimental results. Finally, the finite element models are adopted to carry out the research on the influence of different steel plate thicknesses on the flexural bearing capacity and ductility.FindingsWhen steel plates of different thicknesses are adopted to reinforce RC hollow slab beams, the bearing capacity increases with the increase of the steel plate thickness in a certain range. But when the steel plate thickness reaches a certain level, bearing capacity is no longer influenced. The displacement ductility coefficient decreases with the increase of steel plate thickness.Originality/valueBased on experimental study, this paper makes an extrapolation analysis of the bearing capacity of hollow slab beams reinforced with steel plates of different thicknesses through finite element simulation and discusses the influence on ductility. This method not only ensures the accuracy of bearing capacity evaluation but also does not need many samples, which is economical to a certain extent. The research results provide a basis for the reinforcement design of similar bridges.

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