Showing papers on "Charpy impact test published in 1974"
TL;DR: In this article, a number of composites consisting of uniaxial carbon fibres in an epoxy resin matrix have been used for charpy impact tests and the results show that there is a critical length-to-depth ratio which marks a change of fracture mode from a relatively brittle transverse cracking to a tougher mode involving extensive delamination.
34 citations
TL;DR: In this article, four polymers, viz. polystyrene, polycarbonate, poly(methyl methacrylate), and poly-(vinyl chloride), were cooled from the melt to room temperature under hydrostatic pressures of 30 and 1000 atm.
Abstract: Four polymers, viz. polystyrene, polycarbonate, poly(methyl methacrylate), and poly-(vinyl chloride), were cooled from the melt to room temperature under hydrostatic pressures of 30 and 1000 atm. Cooling under high pressure increased the density by 0.4–0.6%, and the effect of this has been examined for the torsional creep properties, the dynamic properties at 1 Hz, the Charpy impact strength, the thermal expansivity, and the torsional yield stress. It turned out that, in general, densification affects the thermomechanical properties only slightly.
30 citations
TL;DR: The fracture behaviour of notched specimens of polymethylmethacrylate has been examined for a wide range of geometries in Charpy impact tests, and in tensile and slow bend fracture tests.
Abstract: The fracture behaviour of notched specimens of polymethylmethacrylate has been examined for a wide range of geometries in Charpy impact tests, and in tensile and slow bend fracture tests. It was found that the failure of the very sharply notched specimens was consistent with linear elastic fracture mechanics and defined a constant fracture toughness KIC for a constant notch tip radius, whereas the blunt notched specimens failed at a constant critical stress at the root of the notch.
20 citations
TL;DR: In this article, the authors determined the energy for initiation of fracture in each case was determined by measuring the area under the load-displacement curve up to limit load, and the value at the onset of crack propagation, J I D, was calculated from a plot of energy versus crack length.
Abstract: Rice's path-independent integral J of medium-strength alloys was determined under dynamic conditions by instrumented impact testing of precracked Charpy specimens. The viability of the instrumented Charpy technique for rapid and easy determination of useful fracture parameters is explained. Standard and side-notched Charpy specimens of Cr-Mo-V, H-11, and CG-27 alloys were precracked and tested. Load-displacement curves were generated for specimens with different fatigue precrack lengths. The energy for initiation of fracture in each case was determined by measuring the area under the load-displacement curve up to limit load. The value J at the onset of crack propagation, J I D , was calculated from a plot of energy versus crack length. The value of J I D is not affected by side notches. The slope of the energy versus crack length plot alters sufficiently to compensate for the reduction in thickness. Agreement is good between K I D values calculated from J I D measurements and by other methods.
18 citations
TL;DR: In this paper, high-speed crack velocity measurements were made using conductive silver grids applied to the specimens and the variation of K1c with strain rate and temperature was found to be small and in general agreement with expectations from the relaxation properties of polycarbonate.
Abstract: Crack velocity measurements and fracture toughness tests have been carried out on extruded sheets of bisphenol-A polycarbonate. Slow bend tests provided quasi-static K1c data while dynamic initiation values were obtained from instrumented Charpy impact tests. In both types of tests high-speed crack velocity measurements were made using conductive silver grids applied to the specimens. The variation of K1c with strain rate and temperature was found to be small and in general agreement with expectations from the relaxation properties of polycarbonate. Notch acuity was found to have little effect in that values of K1c and crack velocity from specimens having the standard Charpy notch were similar to values obtained from sharp-cracked specimens. Some anisotropy was present in the material and gave rise to a small variation in K1c values with direction of crack propagation. Crack velocity and also the fracture mode transition temperature showed considerable dependence upon orientation. It was thought that dynamic toughness Kd, was influenced more than K1c by partial orientation of amorphous regions in the material and that the relaxation time for re-orientation was probably significant here.
17 citations
TL;DR: In this article, the ductility loss can be attributed to hardening by vanadium nitrides, presumably in the form of thin-foil electron microscopy, and it was shown that vanadium in excess of 0·10% embrittles the heat-affected zone at high heat inputs.
Abstract: To obtain specified mechanical properties in high-strength steel plates, vanadium is often used as a grainrefiner and precipitation-strengthener. As excess microalloying is usually considered to impair the toughness of the heat-affected zone, an investigation with the aid of a weld cycle simulator was made. Eight steels of composition 0·15% C and 1·30% Mn with up to 0·45% V were studied. Submerged arc, electrogas, and hand welding were simulated in test-pieces from which Charpy V-notch specimens were prepared and tested for ductility and hardness. From these tests and metallography, including thin-foil electron microscopy, the following conclusions can be drawn. Vanadium in excess of 0·10% embrittles the heat-affected zone at high heat inputs. The transition, temperature increases with vanadium content in a semi-parabolic manner. At lower weld energies, a V content > 0·25% is detrimental to toughness. The ductility loss can be attributed to hardening by vanadium nitrides, presumably in the form of...
16 citations
TL;DR: In this paper, the dynamic fracture toughness, K I d, was measured in a number of ferrous alloys using precracked Charpy specimens and an instrumented impact machine.
Abstract: The dynamic fracture toughness, K I d , was measured in a number of ferrous alloys using precracked Charpy specimens and an instrumented impact machine. The alloys investigated included quenched and tempered steels (H-11, D6AC, and 4340), 18Ni maraging steels (grades 200, 250, and 300) and a high-temperature, stainless maraging steel (Pyromet X-15). Standard Charpy specimens were precracked in fatigue and tested at either 72°F (22°C) or -65°F (-54°C). Values of K I d were determined as a function of yield strength and microstructure, and correlations were established between K I d and both the energy to initiate fracture, W m /A, and the total energy of fracture, W/A. The instrumented, precracked Charpy test is shown to be a convenient method of determining relative fracture toughness; under proper conditions this test procedure can be used to determine the dynamic plane-strain fracture toughness.
14 citations
TL;DR: In this paper, the influence of sulfur content on the notch sensitivity of electroformed nickel was determined by Charpy impact tests, and a modified Izod test specimen containing the same joint configuration as the plated part described in the report was designed and evaluated.
12 citations
01 Jan 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the effect of an intercritical heat treatment on tempor embrittlement has been investigated for a rotor steel containing 0.25 pct C, 3.5 pct Ni, 1.7 pct Cr, 0.1 pct V, and deliberate additions of phosphorus, tin, or antimony.
Abstract: The effect of an intercritical heat treatment on tempor embrittlement has been investigated for a rotor steel containing 0.25 pct C, 3.5 pct Ni, 1.7 pct Cr, 0.5 pct Mo, 0.1 pct V, and deliberate additions of phosphorus, tin, or antimony. Both martensitic and bainitic steels were held at the intercritical temperature of 1380°F (750°C) for times up to 40 h and were then quenched or cooled to obtain martensitic or bainitic transformation. The steels were then tempered, followed by water quenching or step cooling from the tempering temperature. The residual ferrite maintained a fine plate-like shape even after 40 h at the intercritical temperature. Embrittlement induced by step cooling from the final tempering was mark edly reduced by the intercritical treatment as compared to the embrittlement observed after conventional heat treatment; for example, AFATT, the increase in the Charpy V-notch 50 pct shear fracture transition temperature caused by step cooling, was reduced by at least 80°F (45°C) as a result of the intercritical treatment of steels containing 0.02 pct P. Molybdenum effectively reduced AFATT in intercritlcally heat-treated steels as well as in conventionally treated steels. Possible mechanisms for reducing temper embrittlement with the intercritical treatment are discussed.
12 citations
01 Aug 1974
TL;DR: In this article, the influence of microstructure and strength on the fracture toughness and fracture mechanism of an 18 Ni, 300 grade maraging steel was investigated using fracture and metallographic sectioning.
Abstract: Fractography and metallographic sectioning were used to investigate the influence of microstructure and strength on the fracture toughness (KIc) and fracture mechanism of an 18 Ni, 300 grade maraging steel. Increased yield strength from 1442 to 2070 MN/m squared through precipitation hardening results in a KIc loss from 143 to 55 MN/m superscript 3/2. Ti (C,N) Ti2S, and TiC inclusions in sizes from 1 to 8, 1 to 15, and 0.1 to 2 microns respectively serve as sites for void nucleation and lead to fracture by the dimpled rupture process in all strength levels considered. TiC nucleated dimples occupy more than half the fracture in all conditions. Void nucleation rate and resultant number of dimples per unit area of fracture increase with increasing yield strength. Average dimple size decreases with increasing strength and/or overaging which follows from the decreasing amount of stable void growth measured by sectioning tensile specimens. Void growth is assisted by crack branching along a path of TiC inclusions. Coalescence occurs in the highest strength materials by a combination of TiC void nucleation and premature separation at strengthening precipitates.
11 citations
01 Feb 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, massive electrodeposits of nickel and Ni−Co alloys ranging up to 43 pct Co were examined microstructurally and tested to determine tensile properties and static and dynamic fracture toughness.
Abstract: Massive electrodeposits of nickel and Ni−Co alloys ranging up to 43 pct Co were examined microstructurally and tested to determine tensile properties and static and dynamic fracture toughness. Specimens were also tested after being annealed at 575 K. Annealing increased grain size, decreased yield, and ultimate strengths, and increased ductility and dynamic toughness. The as-plated Ni-43 Co was the only material to exhibit validK
IC values, averaging about 38 MN/m3/2. In instrumented dynamic tests on precracked Charpy bars, the same material exhibited aK
Id of 50 MN/m3/2. The yield strength of the Ni-43 Co alloy was 1154 MN/m2. All the materials tested showed dimpled, ductile rupture fracture surfaces. The Hall-Petch behavior of the nickel indicated that it is much easier to initiate flow in normal grain boundary structures than in structures composed of dislocation cell walls.
01 Sep 1974
TL;DR: In this paper, the ability of past and present steel highway bridges to withstand brittle fracture has been investigated and the use of these measures of fracture toughness and fracture mechanics in general are discussed as they apply to design, inspection and fabrication of bridges.
Abstract: The ability of past and present steel highway bridges to withstand brittle fracture has been investigated. To this end, the static fracture toughness, the dynamic fracture toughness, the dynamic tear energy (DT) and the Charpy impact properties (CVN) of eight steels common to bridge constructions have been measured over a temperature range of about -200 degrees F to +75 degrees F. The steels studied were A7, A36, A242, A440, A441, A588, A514 and A517. The use of these measures of fracture toughness and fracture mechanics in general are discussed as they apply to design, inspection and fabrication of bridges. The present AASHTO CVN requirements for bridge steels were evaluated in relationship to the finding of the program. These requirements were judged adequate for structures where parallel load paths exist. For structures where the loads are carried by only one load path more detailed material evaluations are recommended in place of the AASHTO CVN requirement. /FHWA/
TL;DR: In this paper, the flexural strength at high strain rates and the energy absorbed in Charpy impact fracture of an alumina were measured by use of strain-gage instrumentation to record impact loads as a function of time.
Abstract: By use of strain-gage instrumentation to record impact loads as a function of time, the flexural strength at high strain rates and the energy absorbed in Charpy impact fracture of an alumina were measured. The energy absorption by Al2O3 impact specimens is shown to result principally from elastic mechanical loading. Extraneous energy losses in the Charpy test can easily exceed the magnitude of this mechanical specimen-loading energy and are shown to be inherent sources of error in impact testing of brittle materials.
TL;DR: In this paper, the authors used the visioplasticity method to obtain the stress and strain distributions during planestrain bending in a standard Charpy V-notched specimen of low carbon steel.
Abstract: T he visioplasticity method has been used to obtain the stress and strain distributions during planestrain bending in a standard Charpy V-notched specimen of low carbon steel. The specimen was slit longitudinally through the notch with a square grid inscribed on the interface. The instantaneous grid distortion was obtained during a three-point incremental bending test. A computer program was developed for the calculation of the instantaneous stress and strain distributions using the experimentally determined displacement field and the true stress-strain curve of the steel.
TL;DR: In this article, the hardness, tensile, and impact properties of two nickel-molybdenum powder-formed steels were determined using standard 25 mm-dia. specimens with a 25 mm gauge length.
Abstract: Hardenability, tensile, and impact properties have been determined for two nickel-molybdenum powder-formed steels. The compositions of the two steels were Fe-1·8% Ni−0·5% Mo and Fe −0·5% Ni −0·6% Mo; carbon contents studied for both materials were 0·2, 0·3, and 0·4%. Preforms (50 × 50 × 127 mm) were pressed and then sintered for 1 h in a dissociated ammonia atmosphere at 1120°C, to provide a density of 6·5 g/cm3. Preforms were hot formed to full density by upsetting (plane strain) at 980°C or by re-pressing (uniaxial strain) at 1040°C.Standard 25 mm-dia. × 100 mm-long Jominy end-quenched tests were made to determine hardenability. Room-temperature tensile properties were determined using 6·4 mm-dia. specimens with a 25 mm gauge-length. Standard Charpy V-notch specimens were used to determine the impact properties at −40, 0, 22, and 100°C. Triplicate tests were made in the as formed as well as the quenched-and-tempered conditions.The additional flow that was realized by upsetting provided higher te...
TL;DR: In this paper, the Charpy impact test was studied in detail via instrumentation of both the tester and the specimen, and it was found that the energy associated with the impact testing of cemented carbide consists mainly of elastic bending energy and absorption of energy by the testing machine.
Abstract: In an effort to better understand the nature and the limitations of impact testing, the Charpy impact test was studied in detail via instrumentation of both the tester and the specimen. It was found that the energy associated with the impact testing of cemented carbide consists mainly of elastic bending energy and absorption of energy by the testing machine. The vibrational and plastic components are insignificant. The toss energy and energy necessary to create new surfaces can be fairly well calculated from other considerations. The tests have shown no rate effects in cemented carbides, and the state of stress in the beam is uniaxial tension. Thus the test does not describe the material's propensity for cleavage or brittle failure, but rather describes mainly the modulus and strength of cemented carbides (which are routinely and more easily measured in other ways), and the stiffness of the testing machine-all of which have very little bearing on the toughness of the cemented carbide. The components which describe this are the energy of plastic work and the energy necessary to create two new surfaces, and these consist of only a few percent of the total measured energy. The amount of energy which the machine absorbs will vary with the modulus and strength of the material being tested. In the case of a hard low-strength grade like Carboloy 2 Grade 320, the anvil sees very little load before failure and thus the energy partitioning will be significantly different than that for a stronger grade. The Charpy test conducted with the conditions in this study has little value in ascertaining the toughness of cemented carbide; in fact, results from it may be misleading. When cemented carbide is evaluated for toughness by impact testing of any kind, careful attention must be given to the aforementioned factors because they are encountered to a large extent in most, if not all, types of impact tests. Charpy impact-type tests on cemented carbide are essentially fast transverse-rupture strength tests on a "soft" test machine.
TL;DR: The influence of manganese on the 50% fibre Charpy impact transition temperature of low-silicon and silicon-killed steels has been examined in this paper, where the steels were found to have similar grain-boundary carbide thicknesses so that the changes in the transition temperature could be related almost entirely to changes occurring in the ferrite.
Abstract: The influence of manganese on the 50% fibre Charpy impact transition temperature of as-rolled low-silicon and silicon-killed steels has been examined. The steels were found to have similar grain-boundary carbide thicknesses so that the changes in the transition temperature could be related almost entirely to changes occurring in the ferrite. Whereas manganese had only a small influence on the transition temperature of silicon-killed steels, a very significant improvement occurred with low-silicon steels, a rise of 1% manganese causing an approximate 40°C lowering of the impact transition temperature after correcting to constant grain size and pearlite volume fraction. The decrease in transition temperature is believed to be due predominantly to the prevention of grain-boundary segregation of nitrogen by manganese, as is shown by the accompanying fall in ky value and the lack of any increase in the hardness of ferrite grains close to their grain boundaries.
TL;DR: Temper embrittlement of low alloy steels (Ni and Mn) was studied by means of Auger electron spectroscopy, scanning electron microscopy and Charpy test as mentioned in this paper.
Abstract: Temper embrittlement of low alloy steels (Ni and Mn) was studied by means of Auger electron spectroscopy, scanning electron microscopy and Charpy test. Addition of nickel (less than 10 wt%) increased segregation rate of phosphorus (less than 0.09 wt%) to free surfaces by the factor of 10–100 compared to that in Fe–P alloys at 500°C. Manganese steel was investigated to discuss the relation between the amount of phosphorus in the prior austenite grain boundary and the degree of embrittlement. Modified V-notch Charpy specimens were fractured in a UHV apparatus at the temperature of -150°C. It was concluded that the temper embrittlement in the manganese steel is dominantly attributed to the segregation of phosphorus to the prior austenite grain boundaries.
TL;DR: In this article, a detailed investigation of specimen mechanical performance and specimen-fixture interaction was undertaken to evaluate the instrumented impact test as a reliable way of collecting high strain rate, plane strain fracture toughness data.
Abstract: To evaluate the instrumented impact test as a reliable way of collecting high strain rate, plane strain fracture toughness data, a detailed investigation of specimen mechanical performance and specimen-fixture interactionwas undertaken. Finite element techniques were applied to calculate the compliance and stress intensity values for Charpy specimens subjected to both roller and pinned supporting conditions. For comparison, experimental compliances were gathered for 7075-T6 aluminum and 1018 steel Charpy specimens tested in slow and fast bending. The results indicate that both small specimen size and anvil friction can affect the interpretation of fracture load data used for K I D calculations.
TL;DR: In this paper, the effect of response time on instrumented Charpy impact data obtained on unidirectional Borsic-aluminum composites has been examined and it has been shown that the use of filters to eliminate highfrequency noise in the load-time traces obtained can significantly increase the response time of the testing system and lead to grossly inaccurate data.
Abstract: The effect of response time on instrumented Charpy impact data obtained on unidirectional Borsic-aluminum composites has been examined. It has been shown that the use of filters to eliminate high-frequency noise in the load-time traces obtained can significantly increase the response time of the testing system and lead to grossly inaccurate data. The current results indicate that as the response time is increased, the load is attenuated, the time to fracture is increased, and the absorbed energy is unaffected. The attenuation characteristics of the testing system can be documented through the use of a sine wave generator. These characteristics can be used both as a guide to ensure the adequacy of the system response time for future testing and as a means of correcting attenuated data which were obtained on a testing system with excessive filtering (inadequate response times).
TL;DR: In this paper, the authors used the equivalent energy-area criterion to relate the toughness data obtained from subsize and standard size Charpy V-notch impact specimens, including precracked Charpy toughness (W/A) and fracture toughness (K I c ), for defining the toughness characteristics of monolithic high-hardness armor steels.
Abstract: The purpose of this program was to generate meaningful toughness parameter data that could be incorporated into existing high-hardness steel armor specifications. Various toughness parameters, including Charpy V-notch impact, precracked Charpy toughness (W/A) and fracture toughness (K I c ), were explored for defining the toughness characteristics of monolithic high-hardness armor steels. Materials from three producers were investigated in thicknesses ranging from 0.125 to 0.750 in. The equivalent energy-area criterion was utilized to relate the toughness data obtained from subsize and standard size Charpy V-notch impact specimens. Results of this investigation show that the energy requirements, as set forth in the military specification for high-hardness armor steels, are met by each producer's material when the plate thickness is sufficient to use the standard size Charpy V-notch impact specimen. The equivalent energy-area criterion represents a usable approach for the interpretation of data obtained from subsize impact specimens and should now suffice to define an interim specification for the subsize Charpy test. The other toughness parameter results, plus hardness and tensile properties, are presented and discussed.
TL;DR: This article showed that the transverse Charpy V notch shelf energy improved with decreasing sulphur content and with increasing amounts of hot rolling in the longitudinal and transverse direction, respectively, and that the shelf energy was inversely proportional to the length of the manganese sulphide inclusions in the direction of crack propagation.
Abstract: Studies of plates rolled from laboratory heats of 0·19C–1·20Mn Si-Al-killed steel showed that the transverse Charpy V notch shelf energy improved with decreasing sulphur content and with increasing amounts of hot rolling in the transverse direction. Hot-rolled plates with a low finishing temperature (control rolled) had slightly lower shelf energy than did regular hot-rolled plates, and additions of vanadium or niobium lowered the shelf energy of both hot-rolled and control-rolled plates. The length and width of the sulphides were proportional to the amount of reduction in the longitudinal and transverse directions, respectively. The shelf energy was inversely proportional to the length of the manganese sulphide inclusions in the direction of crack propagation. Directionality in shelf energy was minimized only by increasing the amount of cross rolling or by the use of very low sulphur contents.
TL;DR: In this article, the dynamic fracture toughness was determined for two titanium alloys (Ti-6A1-4V and Ti-6a1-6V-2Sn) from different suppliers and in various heat-treated conditions.
Abstract: The dynamic fracture toughness was determined for two titanium alloys (Ti-6A1-4V and Ti-6A1-6V-2Sn) from different suppliers and in various heat-treated conditions. The strain-rate effect associated with the dynamic test is shown to increase the fracture toughness for all the alloys with the exception of mill-annealed and duplex-annealed Ti-6A1-6V-2Sn, where the fracture toughness was found to be independent of strain rate. Dial energy per unit specimen area (W/A) d for precracked Charpy specimens can be used to calculate K I d as long as a relatively flat fracture appearance (small shear area) is obtained. Otherwise, when a large amount of shear is present, the energy to maximum load (W/A) m or P m a x from the load-time trace must be used to calculate K I d .
TL;DR: In this article, the effects of shape of pores on toughness and ductility of sintered iron were investigated and the results were summarized as follows: 1) The roundness of the pores caused an increase in the charpy shelf energy and made the ductile-brittle transition more evident.
Abstract: It is the purpose of this study to investigate the effects of shape of pores on toughness and ductility of sintered iron.Compacts with a density range of 5.9-7.6 g/cm3 were pressed from electrolytic iron powder and pre-sintered at 1100°C for 10 min in hydrogen. Subsequently they were infiltrated with ferrous chloride by soaking for 4 min in its melt at 750°C.Activated-sintering (or reduction of ferrous chloride) was carried out at 800°C, 950°C and 1100°C for 5 min-3 hr in hydrogen. Impact and tensile properties of these materials with round pores were compared to those of conventionally sintered ones with sharp edged pores.The results were summarized as follows.1. The roundness of the pores caused an increase in the charpy shelf energy and made the ductile-brittle transition more evident.For this reason, the impact strength of the activation-sintered iron was, at 200°C, about two times as large as that of conventionally sintered iron with the same density, but at low temperatures, smaller than that.2. Activated-sintering increased the ultimate tensile strength and the fracture strain by 10-50% over conventional sintering. But the yield strength was hardly affected by the pore shape.3. The relative strength and the fracture strain of porous materials were expressed as functions relating not only to the porosity but also to the notch effect of the pores.
01 Mar 1974
TL;DR: In this article, the properties of multi-angle and hybrid graphite reinforced epoxy resin composites from the perspective of property trade-off studies have been evaluated using Modulite 5206 basic graphite fiber orientations.
Abstract: : Notched and unnotched instrumented Charpy impact data and tensile, flexural, compressive and shear property data of multi-angle and hybrid graphite reinforced epoxy resin composites are presented from the perspective of property trade-off studies. Two Modulite 5206 basic graphite fiber orientations are evaluated; composites in which the filament repeating unit direction is 1) 0 degrees, and 2) 0 degrees, + 45 degrees, -45 degrees and 90 degrees. The hybrid configurations are fabricated using the basic graphite orientations with discrete amounts of supplementary third phase fibers (glass, Nomex, and PRD-49 Type III) interspersed in the composites in 0 degree and in -45 degree and + 45 degree directions. (Author, modified-PL)
10 Jul 1974
TL;DR: In this article, a new fracture control guidelines for welded ship hulls have been proposed as a result of an investigation sponsored by the Ship Structure Committee, which include fracture toughness requirements in terms of the Drop Weight-NDT temperature and Dynamic Tear (DT) energy.
Abstract: New fracture control guidelines for welded ship hulls have been proposed as a result of an investigation sponsored by the Ship Structure Committee. These guidelines include fracture toughness requirements in terms of the Drop Weight-NDT temperature and Dynamic Tear (DT) energy. To aid the implementation of these criteria an exploratory program was undertaken to characterize the dynamic fracture toughness of ordinary-strength shipbuilding steels, namely, ABS Grades A,B,C,D,E, and CS. Test materials (plate) were obtained at random from several shipyards and steel mills in an effort to characterize the products of current steel making practice. Fracture toughness trends were defined by means of Drop Weight-NDT, 1-in. DT and standard Charpy V-notch tests and the observed toughness characteristics were compared with the proposed toughness criteria. Non-heat treated plates of ABS Grades A,B, and C were found to have insufficient toughness to meet reasonable fracture toughness requirements. On the other hand, normalized plates ofABS Grades C,D,E, andCS were found to exhibit improved toughness trends that could meet the proposed requirements in most cases.
01 May 1974
TL;DR: In this article, a wide range of microstructures were obtained in Fe-Mn alloys by varyirig the manganese and chromium contents, and it was found that increasing amounts of manganous were found to be detrimental to low temperature toughness.
Abstract: A wide range of microstructures were obtained in Fe-Mn alloys by varyirig the manganese and chromium contents. When a bcc (a) structure was produced, increasing amounts of manganese were found to be detrimental to low temperature toughness. At manganese levels greater than'12% where appreciable amounts of E and y phases formed the ductiie-brittle transition temperature dropped rapidly. In terms of the (€+ y) phases present, the ductile-brittle transition temperatu~e decreased at a rate ofl. 3°C/vb1% (E + yr. Increasing the (€ + y) content to achieve good low temperature toughness, however, also caused a decrease in the yield strength •. Increases in the yield strength were achieved without appreciable increase in the ductile-brittle transition temperaiureby greater' manganese additions and by chromium additions.
TL;DR: In this paper, the effect of shock strengthening on impact properties of Type 316 stainless steel at temperatures ranging from room temperature to 650°C (1202°F) was established by utilizing the instrumented Charpy impact test.
Abstract: The effect of shock strengthening on impact properties of Type 316 stainless steel at temperatures ranging from room temperature to 650°C (1202°F) was established by utilizing the instrumented Charpy impact test. It was found that the total impact energy absorbed progressively decreases with increasing shocking pressure. The dynamic yield strength (o d y ) was increased by increasing the shocking pressures for all testing temperatures. This trend is expected because the static yield strength (σ s y ) was also found to increase with increasing shocking pressure. However, the ratio of dynamic-yield to static-yield strengths (measure of strain-rate sensitivity) was found to decrease with increasing shocking pressure.
TL;DR: In this article, the results of instrumented low-blow testing and three-point bend testing of ring-shaped specimens are compared with similar results from instrumented Charpy tests.
Abstract: The Charpy impact test is rapidly being upgraded to include instrumentation for revealing the load history of the specimen while it is being fractured in three-point bending. Unfortunately, similar interest in upgrading the Izod test (cantilever bending) has been notably lacking. The first part of this paper discusses the results of a recent study of techniques for instrumenting the Izod test. Results from both standard and nonstandard Izod specimen tests are compared with similar results from instrumented Charpy tests. Also included are the results of instrumented Izod tests of tubular specimens of aluminum, steel, and composite materials. Instrumented low-blow testing and three-point bend testing of ring-shaped specimens are typical variations of the instrumented Charpy impact test. These two test techniques are also discussed in this paper. There is hope that these and other variations in test techniques will lead to new inexpensive methods of evaluating material and small structure behavior under adverse loading conditions.
01 Mar 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, a study of the influence of carbide phases on the cracking resistance of Mo-B steels was conducted using notched or notched and precracked specimens that were subjected to impact, cyclic, and monotonically increasing loading.
Abstract: A study of the influence of carbide phases on the cracking resistance of as-quenched and of quenched and tempered 0.5 pct Mo-B steels was made using notched or notched and precracked specimens that were subjected to impact, cyclic, and monotonically increasing loading. The carbide influence on fracture, while limited in extent, was found to increase as load, loading rate, volume fraction, and particle size increase. The results for the asquenched condition showed that the susceptibility of these steels to crack initiation under impact loading at temperatures below - 100°F is greater when even a small amount of titanium carbide (less than 0.2 vol pet of 1 to 5 μm particles) is present than when none is present. At room temperature, this same carbide concentration has no influence on impact properties, fatigue-crack initiation (in the presence of a notch), fatigue-crack growth rate, or the ductile fracture resistance under monotonically increasing loading at slow strain rate. In the case of the quenched and tempered materials, the alloy containing a large amount of M23C6 (2 vol pct of 1 to 10 μm particles) exhibited behavior similar to that observed in the as-quenched materials containing titanium carbide. That is, the presence of M23C6 was associated with increased susceptibility to crack initiation for impact loading at low temperature. In addition, at room temperature this alloy had a reduced impact energy for crack propagation. For monotonically increasing loading at slow strain rate, this same carbide distribution had no influence on the net section stresses required to initiate stable or unstable crack growth. These stresses fall closely in line with, respectively, the yield stress and tensile strength of the material. The alloy containing M23C6 required less crack opening for a given crack extension—an effect most pronounced after maximum load. Finally, some attention is directed to the use of Charpy test data to assess fracture resistance for modes of loading other than impact.