Showing papers on "Hardness published in 1983"
TL;DR: The Schmidt hammer is employed by geomorphologists as a convenient field instrument for measuring the hardness of rock surfaces as mentioned in this paper, and the results obtained are a function of not only the hardness but also their texture.
Abstract: The Schmidt hammer is employed by geomorphologists as a convenient field instrument for measuring the hardness of rock surfaces. Field trials indicate that the readings obtained are a function of not only the hardness of the surfaces but also their texture. Smooth planar surfaces give much higher readings than rough or irregular surfaces. This makes interpretation of the results particularly difficult when the hammer is used to measure the hardness of natural rock surfaces that have been roughened by weathering.
73 citations
TL;DR: In this article, a column of abrasive contained in a tube and pressed against a rotating metal disc was examined as a function of the length of the wear path, load, speed and abrasive size, abrasive hardness, metal hardness and temperature.
50 citations
TL;DR: The Wallace hardness of four visible light activated resins was investigated and the prevailing part of the increase in surface hardness was found within the first few min after irradiation and this pattern was similar in all resins independent of light source.
Abstract: – The Wallace hardness of four visible light activated resins (Durafill, Heliosit, Silux and Visio-Dispers) was investigated at different times from 1 min and 35 s up to 60 min after start of irradiation. The prevailing part of the increase in surface hardness was found within the first few min after irradiation and this pattern was similar in all resins independent of light source.
47 citations
TL;DR: In this article, the relative contributions of microplasticity and microfracture to material failure during compression testing and microhardness indentation were investigated in strong ceramics.
Abstract: Hardness and compressive strength of several strong ceramics are measured from room temperature to 1000° C. Similarities in behaviour, and the results of microscopic examination, are interpreted in terms of the relative contributions of microplasticity and microfracture to material failure during compression testing and microhardness indentation. It is shown that microplasticity alone is an insufficient basis upon which to relate material response under the two test conditions, and that tensile microfracture is a significant contributor both to compressive failure and to subsurface indentation deformation, hence to hardness.
46 citations
Patent•
02 Sep 1983
TL;DR: In this article, a component of titanium or alloys thereof is placed in an autoclave for three hours to a pressure of 900 bar and a temperature of 1000° C. The TiN layer thus formed in the surface and subsurface-zone of the component has a Vickers hardness of 800 0.05 g/sq.mm.
Abstract: A component of titanium or alloys thereof is placed in an autoclave. Nitrogen gas or ammonia is pumped into the autoclave. The chemically untreated component is exposed in the autoclave for three hours to a pressure of 900 bar and a temperature of 1000° C. The TiN layer thus formed in the surface- and subsurface-zone of the component has a Vickers hardness of 800 0.05 g/sq.mm. with a thickness of 20 microns. With this economical method, an increase in surface hardness from Vickers hardness 0.05 =450 with prior art methods to Vickers hardness 0.05 =800 is achieved.
30 citations
TL;DR: In this paper, the impact of ZnS by a pyramidal projectile was used to provide a measurement of the dynamic hardness and to obtain direct comparison of the contact damage produced by static loading and impact.
Abstract: Impact of ZnS by a pyramidal projectile was used to provide a measurement of the dynamic hardness and to obtain direct comparison of the contact damage produced by static loading and impact. The dynamic hardness was evaluated from measurements of residual contact dimensions as a function of impact velocity, over the velocity range 5 to 40 m.s-1. The value obtained (Hd=5.0 GPa) was higher than the static hardness (HS= 1.9 GPa). The higher hardness in impact causes more extensive cracking, an increase in the elastic recovery of the depth of the residual contact impression, and a smaller plastic zone surrounding the contact site. The relative extents of cracking in impact and static loading are predicted by a quasistatic indentation fracture mechanics analysis along with the appropriate values of hardness.
30 citations
TL;DR: In this paper, the ion nitriding was performed at a net r.f. power of 400 W at substrate temperatures of 450-500 °C, and the surface hardness was substantially increased from a Vickers hardness VHN of 290 kgf mm-2 for untreated samples to a maximum VH N of 1200 kgf µm 2 for samples treated in a plasma sustained in a gas mixture with N2:H2 = 1:1.
24 citations
TL;DR: A review of ion implantation studies supported by surface analysis finds that the principal benefit of ion insertion is to prevent or delay the formation of wear particles, thereby changing the wear mode during run-in and permitting metals to reach load-carrying capacities up to their elastic limits as mentioned in this paper.
Abstract: A review of tribomechanical studies supported by surface analysis finds ion implantation capable of increasing the sliding wear resistance of ion implanted metals in two ways. First, it can reduce friction by modifying the surface composition (e.g. Ti+ into steel) or by promoting the growth of low friction oxide layers (e.g. N into Ti). Second, it can modify the subsurface composition and structure to resist fracture and debris formation. These modifications harden the surface, change its work-hardening behavior and/or increase residual stresses. Microindentation hardness measurements indicate that many but not all of the wear resistant surfaces are hardened by implantation; thus, surface hardness is a contributing but not necessarily a controlling factor in wear resistance. These mechanisms of wear reduction and the chemical and microstructural modifications responsible for them are discussed. Evidence for wear reduction through the migration of N during wear is critically reviewed. It is concluded that the principal benefit of ion implantation is to prevent or delay the formation of wear particles, thereby changing the wear mode during run-in and permitting metals to reach load-carrying capacities up to their elastic limits.
21 citations
TL;DR: In this article, the surface hardness of a polyethylene sheet was enhanced by a coating of plasma films prepared from TMS or the TMS/O2 mixtures, and the results showed that the adhesion between these plasma films and polyethylenes sheet was good even when immersed in 0.9% NaCl solution at 40°C for 10 days.
Abstract: Glow discharge polymerizations of tetramethylsilane (TMS) were performed by the capacitive coupling of a 20 kHz frequency in comparison with those by the inductive coupling of a 13.56 MHz frequency. The polymers prepared by the former coupling were poorer in carbon and hydrogen, but richer in silicon than those prepared by the latter coupling. These two polymers showing similar infrared spectra contained CH3, CH2, CH, SiOC, SiOSi, SiCH3, and SiCH2CH2Si groups. Some physical properties involving surface energy, thermal stability, and absorption spectra in the regions of the UV and visible light were determined. This coating procedure was applied for surface hardening of a polyethylene sheet. The surface hardness of the polyethylene sheet was enhanced by a coating of plasma films prepared from TMS or the TMS/O2 mixtures. Surface hardness was determined by the pencil method and hardness was enhanced from 2B to 2H. The adhesion between these plasma films and polyethylene sheet was good even when immersed in 0.9% NaCl solution at 40°C for 10 days.
21 citations
TL;DR: In this article, it is shown that the degree of ploughing decreases as the hardness of the material being tested increases, and that the dependence of the amount of wear on the mechanical properties of the abraded material depends primarily on ductility and not on hardness.
13 citations
Patent•
31 Aug 1983
TL;DR: In this article, a component made of titanium or its alloys is placed in an autoclave, and Nitrogen gas or ammonia is pumped into the autocorvability of the component.
Abstract: The component made of titanium or its alloys is placed in an autoclave. Nitrogen gas or ammonia is pumped into the autoclave. The chemically untreated component is exposed to a pressure of 900 bar and a heat of 1000 ° C for three hours in the autoclave. The TiN layer thus formed in the edge zone of the component has a hardness of HV 0.05 with a thickness of 20µ. In this inexpensive process, an increase in surface hardness from HV 0.05 = 450 of the known processes to HV 0.05 = 800 is achieved.
TL;DR: In this article, the effect of surface hardness on scuffing was investigated using a two-disc machine and the results showed that quenched discs of the highest surface hardness, in which the improvement in surface roughness and the formation of an oxide film are expected to be small, offered the poorest resistance to scuffings.
TL;DR: In this article, a motor-driven, spherical probe attached to a load cell was used to measure the external force needed to fracture the uppermost elements of several natural snow surfaces.
Patent•
20 Sep 1983
TL;DR: In this article, the surfaces of a master stamper and a dome stammer are coated with nitrides of aluminum or chromium such as AlN, CrN, and Cr3N2.
Abstract: PURPOSE:To obtain a stamper which is durable to many-time use while improving its surface hardness, by coating surfaces of a master stamper and a dome stamper with nitrified films of aluminum or chromium. CONSTITUTION:The surfaces of the master stamper and dome stamper used as original disks for plastic molding are coated with nitrides of aluminum or chromium such as AlN, CrN, and Cr3N2, and their hardness is increased to improve their durability. For the formation of them, the stampers formed by Ni electroforming are defatted and dried, and then Al or Cr is vapor-deposited and annealed. Then, the stampers are put in a nitrifying chamber and while gaseous NH3 is fed, they are heated to produce nitrides.
Patent•
05 Nov 1983
TL;DR: In this article, a high-strength pinion for steering having 650- 750Hv surface hardness and 0.7-1.2mm hardness was used for carburization and hardening.
Abstract: PURPOSE:To remarkably enhance the strength of Cr-Mo case hardening steel having specified hardenability by carburizing the steel under specified conditions and by hardening and tempering it under specified conditions. CONSTITUTION:Cr-Mo case hardening steel having 27-30 Jominy value as the material of a pinion for steering is carburized at 930-970 deg.C for 2.5-5hr. It is held at 850-880 deg.C hardening temp. for 30-60min, dipped in hot oil, and tempered at 200-250 deg.C for 1-2hr. A high-strength pinion for steering having 650- 750Hv surface hardness and 0.7-1.2mm. available depth of carburization and hardening (513 Hv) at the pitch circle part is obtd.
Patent•
22 Jan 1983
TL;DR: In this article, the hardness and dyeability for alumite of an Al alloy was improved by composing said alloy of the specific compsn contg Zn, Mg, Cu, Cr, Ti, Zr, Si, Fe and contg of the balance substantially Al.
Abstract: PURPOSE:To improve the hardness and dyeability for alumite of an Al alloy by composing said alloy of the specific compsn contg Zn, Mg, Cu, Cr, Ti, Zr, Si, Fe and contg of the balance substantially Al CONSTITUTION:This Al alloy of superior dyeability for alumity and high hardness has the following compsn: Said compsn contains 55-65% Zn, 25-35% Mg, 056-066% Cu, 016-026% Cr, 0011-0021% Ti, 008-018% Zr, <=009% Si, <=017% Fe, and consists of the balance substantially Al The surface hardness of such alloy is at a level of about 78-83HRB which compares equally with that of extra super duralumin, and the alumite dyeability of the alloy is equivalent to that of 3-nine class hgh purity Al
Patent•
18 Oct 1983
TL;DR: In this article, a diffused Al layer with low hardness, superior workability and superior strength at high temperature was formed by diffusing Al at a specified temp. of 1,000-1,250 deg.C in a nonoxidizing atmosphere.
Abstract: PURPOSE:To form a diffused Al layer with low hardness, superior workability and superior strength at high temp., by diffusing Al at a specified temp. in the surface of each of parts made of high alloy steel used in an atmosphere of hot combusting gas and by carrying out after-heat-treatment at the same temp. CONSTITUTION:Al is diffused at 1,000-1,250 deg.C in the surface of each of parts made of stainless steel or higher alloy steel used in an atmosphere of hot combustion gas such as parts of a boiler or a heat exchanger to form an Al-enriched layer having >=10mum thickness. Afterheat-treatment is then carried out by heating at the same temp. of 1,000-1,250 deg.C in a nonoxidizing atmosphere. A surface treated layer having lower surface hardness than a material subjected to conventional Al diffusion is formed. The layer has superior strength at high temp. as well as supeiror workability.
01 Jan 1983
TL;DR: In this paper, an in depth study of the parameters associated with the ESD process and the wear resistance of the coatings is performed, which is similar to a micro-welding process.
Abstract: A common method to improve wear resistance of metals in rubbing contact is to increase their surface hardness. Electro-Spark Deposition is a process which uses capacitive discharge pulses of high current passing through a hard carbide electrode in contact with and scanning the metal surface to be hardened. The result is a thin, hard, adherent coating of carbide deposited with a minimum of heat influence on the substrate and a significant increase in wear life of the coated metal. Electro-Spark Deposition is similar to a micro-welding process. It is a simple, portable and inexpensive coating method, which has great potential for commercial utilization. This thesis is an in depth study of the parameters associated with the ESD process and the wear resistance of the coatings.
Patent•
22 Jan 1983
TL;DR: In this paper, a roll with a negative temperature gradient extending from its inside hole surface toward the outside surface is made, and after quenching, residual austenite is converted to martensite.
Abstract: PURPOSE:To obtain a roll which is large in its surface hardness and hardening depth, by making a work roll having a negative temperature gradient extending from its inside surface toward the outside surface, when converting residual austenite to martensite after quenching. CONSTITUTION:The whole roll for cold rolling is heated and quenched, and after that, for instance, the surface and the inside hole surface are set to -100 deg.C and 0 deg.C, respectively, and the roll is made to have a negative temperature gradient extending from its inside hole surface toward the outside surface. Subsequently, after quenching, residual austenite is converted to martensite. In this way, decomposition of the residual austenite is quickened without tempering after quenching, and a roll which is large in its surface hardness and hardening depth is obtained.
Patent•
29 Jun 1983
TL;DR: In this article, a decorative material having high surface hardness by coating the paint mixed with flaky pigments having high hardness and additives for relieving said flaky pigsments on the surface of a base material and allowing the paint to cure is presented.
Abstract: PURPOSE:To produce a decorative material having high surface hardness by coating the paint mixed therein with flaky pigments having high hardness and additives for relieving said flaky pigments on the surface of a base material and allowing the paint to cure. CONSTITUTION:Flaky pigments having high hardness are generally glass flakes, and rigid aluminum foil powder, of which the Morse hardness is about >=5. Paper, synthetic resin sheets, plywood, etc. are used for the base material, and the additives that act to relieve the flaky pigments are generally wax and the like, surfactants, etc. If the paint mixed therein with the flaky pigments and the additives is coated on the surface of the base material, the flaky pigments are relieved on the top layer of the paint films, whereby the abrasion resistance of the paint films is improved. If the surface of the paint films is ground after curing of the paint, the surface hardness of the paint films is further improved. Thus the decorative material having the smooth surface which is hard to crack is obtained.
Patent•
07 Mar 1983
TL;DR: In this paper, an accurate determination of deterioration level in a Cr-Mo-V system heat resistant steel depending on the measurement of a replica image and hardness thereof after an oxygen etching of an extremely small part thereof by obtaining the distance between V4C3 particles and the hardness thereof while it is in use.
Abstract: PURPOSE:To enable an accurate determination of deterioration level in a Cr- Mo-V system heat resistant steel depending on the measurement of a replica image and hardness thereof after an oxygen etching of an extremely small part thereof by obtaining the distance between V4C3 particles and the hardness thereof while it is in use. CONSTITUTION:In the use of a Cr-Mo-V system heat resistant steel under a high temperature and a high stress, a coarse cohesion of V4C3 particles occurs in the steel with an increase in the time of application, causing the lowering of the hardness. Utilizing this, the base metal is melted by an oxygen etching of the surface of a molten steel in use and remaining V4C3 particles are shifted onto a replica. The replica is set on an electronic microscope and the closest distance between V4C3 particles is measured by a image processing utilizing an electronic computer to obtain the average thereof. On the other hand, the surface hardness is determined with a portable hardness meter or the like and converted into the Vickers hardness. The results thus obtained are compared to a predetermined relation diagram between the distance between V4C3 particles and the hardness to find the deterioration level of the steel accurately.
TL;DR: Hardness and ductility in Fe-M-B alloys were found to be directly dependent on the strength of the metal-metalloid bonding as discussed by the authors, which can be explained by the localized viscous flow model of heterogeneous deformation.
Abstract: Hardness and ductility in Fe-M-B alloys were found to be directly dependent on the strength of the metal-metalloid bonding. This behaviour, as well as the annealing embrittlement, can be explained by the localized viscous flow model of heterogeneous deformation.
TL;DR: In this paper, a theoretical model of the collapse process was developed to predict the extent of the developing plastic zones around the cross-section of the collapsing pipe and compared with the theoretical analysis.
Abstract: The standard hardness test result is dependent to some extent on the surface condition of the material being assessed. In particular, since the measurement involves permanent deformation of the surface the state of stress or strain in the material will influence the result. Consequently the hardness test may be used as an indicator of prior plastic deformation. The present investigation was concerned with the phenomenon of buckle propagation in undersea pipelines and a theoretical model of the collapse process was developed. The model predicted the extent of the developing plastic zones around the cross-section of the collapsing pipe. Hardness measurements on the cross-sections of collapsed pipe have been used to estimate the extent of the plastic zones and comparisons with the theoretical analysis are given.
TL;DR: In this paper, the relationship between the hardness and the compressive flow stress of the sintered metals in obtained using square-based pyramids is performed and it is shown that the ratio of the hardness to the flow stress is dependent upon the relative density.
Abstract: Indentation of sintered metals with square-based pyramids is performed and the relationship between the hardness and the compressive flow stress of the sintered metals in obtained. When the semi-angle α of the pyramid is 68°, which corresponds to the semi-angle of a Vickers hardness indenter, the ratio of the hardness to the flow stress is dependent upon the relative density. However, when α is 45°, the ratio is a constant value of 2.7 without influence of the relative density. Therefore, the flow stress of the sintered metals can be estimated from the hardness measured by using the indenter with the semi-angle of 45°.
TL;DR: In this paper, the effects of electron beam surface melting on a high strength Ni-Cr-Mo-V steel are first described with particular reference to the refined microstructure and the increased surface hardness.
Abstract: The effects of electron beam surface melting on a high strength Ni-Cr-Mo-V steel are first described with particular reference to the refined microstructure and the increased surface hardness. Similar experiments on an Fe80P13C7 alloy are described, in which surface amorphous layers were produced leading to hardnesses around 910VPN at the surface up to 1250VPN further in and falling to 650VPN in the as-cast crystalline substrate. Metallic glass cladding of the steel was achieved by coating the steel surface with thin layers of powdered Fe80P13C7 alloy, and traversing with an electron beam sufficient to fuse the powder layer. Process variables including beam power and thickness of powder layer were examined and optimum conditions for glass formation in the surface layer were determined. These layers were examined by optical and electron microscopy, X-ray diffractometry and energy dispersive X-ray analysis. The microhardness variation with distance from the surface was also determined and found to be in the range 880–1150VPN.