scholarly journals Developing definitions of conventional hardness tests for use by National Metrology Institutes

2021 ◽  
Vol 18 ◽  
pp. 100096
Author(s):  
S. Low ◽  
A. Germak ◽  
A. Knott ◽  
R. Machado ◽  
J. Song
Keyword(s):  
National Metrology Institutes ◽  
Hardness Tests

Analisis Kegagalan Boom Crane dan Pencegahannya

2014 ◽  
Vol 10 (1) ◽  
pp. 19
Author(s):  
Elvis Adril ◽  
Nasirwan - ◽  
Tri Wibowo ◽  
Julnaidi -
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Chemical Composition ◽  
Optimum Design ◽  
Root Cause ◽  
Main Equipment ◽  
Hardness Tests ◽  
Photo Documentation ◽  
Crawler Crane ◽  
Boom Crane

Sleeve (Boom) on Crawler Crane is the main equipment that serves the weight at the time of appointment (Hoisting).The problem which is founded is a fracture at the boom while lift 6 Tons of weight while the optimum design of equipment is 50 tons. The aim of this research is to found the root cause of the fracture by using photo documentation fractografi (microfractografi and macrofractografi), and hardness tests, and test the chemical composition at the surface faults boom crane. We used Finite element method (FEM) to form simulated load. The results is that the porblem accured because of error while read the load chart and error in SOP

Influence of Melt Temperature on Compressive Plasticity of a Cu-Zr-Al Bulk Metallic Glass

2010 ◽  
Vol 146-147 ◽  
pp. 517-521
Author(s):  
Sheng Hui Xie ◽  
Xie Rong Zeng ◽  
Dong Ju Fu ◽  
Lei Zhao ◽  
Qiang Hu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Metallic Glasses ◽  
Mechanical Performance ◽  
Casting Temperature ◽  
Thermal And Mechanical Properties ◽  
Micro Hardness ◽  
Melt Temperature ◽  
Hardness Tests ◽  
Important Solution

Cu47.5Zr47.5Al5 bulk metallic glasses (BMGs) were cast from the melt temperature 1143 to 1373 K. The structure, thermal and mechanical properties of the BMGs were investigated by XRD, DSC, HRTEM, dilatometric measurements, micro-hardness tests and uniaxial compression. The results indicate that the microstructure and mechanical performance of BMGs are closely affected by the casting temperature. Proper casting temperature ensures the BMGs with large relaxed excess free volume (REFV) and nano-crystallites, which favor the plastic deformation in Cu47.5Zr47.5Al5 BMGs. Regulating the preparing parameters is an important solution to good plasticity in BMGs.

A Study of Microindentation Hardness Tests by Mechanism-based Strain Gradient Plasticity

2000 ◽  
Vol 15 (8) ◽  
pp. 1786-1796 ◽  
Author(s):  
Y. Huang ◽  
Z. Xue ◽  
H. Gao ◽  
W. D. Nix ◽  
Z. C. Xia
Keyword(s):  
Strain Gradient ◽  
Size Dependence ◽  
Plasticity Theory ◽  
Strain Gradient Plasticity ◽  
Gradient Plasticity ◽  
Hierarchical Framework ◽  
Microindentation Hardness ◽  
Dislocation Hardening ◽  
Hardness Tests ◽  
Micro Indentation

We recently proposed a theory of mechanism-based strain gradient (MSG) plasticity to account for the size dependence of plastic deformation at micron- and submicronlength scales. The MSG plasticity theory connects micron-scale plasticity to dislocation theories via a multiscale, hierarchical framework linking Taylor's dislocation hardening model to strain gradient plasticity. Here we show that the theory of MSG plasticity, when used to study micro-indentation, indeed reproduces the linear dependence observed in experiments, thus providing an important self-consistent check of the theory. The effects of pileup, sink-in, and the radius of indenter tip have been taken into account in the indentation model. In accomplishing this objective, we have generalized the MSG plasticity theory to include the elastic deformation in the hierarchical framework.

Influence of Microstructural Change on Damping Capacity of Mg-X%Li Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 1764-1768
Author(s):  
Joong Hwan Jun ◽  
Ki Duk Seong ◽  
Jeong Min Kim ◽  
Ki Tae Kim ◽  
Woon Jae Jung
Keyword(s):  
Single Phase ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Microstructural Change ◽  
Damping Capacity ◽  
Flexural Mode ◽  
X Ray ◽  
Α Phase ◽  
Hardness Tests ◽  
Li Content

The Effects of Li content and annealing treatment on microstructure and damping capacity for Mg-X%Li alloys have been investigated, based on experimental results from X-ray diffractometry (XRD), optical microscopy (OM), hardness tests and vibration damping tests in a flexural mode. The Mg-X%Li alloys containing Li of 3%, 8% and 13% consist of α (HCP) single phase, (α + β (BCC)) dual phases and β single phase, respectively. In as-rolled state, the damping capacity for Mg-Li alloys shows a similar level regardless of Li content. The annealing treatments at 200oC and 400οC give rise to an enhancement of damping capacity only for the Mg-3%Li and Mg-8%Li alloys containing α phase, and at the same annealing temperature, the Mg-3%Li alloy with fully α structure exhibits higher damping capacity. This result indicates that the damping capacity of Mg-Li alloys depends principally on α phase, and that the annealing treatment is necessary to improve its damping capacity.

Using Hardness Tests to Quantify Bulk Plasticity and Predict Transition Velocities in SiC Materials

2012 ◽  
Vol 10 (1) ◽  
pp. 114-122 ◽  
Author(s):  
Corydon D. Hilton ◽  
James W. McCauley ◽  
Jeffrey J. Swab ◽  
Eugene R. Shanholtz ◽  
Ming W. Chen
Keyword(s):  
Hardness Tests

scholarly journals Friction Stir Welding of AA2024-T3 plate – the influence of different pin types

2015 ◽  
Vol 6 (1) ◽  
pp. 51-55 ◽  
Author(s):  
D. Trimble ◽  
H. Mitrogiannopoulos ◽  
G. E. O'Donnell ◽  
S. McFadden
Keyword(s):  
Friction Stir Welding ◽  
Parent Material ◽  
Micro Hardness ◽  
Workpiece Material ◽  
Friction Stir ◽  
Hardness Tests ◽  
Weld Profile ◽  
Unaffected Parent ◽  
Line Defects ◽  
Tool Pin

Abstract. Some aluminium alloys are difficult to join using traditional fusion (melting and solidification) welding techniques. Friction Stir Welding (FSW) is a solid-state welding technique that can join two plates of material without melting the workpiece material. This proecess uses a rotating tool to create the joint and it can be applied to alumium alloys in particular. Macrostructure, microstructure and micro hardness of friction stir welded AA2024-T3 joints were studied. The influence of tool pin profile on the microstructure and hardness of these joints was examined. Square, triflute and tapered cylinder pins were used and results from each weldment are reported. Vickers micro hardness tests and grain size measurements were taken from the transverse plane of welded samples. Distinct zones in the macrostructure were evident. The zones were identified by transitions in the microstructure and hardness of weld samples. The zones identified across the sample were the the unaffected parent metal, the Heat Affected Zone (HAZ), the Thermo-Mechanicaly Affected Zone (TMAZ), and the Nugget Zone (NZ). Measured hardness values varied through each FSW zone. The hardness in each zone was below that of the parent material. The HAZ had the lowest hardness across the weld profile for each pin type tested. The cylindrical pin consistently produced tunnel and joint-line defects. Pin profiles with flat surface features and/or flutes produced consolidated joints with no defects.

scholarly journals Tribological Performance of CoCrMo Alloys with Boron Additions in As-Cast and Heat-Treated Conditions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 355
Author(s):  
Marco A. L. Hernandez-Rodriguez ◽  
Diego E. Lozano ◽  
Gabriela M. Martinez-Cazares ◽  
Yaneth Bedolla-Gil
Keyword(s):  
Boron Content ◽  
Tribological Performance ◽  
Secondary Phases ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Hardness Tests ◽  
Heat Treated ◽  
Cocrmo Alloys ◽  
Cast Condition ◽  
Ball On Disc

The present study evaluates the effect of boron additions on the tribological performance of CoCrMo alloys. The alloys were prepared with boron ranging from 0.06 to 1 wt%. The materials were characterized using metallographic techniques, scanning electronic microscopy, and roughness and hardness tests. Tribological evaluation was made by means of ball-on-disc tests for sliding distances of 4, 8 and 12 km. The samples were in the as-cast condition and after a heat treatment at 1200 °C for 1 h, finished by water quenching. The results showed that wear resistance was influenced by the microstructure and the number of secondary phases. The volume loss decreased as the boron content increased. Due to hard phases, abrasion wear was observed. Delamination fatigue was also detected after long sliding distances. Both wear mechanisms diminished in higher boron content alloys.

A comparison of traceable spatial angle autocollimator calibrations performed by PTB and VTT MIKES

Metrologia ◽  
2021 ◽  
Author(s):  
Ralf D Geckeler ◽  
Matthias Schumann ◽  
Andreas Just ◽  
Michael Krause ◽  
Antti Lassila ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Measurement Errors ◽  
Systematic Measurement ◽  
Motivating Factors ◽  
Optical Surface ◽  
Transfer Standard ◽  
Surface Normal ◽  
National Metrology Institutes ◽  
Wide Range ◽  
The Creation

Abstract Autocollimators are versatile devices for angle metrology used in a wide range of applications in engineering and manufacturing. A modern electronic autocollimator generally features two measuring axes and can thus fully determine the surface normal of an optical surface relative to it in space. Until recently, however, the calibration capabilities of the national metrology institutes were limited to plane angles. Although it was possible to calibrate both measuring axes independently of each other, it was not feasible to determine their crosstalk if angular deflections were present in both axes simultaneously. To expand autocollimator calibrations from plane angles to spatial angles, PTB and VTT MIKES have created dedicated calibration devices which are based on different measurement principles and accomplish the task of measurand traceability in different ways. Comparing calibrations of a transfer standard makes it possible to detect systematic measurement errors of the two devices and to evaluate the validity of their uncertainty budgets. The importance of measurand traceability via calibration for a broad spectrum of autocollimator applications is one of the motivating factors behind the creation of both devices and for this comparison of the calibration capabilities of the two national metrology institutes. The latter is the focus of the work presented here.

Effect of Thermomechanical Rolling of the Induction Hardenability of a Micro-Alloyed 1045 Steel

2021 ◽  
Author(s):  
Robert Cryderman ◽  
Finn Bamrud
Keyword(s):  
Heating Temperature ◽  
Rapid Heating ◽  
Case Hardening ◽  
Single Shot ◽  
Austenite Grain Size ◽  
Hardness Tests ◽  
Thermomechanical Rolling ◽  
Lower Temperature ◽  
1045 Steel ◽  
Cct Diagrams

Abstract A micro-alloyed 1045 steel was commercially rolled into 54 mm diameter bars by conventional hot rolling at 1000 °C and by lower temperature thermomechanical rolling at 800 °C. The lower rolling temperature refined the ferrite-pearlite microstructure and influenced the microstructural response to rapid heating at 200 °C·s-1, a rate that is commonly encountered during single shot induction heating for case hardening. Specimens of both materials were rapidly heated to increasing temperatures in a dilatometer to determine the Ac1 and Ac3 transformation temperatures. Microscopy was used to characterize the dissolution of ferrite and cementite. Continuous cooling transformation (CCT) diagrams were developed for rapid austenitizing temperatures 25 °C above the Ac3 determined by dilatometry. Dilatometry and microstructure evaluation along with hardness tests showed that thermomechanical rolling reduced the austenite grain size and lowered the heating temperature needed to dissolve the ferrite. With complete austenitization at 25 °C above the Ac3 there was little effect on the CCT behavior.

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