scholarly journals Crack Healing and Mechanical Properties Recovery in SA 508–3 Steel

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 890 ◽  
Author(s):  
Yao Qiu ◽  
Ruishan Xin ◽  
Jianbin Luo ◽  
Qingxian Ma
Keyword(s):  
Mechanical Properties ◽  
Low Cycle Fatigue ◽  
Optical Microscope ◽  
Reduction Ratio ◽  
Fatigue Properties ◽  
Crack Healing ◽  
Hot Plastic Deformation ◽  
Crack Zone ◽  
Healing Temperature ◽  
The Impact

Internal cracks could be healed under the process of hot plastic deformation. In this study, mechanical properties recovery after crack healing in SA 508–3 steel were investigated. Microstructures of the crack healing zones were observed using an optical microscope (OM) and electron back scattered diffraction (EBSD) technology, and the recovery degrees of mechanical properties in the crack healing zones with the healing temperature and a reduction ratio were tested systematically. The results showed that the internal cracks in SA 508–3 steel disappeared and were replaced by newly formed grains, achieved by recrystallization and abnormal grain growth. The tensile properties of crack healing zones could be fully restored, while their impact and low cycle fatigue properties could only be partially achieved. The recovery degrees of mechanical properties in crack healing zones increased with increasing the healing temperature and reduction ratio in the temperature range of 950–1050 °C. When the temperature was above 1150 °C, the impact properties began to deteriorate because of grain coarsening and larger MA (martensite–austenite) constituents. The microstructural evolution of the crack zone in the SA 508–3 steel was sketched.

Effect of Strain History on Steel Tube Umbilical

2007 ◽  
Author(s):  
Alan Dobson
Keyword(s):  
Mechanical Properties ◽  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Steel Tube ◽  
Fatigue Properties ◽  
Strain History ◽  
Stress Cracking ◽  
Induced Stress ◽  
The Impact ◽  
Strain Cycling

The effect of repeated plastic strain on the mechanical properties of reeled super duplex tube used in the construction of umbilical riser systems is assessed. The impact of typical plastic strain cycles on the fatigue properties of tubing, mechanical properties of the tubing and the susceptibility of hydrogen embrittlement of the tubing has been investigated. There is evidence that plastic strain cycles have an effect upon the fatigue life of the tube; which can be attributed to a low cycle fatigue mechanism. There is no evidence that plastic strain cycling to specified limits has an effect upon the susceptibility of the material to Hydrogen Induced Stress Cracking (HISC) and typical plastic strain cycles have no degenerative effect upon the mechanical properties of super duplex tube and radial welds.

Mechanical Properties of Equal-Channel Angular Extrusion-Processed Al-20Zn Alloy

2012 ◽  
Vol 445 ◽  
pp. 195-200
Author(s):  
Murat Aydin ◽  
Yakup Heyal
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Equal Channel Angular Extrusion ◽  
Considerable Change ◽  
Fatigue Properties ◽  
Dendritic Microstructure ◽  
Two Phase ◽  
Angular Extrusion ◽  
Alloy Increase ◽  
The Impact

The mechanical properties mainly tensile properties, impact toughness and high-cycle fatigue properties, of two-phase Al-20Zn alloy subjected to severe plastic deformation (SPD) via equal-channel angular extrusion (ECAE) using route A up to 2 passes were studied. The ECAE almost completely eliminated as-cast dendritic microstructure including casting defects such as micro porosities. A refined microstructure consisting of elongated micro constituents, α and α+η eutectic phases, formed after ECAE via route A. As a result of this microstructural change, mechanical properties mainly the impact toughness and fatigue performance of the as-cast Al-20Zn alloy increased significantly through the ECAE. The rates of increase in fatigue endurance limit are approximately 74 % after one pass and 89 % after two passes while the increase in impact toughness is 122 %. Also the yield and tensile strengths of the alloy increase with ECAE. However, no considerable change occurred in hardness and percentage elongation of the alloy. It was also observed that the ECAE changed the nature of the fatigue fracture characteristics of the as-cast Al-20Zn alloy.

scholarly journals Physico-Mechanical Properties of the Poly(oxymethylene) Composites Reinforced with Glass Fibers under Dynamical Loading

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2064 ◽  
Author(s):  
Stanisław Kuciel ◽  
Patrycja Bazan ◽  
Aneta Liber-Kneć ◽  
Aneta Gądek-Moszczak
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Fiber Diameter ◽  
Glass Fibers ◽  
Fiber Reinforced Composites ◽  
Dynamic Loads ◽  
Fatigue Properties ◽  
Reinforced Composites ◽  
The Impact ◽  
Microscopy Images

The paper evaluated the possibility of potential reinforcing of poly(oxymethylene) (POM) by glass fiber and the influence of fiberglass addition on mechanical properties under dynamic load. Four types of composites with glass fiber and another four with carbon fiber were produced. The fiber content ranged from 5% to 40% by weight. In the experimental part, the basic mechanical and fatigue properties of POM-based composites were determined. The impact of water absorption was also investigated. The influence of fiber geometry on the mechanical behavior of fiber-reinforced composites of various diameters was determined. To refer to the effects of reinforcement and determine the features of the structure scanning electron microscopy images were taken. The results showed that the addition of up to 10 wt %. fiberglass increases the tensile properties and impact strength more than twice, the ability to absorb energy also increases in relation to neat poly(oxymethylene). Fiber geometry also has a significant impact on the mechanical properties. The study of the mechanical properties at dynamic loads over time suggests that composites filled with a smaller fiber diameter have better fatigue properties.

Study on Weldablity of Dissimilar Steel between 16MnR and S31803

2011 ◽  
Vol 391-392 ◽  
pp. 768-772 ◽  
Author(s):  
Li Yang ◽  
Zhan Zhe Zhang
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Impact Toughness ◽  
Weld Metal ◽  
Welded Joint ◽  
Optical Microscope ◽  
Dissimilar Steel ◽  
Austenite Content ◽  
Mechanical Properties And Corrosion ◽  
The Impact

The weldablity of dissimilar steel between 16MnR and S31803 was analyzed and researched. By means of optical microscope (OM), the microstructure of the weld joint was investigated, which is welded by tungsten inert gas arc backing welding (GTAW) and manual arc filling welding (SMAW). The mechanical properties and corrosion resistance of the welded joint was also tested and studied. Results indicate that austenite and acicular ferrite distribute uniformly in the weld metal, which strengths the toughness and ductility of the joint. The austenite content in weld is higher than that in over-heated zone of S31803.The SMAW joint structure is coarsening than that of GTAW and has more austenite content. It is also observed that there are a decarburization layer and a carbon-enriched zone nearby the fusion line. And very small amounts of the third phase of harmful metal phase are found in the fusion zone of S31803 side. The welded joint shows the excellent mechanical properties and corrosion resistance. The impact toughness of the weld metal is higher than in HAZ of 16MnR side, and the impact toughness at GTAW side and in HAZ is superior to the SMAW side.

Effect of Re-Ti compound modification on the microstructure and mechanical properties of Cr12mov steel

2020 ◽  
pp. 002072091989756
Author(s):  
Sijing Fu ◽  
Binghua Jiang ◽  
Jing Wang ◽  
Hong Cheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Optical Microscope ◽  
Test Machine ◽  
Impact Tester ◽  
Near Net Shape ◽  
The Impact ◽  
Compound Modification ◽  
Ti Content

In this paper, near net shape casting technology was used to manufacture Cr12MoV steel die modified using RE-Ti. The samples with different RE(rare earth)-Ti content were fabricated by using the induction furnace. The microstructure of the samples was analyzed by using optical microscope and scanning electron microscope. Electronic universal tensile test machine, pendulum impact tester and rockwell apparatus were utilized to test the mechanical properties of the samples. The results show that after RE-Ti compound modification, the distribution and morphology of carbide are improved, and with the Ti increase, the impact toughness significantly increases, and tensile strength has a slight increase, but hardness is almost unchanged. When Ti content is 0.6%, the impact toughness and tensile strength are 14.9 J/cm2 and 634 MPa, respectively, reaching or approaching to the mechanical properties of the forged Cr12MoV steel.

The Effect of Morphology and Distribution of Sulfides on Mechanical Properties and Fatigue Life of Non-Quenched and Tempered Steel

2008 ◽  
Vol 51 ◽  
pp. 11-20
Author(s):  
Ming Tu Ma ◽  
Guo Zhong Li ◽  
Zhi Gang Li ◽  
Hong Zhou Lu
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Fracture ◽  
Rolling Direction ◽  
Impact Fracture ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Quenched And Tempered Steel ◽  
The Impact ◽  
Tempered Steel

The effect of morphology and distribution of sulfides on tensile, impact and bending fatigue properties of non-quenched and tempered steel 49MnVS3 has been investigated in this paper. Microscopic structure and morphology of sulfides are observed, and impact fracture and fatigue fracture have been analyzed by SEM. The results show that the morphology of sulfides is mostly strip and distributes in ferrite, which affects mechanical properties and fatigue life. The length direction of sulfide strip is parallel to the rolling direction of steel. When the length of sulfide is short relatively and is approximate to the shape of particles. The impact properties and bending fatigue performance of 49MnVS3 are higher. Under those conditions, there are more ductile characteristics in their impact fracture and the fatigue fracture. The reasons for the effect of sulfide morphology on the mechanical and fatigue properties are explained.

scholarly journals Methodological Aspects of Obtaining and Characterizing Composites Based on Biogenic Diatomaceous Silica and Epoxy Resins

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4607
Author(s):  
Marta Dobrosielska ◽  
Renata Dobrucka ◽  
Dariusz Brząkalski ◽  
Michał Gloc ◽  
Janusz Rębiś ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Epoxy Resins ◽  
Diatomaceous Earth ◽  
Optical Microscope ◽  
Filler Concentration ◽  
Large Area ◽  
Diatomaceous Silica ◽  
Guidelines And Recommendations ◽  
The Impact

Diatomaceous earth are sediments of unicellular algal skeletons with a well-defined hierarchical structure. Despite many tests conducted on systems using diatomaceous earth and epoxy resins, we can find many differences in the methods of acquisition and characteristics of the composite, which may considerably affect the results. In our study, we have conducted tests to verify the impact of the method of obtaining samples and the degassing of the composite on its mechanical properties and standard deviation. The samples were cast in glass moulds and silicone moulds and then subjected to testing for their mechanical and functional properties, imaging with the use of an optical microscope and a scanning electron microscope. The tests have shown that, for samples cast in glass moulds, there is no heterogeneity within the area of the tested sample, as in the case of samples cast in silicone moulds. Silicone moulds allow for quite effective self-degassing of the resin due to the large area-to-mass ratio, and the small remaining air vesicles have a limited effect on the mechanical properties of the samples. The filler used also played a significant role. For systems containing base and rinsed diatomite, it is clear that the degassing of mixtures increases the tensile strength. For treated diatomite, the elongation at break grew along with increasing filler concentration, while for base diatomite, the improvement was observed for flexural strength and impact strength. A non-modified epoxy resin shows a tensile strength at 19.91 MPa (silicone mould cast). At the same time, the degassed, glass mould-cast systems containing 12% of base and rinsed diatoms showed a tensile strength of 27.4 MPa and 44.7 MPa, respectively. We have also observed that the higher the filler concentration, the higher were the tensile strength values, which for the rinsed diatoms reached over 55.1 MPa and for the base diatoms were maximum of 43.8 MPa. The tests, therefore, constitute a set of guidelines and recommendations for testing with the use of fillers showing an extended inner structure.

scholarly journals INVESTIGATION OF HOT PLASTIC DEFORMATION OF LABORATORY AXIAL FLOATS

2021 ◽  
pp. 12-16
Author(s):  
Oleksandr Babachenko ◽  
Ganna Kononenko ◽  
Katerina Domina ◽  
Rostislav Podolskyi ◽  
Olena Safronova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Chemical Composition ◽  
Physical And Mechanical Properties ◽  
Pressure Treatment ◽  
Initial Length ◽  
Hot Plastic Deformation ◽  
The Impact ◽  
Further Development

A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.

scholarly journals Experimental Research on the Nanoindentation of Bovine Compact Bone under Fatigue Loading

2021 ◽  
Author(s):  
Xianjia Meng ◽  
Qinghua Qin ◽  
Chuanyong Qu
Keyword(s):  
Mechanical Properties ◽  
Fatigue Damage ◽  
Time Constant ◽  
Fatigue Loading ◽  
Compact Bone ◽  
Optical Microscope ◽  
Bone Fragility ◽  
Fatigue Properties ◽  
P Value ◽  
Reduced Modulus

Abstract Background The role of bone fatigue damage at the nanostructural level, and its effect on fatigue properties is an understudied and important subject. An understanding of the subtler aspects of bone’s properties is crucial to understanding bone fragility caused by aging, disease, and fatigue damage. The primary strength of this study was the demonstration of the degradation of bone’s microscopic mechanical properties by nanoindentation following fatigue loading. Methods Nanoindentation was used to probe the micro-mechanical properties of bovine tibiae subjected to fatigue loading in four-point bending. Indentation tests were conducted in the same 30×120 µm region before fatigue loading and after loading to fracture. We analysed the effects of residual indentations on bone’s fatigue resistance using an optical microscope and scanning electron microscope. The mechanical properties calculated using nanoindentation were reduced modulus and hardness, the time constant based on creep, long-term creep viscosity and the dissipated work. Differences of each parameter before loading and post fracture were examined using paired t-tests. Results The morphology of the initial residual indentation before fatigue loading appeared the same as that after loading to fracture. The results show that the reduced modulus decreased significantly (p = 9.47×10− 3) by 7.62%~15.16% after fracture whereas the time constant of creep increased slightly (p = 0.049) by 2.81%~5.41%. The p-value was significantly lower (p < 0.001) for reduced modulus compared to all other mechanical properties. Conclusion Residual indents different from fatigue damage created no crack initiators that would weaken bone’s resistance to fatigue loading. Fatigue loading has the most heavy effect on bone’s reduced modulus compared to all other microscopic mechanical properties.

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