MECHANICAL PROPERTIES OF HEAT-STRENGTHENED STEEL 65G SURFACE-REINFORCED WITH HARD-ALLOY SURFACING

2021 ◽  
pp. 63-68
Author(s):  
ALEKSANDR M. MIKHALCHENKOV ◽  
◽  
NATALIA D. ULYANOVA ◽  
SERGEY A. FESKOV ◽  
ALEKSANDR A. GUTSAN ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Abrasive Particle ◽  
High Hardness ◽  
Abrasive Medium ◽  
Leaf Springs ◽  
Heat Treated ◽  
Repair Materials ◽  
Heat Hardening ◽  
Surface Reinforcement

Increasing the service life of soil-cultivating equipment parts by the use of surfacing reinforcement of working surfaces has found a fairly wide application. However, the studies carried out on this problem were focused on parts, the metal of which had not been subjected to preliminary heat hardening. Meanwhile, in recent years, the components of the working tools of agricultural implements are almost completely hardened by heat treatment. This is especially true for imported products. Information on the reinforcement of parts that have undergone this kind of processing is extremely scarce, and sometimes contradictory. Therefore, the research task was to study the properties of heat-strengthened steel 65G after its surface reinforcement. During the experiments, as the base metal, use was made of spring sheets made of 65G steel with a hardness of about 45 HRC. T-590 electrodes were used as the surfacing material, intended for surfacing of parts operated in an abrasive environment. The reliability of the results obtained was guaranteed by a large number of measurements. Mechanical properties were evaluated by HRC hardness. As a result of experiments, it was found that the hardness value of 44…47 HRC for leaf springs taken out of service makes them suitable for use as repair materials. When surfacing one roller, the initial hardness of the base metal remains at the same level; surfacing two rollers leads to a decrease in HRC by 9 units. Three zones are distinguished in the area between the rollers. The use of reinforcing rollers on the surface of heat-treated steel 65G increases its service properties due to their high hardness, a decreased contact path of the abrasive particle with the working surface and forms a “fl uidized” layer of a moving abrasive medium between the rollers.

scholarly journals Microstructure and Mechanical Properties of Intercritically Treated Grade 91 Steel

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3985
Author(s):  
Yiyu Wang ◽  
Wei Zhang ◽  
Yong Chae Lim ◽  
Yanli Wang ◽  
Zhili Feng
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Degradation Mechanism ◽  
Local Strain ◽  
Critical Temperatures ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated ◽  
Hardness Increase ◽  
Grade 91 ◽  
Grade 91 Steel

Premature creep failures at the intercritical heat affected zone (ICHAZ) of creep-resistant steel weldments have been frequently reported. However, the creep degradation mechanism of different microstructure constituents in ICHAZ is complicated and needs further clarification. In this work, Grade 91 steel was intercritically heat-treated at a temperature (860 °C) between the critical temperatures AC1 and AC3, and a correlation between microstructure and mechanical properties of the heat-treated specimen was built. The effects of austenitization and tempering resulting from the intercritical treatment (IT) differentiated the local strain energies between the two microstructure constituents: newly transformed martensite (NTM) and over-tempered martensite (OTM). The formation of NTM grains led to a hardness increase from 247 HV0.5 in the base metal to 332 HV0.5 in the IT specimen. The ultimate tensile strength (UTS) increased from 739 MPa in the base metal to 1054 MPa in the IT specimen. Extensive growth of the OTM grains and rapid recovery of NTM grains took place simultaneously in the IT specimen during a typical tempering at 760 °C. These microstructure degradations led to a lowered hardness of 178 HV0.5, a reduced UTS of 596 MPa, and a poor creep resistance with a minimum creep strain rate of 0.49 %/h at 650 °C in an IT + tempering (ITT) specimen.

Effects of particulate reinforcements on the hardness, impact and tensile strengths of AA 6061-T6 friction stir weldments

2021 ◽  
pp. 146442072199554
Author(s):  
TE Abioye ◽  
H Zuhailawati ◽  
AS Anasyida ◽  
SP Ayodeji ◽  
PK Oke
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Base Metal ◽  
Welded Joint ◽  
High Hardness ◽  
Friction Stir ◽  
Heat Treated ◽  
Impact Energies ◽  
The Impact ◽  
Metal Hardness

Due to loss of structural strengthening at temperatures beyond 250°C, heat-treated aluminium alloys (e.g. AA 6061-T6) weldments are usually characterized with poor mechanical properties including hardness, tensile and impact strengths. In this work, friction stir weldments of AA 6061-T6 reinforced with the additions of SiC, B4C and Al2O3 particles at the joints were produced and investigated for improved hardness, tensile strength and impact strength over the unreinforced weldment. The results showed that the entire reinforced welded joint exhibited improved hardness because of the enhanced metal matrix grain refinement and inherent high hardness of the reinforcement particles. B4C particle addition produced hardest joint of about 81% of the base metal hardness (∼114 HV0.3). The impact energies of the SiC (16.9 J), B4C (16.5) and Al2O3 (12.2 J) reinforced weldments are closer to that of the base metal (18.6 J) compared with the unreinforced weldment (9.6 J). The reinforced weldments showed no significant improvement over the tensile strength of the unreinforced weldment. B4C and SiC reinforcements produced the highest improvements in the hardness (at the joint) and impact strength of the AA 6061-T6 friction stir weldments, respectively.

scholarly journals Role of supersaturated Al-C phases in mechanical properties of Al/fullerene composites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seungjin Nam ◽  
Sooun Lee ◽  
Aeran Roh ◽  
Hansol Son ◽  
Miso Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Elastic Modulus ◽  
High Hardness ◽  
Treatment Temperature ◽  
Acoustic Microscopy ◽  
Atomic Scale ◽  
Plastic Behavior ◽  
Large Contribution ◽  
Heat Treated

AbstractWe investigated the reinforcing effect of supersaturated Al-C phases on the mechanical properties of Al/C60 composites produced via powder metallurgy followed by thermal treatment. We controlled the fractions of C60-fullerenes, nano-scale carbides, and Al-C supersaturated phases in the Al/C60 composites by adjusting the heat-treatment temperature and duration. Furthermore, we examined the contribution of each phase on the elastic and plastic behavior of the composites using scanning acoustic microscopy (SAM) and hardness measurements. After heat treatment, a supersaturated Al-C phase and an Al carbide were formed in the Al/C composites by decomposition of individually dispersed C60. This led to enhancement of the hardness and elastic modulus of the Al/C composites heat-treated at 450 and 500 °C, while these properties were reduced in the 650 °C heat-treated composite. Notably, the 500 °C heat-treated composites showed significantly high hardness and elastic modulus (approximately 250 Hv and 77.8 GPa, respectively) owing to the substantially large contribution of the supersaturated Al-C phases, which was theoretically calculated to be 851 GPa/vol% and 227 GPa/vol%, respectively. This is possibly because the well-dispersed C in the atomic scale changed the elastic bonding characteristics of the metallic bonds between the Al atoms.

scholarly journals Tensile Strength, Micro-hardness and Microstructure of Friction-Stir-Welding AA6061-T4 Joints

2018 ◽  
Vol 25 (4) ◽  
pp. 50-55
Author(s):  
Najeeb S. Abtan ◽  
Ataalah Hussain Jassim ◽  
Mustafa S. M. Al-Janabi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Base Metal ◽  
High Hardness ◽  
Welding Parameters ◽  
Micro Hardness ◽  
Friction Stir ◽  
Wide Range

Welding of aluminum alloys by traditional welding methods creates some defects such as hot cracks, porosity, and void that led to decreasing of mechanical properties. Friction Stir Welding (FSW) gives good mechanical properties of aluminum alloy welds. In this paper, FSW worked in 4 mm thick plate of 6061-T4 aluminum alloy, with two welding parameters are used (tool rotational speed and feed rate) was investigated, were analyzed the microstructure and mechanical properties by carried out microstructural, micro-hardness, and tensile strength tests. From results are found defect-free of welds at a wide range of parameters. Stir zone shows a fine-equiaxed grain and high hardness, not significantly change between heat affected zone and base metal in size grain. Tensile strength of welds was lower than base metal and fracture location was occurred at a low hardness region for the welds.

Crystallographic Differences of Metastable NI2MO in a NI-MO-AL Superalloy

1980 ◽  
Vol 38 ◽  
pp. 158-159
Author(s):  
Michael M. Kersker ◽  
E. A. Aigeltinger ◽  
J. J. IIren
Keyword(s):  
Mechanical Properties ◽  
Air Cooling ◽  
Solution Treated ◽  
Heat Treated ◽  
Metastable Compounds ◽  
Rapidly Solidified

Ni-rich alloys based on approximate ternary composition Ni-8Mo-15A1 (at%) are presently under investigation in an attempt to study the contribution, if any, of the profusion of Mo-rich NixMo metastable compounds that these alloys contain to their excellent mechanical properties. One of the alloys containing metastable NixMo precipitates is RSR 197 of composition Ni-8.96Mo-15.06A1-1.98Ta-.015Yt. The alloy was prepared at Pratt and Whitney Government Products Division, West Palm Beach, Florida, from rapidly solidified powder. The powder was canned under inert conditions and extruded as rod at 1315°C. The as-extruded rod, after air cooling, was solution treated at 1315°C for two hours, air cooled, and heat treated for one hour at 815°C, followed again by air cooling.

REYNOLDS 390 and A390

Alloy Digest ◽  
1971 ◽  
Vol 20 (8) ◽  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
High Hardness ◽  
Heat Treating ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Temperature Performance

Abstract REYNOLDS 390 and A390 are hypereutectic aluminum-silicon alloys having excellent wear resistance coupled with good mechanical properties, high hardness, and low coefficients of expansion. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, and machining. Filing Code: Al-203. Producer or source: Reynolds Metals Company.

scholarly journals Analysis of the Microstructure and Mechanical Properties of TiBw/Ti-6Al-4V Ti Matrix Composite Joint Fabricated Using TiCuNiZr Amorphous Brazing Filler Metal

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 875
Author(s):  
Hao Tian ◽  
Jianchao He ◽  
Jinbao Hou ◽  
Yanlong Lv
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Matrix Composite ◽  
Room Temperature ◽  
Filler Metal ◽  
Ceramic Fiber ◽  
Tensile Fracture ◽  
Alloy Matrix ◽  
Composite Joint ◽  
Secondary Cracks

TiB crystal whiskers (TiBw) can be synthesized in situ in Ti alloy matrix through powder metallurgy for the preparation of a new type of ceramic fiber-reinforced Ti matrix composite (TMC) TiBw/Ti-6Al-4V. In the TiBw/Ti-6Al-4V TMC, the reinforced phase/matrix interface is clean and has superior comprehensive mechanical properties, but its machinability is degraded. Hence, the bonding of reliable materials is important. To further optimize the TiBw/Ti-6Al-4V brazing technology and determine the relationship between the microstructure and tensile property of the brazed joint, results demonstrate that the elements of brazing filler metal are under sufficient and uniform diffusion, the microstructure is the typical Widmanstätten structure, and fine granular compounds in β phase are observed. The average tensile strength of the brazing specimen is 998 MPa under room temperature, which is 97.3% of that of the base metal. During the high-temperature (400 °C) tensile process, a fracture occurred at the base metal of the highest tensile test specimen with strength reaching 689 MPa, and the tensile fracture involved a combination of intergranular and transgranular modes at both room temperature and 400 °C. The fracture surface has dimples, secondary cracks are generated by the fracture of TiB whiskers, and large holes form when whole TiB whiskers are removed. The proposed algorithm provides evidence for promoting the application of TiBw/Ti-6Al-4V TMCs in practical production.

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

scholarly journals Temperature-Dependent Creep Behavior and Quasi-Static Mechanical Properties of Heat-Treated Wood

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 968
Author(s):  
Dong Xing ◽  
Xinzhou Wang ◽  
Siqun Wang
Keyword(s):  
Mechanical Properties ◽  
Creep Behavior ◽  
Cell Walls ◽  
Treated Wood ◽  
Crosslinking Reaction ◽  
Depth Sensing ◽  
Temperature Dependent ◽  
Heat Treated ◽  
Static Mechanical ◽  
Static Mechanical Properties

In this paper, Berkovich depth-sensing indentation has been used to study the effects of the temperature-dependent quasi-static mechanical properties and creep deformation of heat-treated wood at temperatures from 20 °C to 180 °C. The characteristics of the load–depth curve, creep strain rate, creep compliance, and creep stress exponent of heat-treated wood are evaluated. The results showed that high temperature heat treatment improved the hardness of wood cell walls and reduced the creep rate of wood cell walls. This is mainly due to the improvement of the crystallinity of the cellulose, and the recondensation and crosslinking reaction of the lignocellulose structure. The Burgers model is well fitted to study the creep behavior of heat-treated wood cell walls under different temperatures.

Sign in / Sign up

Export Citation Format

Share Document