Increase of Weld Joint Efficiency of the Combined Band of a High-Speed Rotor of an Electric Machine by Local Strengthening

2020 ◽  
Vol 299 ◽  
pp. 370-375
Author(s):  
Egor V. Terentyev ◽  
Artem Yu. Marchenkov ◽  
Andrey P. Sliva
Keyword(s):  
Heat Treatment ◽  
Tensile Stress ◽  
Weld Metal ◽  
High Speed ◽  
Electron Beam Welding ◽  
Ultimate Tensile Stress ◽  
Electric Machine ◽  
Weld Width ◽  
Weld Joints ◽  
36Nkhtyu Alloy

The research shows the possibility of increasing the structural strength of the weld joints of EP517 steel and 36NKhTYu iron-nickel alloy as applied to the combined bandage of the high-speed rotor of an electric machine, due to the effect of local strengthening of the soft interlayer. The technology of electron-beam welding of 36NKhTYu alloy to EP517 steel with free root formation, which allows to obtain narrow welds, is described. The results of metallographic researches and mechanical tests of weld joints with different weld widths are presented, which showed that the structure and properties of the weld metal on samples with different weld widths are almost identical. The tension test results of weld joints demonstrate a significantly greater ultimate tensile stress, compared to the ultimate tensile stress of the weld metal. Also, it was established that, due to the local strengthening phenomena the smaller the weld width, the stronger the welded joint is. In addition, the use of heat treatment after welding allows us to increase the strength properties of the weld metal and the heat-affected zone of the 36NKhTYu alloy, due to the formation of the hardening γ’-phase. The possibility of increasing the ultimate tensile strength of the weld up to 98% of the ultimate tensile stress value of EP517 steel (as the less durable of both welded materials), due to heat treatment and reducing the weld width, is demonstrated.

Investigation of Functionally Graded Aluminium A356 Alloy and A356-10%SiCp Composite for Hydro Turbine Bucket Application

2016 ◽  
Vol 26 ◽  
pp. 30-46 ◽  
Author(s):  
Williams S. Ebhota ◽  
Akhil S. Karun ◽  
Freddie L. Inambao
Keyword(s):  
Heat Treatment ◽  
Tensile Stress ◽  
Centrifugal Casting ◽  
A356 Alloy ◽  
Casting Process ◽  
Ultimate Tensile Stress ◽  
Functionally Graded ◽  
Cnc Machining ◽  
Mould Material ◽  
Turbine Bucket

The study investigates the application of centrifugal casting process in the production of a complex shape component, Pelton turbine bucket. The bucket materials examined were functionally graded aluminium A356 alloy and A356-10%SiCp composite. A permanent mould for the casting of the bucket was designed with a Solidworks software and fabricated by the combination of CNC machining and welding. Oil hardening non-shrinking die steel (OHNS) was chosen for the mould material. The OHNS was heat treated and a hardness of 432 BHN was obtained. The mould was put into use, the buckets of A356 Alloy and A356-10%SiCp composite were cast, cut and machined into specimens. Some of the specimens were given T6 heat treatment and the specimens were prepared according to the designed investigations. The micrographs of A356-10%SiCp composite shows more concentration of SiCp particles at the inner periphery of the bucket. The maximum hardness of As-Cast A356 and A356-10%SiCp composite were 60 BRN and 95BRN respectively, recorded at the inner periphery of the bucket. And these values appreciated to 98BRN and 122BRN for A356 alloy and A356-10%SiCp composite respectively after heat treatment. The prediction curves of the ultimate tensile stress and yield tensile stress show the same trend as the hardness curves.

scholarly journals Heat treatment mode optimization of dissimilar weld joints of EP517 steel to 36NKhTYu alloy

2020 ◽  
Vol 759 ◽  
pp. 012024
Author(s):  
E V Terentyev ◽  
A Yu Marchenkov ◽  
A L Goncharov ◽  
A P Sliva ◽  
K T Borodavkina
Keyword(s):  
Heat Treatment ◽  
Treatment Mode ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
Heat Treatment Mode ◽  
36Nkhtyu Alloy

Evaluation of Local Tensile Properties of Bi-Metallic Weld Joints by Small Tensile and Ball Indentation Tests

2007 ◽  
Vol 353-358 ◽  
pp. 2073-2076
Author(s):  
Jin Won Kim ◽  
Jong Sun Park ◽  
Jong Sung Kim ◽  
Tae Eun Jin
Keyword(s):  
Weld Metal ◽  
Tensile Properties ◽  
Ferritic Steel ◽  
Indentation Test ◽  
Ultimate Tensile Stress ◽  
Base Metals ◽  
Weld Joints ◽  
Ball Indentation ◽  
Indentation Tests ◽  
Ball Indentation Test

This study performed tensile test using small-size flat specimen and ball indentation test at room temperature to characterize the local tensile properties of bi-metallic weld joints. The weld specimens used were fabricated by joining between SA508 Gr.3 ferritic steel and Type 316 stainless steel with Alloy 82 buttering on the ferritic steel side and Alloy 82/182 weld metal. The test results showed that yield stress (YS) of weld metal was slightly higher than that of Type 316 and smaller than that of SA508 Gr.3, and ultimate tensile stress (UTS) of weld metal was similar as those of Type 316 and SA508 Gr.3 base metals. Also, the values of YS and UTS of buttering layer (Alloy 82) were nearly same as those of weld metal. Heat-affected-zones (HAZs) showed higher YS and UTS values compared to their base metals. Especially, the strengths of SA508 Gr.3 were significantly higher than those of surrounding materials. Also, it was known that the ball indentation test reasonably measured the local YS and UTS of bi-metallic weld joints.

The effect of heat treatment on mechanical properties of 42CrMo4 steel

2020 ◽  
Vol 1 (98) ◽  
pp. 5-10
Author(s):  
A. Çalık ◽  
O. Dokuzlar ◽  
N. Uçar
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Stress ◽  
Yield Stress ◽  
Impact Energy ◽  
Ultimate Tensile Stress ◽  
Tempering Temperature ◽  
Heat Treated ◽  
Quenching Process ◽  
42Crmo4 Steel

Purpose: In this study, the effect of heat treatment on the microstructure and mechanical properties of 42CrMo4 steel were investigated. Design/methodology/approach: The samples were annealed at 860°C for 120 min. followed by oil quenching and then tempered at temperatures between 480 and 570°C for 120 min. The microstructure of untreated 42CrMo4 steel mainly consists of pearlite and ferrite whereas the microstructure was found to be as a martensitic structure with a quenching process. Findings: The results showed that there is an increase in yield stress, ultimate tensile stress, hardness and impact energy, while elongation decreases at the end of the quenching process. Conversely, yield stress, ultimate tensile stress and hardness decrease slightly with the increasing of tempering temperature, while elongation and impact energy increase. Research limitations/implications: Other types of steels can be heat treated in a wider temperature range and the results can be compared. Practical implications: It is a highly effective method for improving the mechanical properties of heat treatment materials. Originality/value: A relationship between the mechanical properties and the microstructure of materials can be developed. The heat treatment is an effective method for this process.

Post-weld Heat Treatment and Groove Angles Affect the Mechanical Properties of T92/Super 304H Dissimilar Steel Weld Joints

2018 ◽  
Vol 37 (7) ◽  
pp. 649-654 ◽  
Author(s):  
Wang Shuo ◽  
Wei Limin ◽  
Cheng Yi ◽  
Tan Shuping
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Metal ◽  
Arc Welding ◽  
Post Weld Heat Treatment ◽  
Steel Weld ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
Gas Tungsten Arc ◽  
Weld Heat

AbstractThe microstructures and mechanical properties of dissimilar weld joints between T92 and Super 304H steels were investigated. Dissimilar weld joints with four groove angles were constructed using gas tungsten arc welding. The results showed that post-weld heat treatment improved the mechanical properties of the dissimilar weld joints. The optimal groove angle for T92/Super 304H dissimilar weld joints was found to be 20°, considering mechanical properties. Furthermore, the transformation from equiaxed dendrites to columnar dendrites was observed in the weld metal. Epitaxial growth and delta ferrites were found around the fusion line between the Super 304H and the weld metal.

The Causes of Low Impact Strength of T23 Steel Weld Joints

2015 ◽  
Vol 226 ◽  
pp. 103-106
Author(s):  
Janusz Adamiec ◽  
Izabela Pikos ◽  
Michał Stopyra
Keyword(s):  
Heat Treatment ◽  
Impact Strength ◽  
Weld Metal ◽  
Post Weld Heat Treatment ◽  
Weld Joints ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
The Impact ◽  
Welding Technique ◽  
Weld Heat

T23 is modern bainitic steel designed for use in supercritical boilers. According to producer’s data weldability of this steel is good enough to avoid post-weld heat treatment. However, some of the T23 weld joints in as-welded condition have not met the minimal ductility requirement. The impact test revealed significant differences between the joints in as-welded and heat treated condition. Metallographic and fractographic examinations have been conducted in order to explain those differences. The specimens with low impact strength were characterized by brittle fracture and non-tempered martensite presence in weld metal. It was concluded that avoiding formation of disadvantageous structure in weld metal requires conducting of post weld heat treatment or applying multi-pass welding technique with annealing run.

scholarly journals The Effect of Cast Iron Preheating on the Microstructure of Welding Results by Using Cin-2 Electrodes

Teknomekanik ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 50-55
Author(s):  
Ahmad Sabirin ◽  
Purwantono Purwantono
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Weld Metal ◽  
Arc Welding ◽  
Shielded Metal Arc Welding ◽  
Affected Area ◽  
Weld Joints ◽  
Microstructure Observation ◽  
Metal Arc Welding ◽  
The One

Cast iron is commonly found in engineering tools such as machine frames, vise, lathes, planers, pressing tools, V-belt pulleys and others. Cast iron is a metal which is relatively difficult to weld because it contains more than 0.3% carbon. As a matter of fact, a lot of welding workers still experience failure in welding the cast iron, so they require the proper procedures to perform welding on the cast iron like the heat treatment before the welding. This study was aimed at obtaining the effect of preheating variations on the weld joints in which the process of welding the material used the type of open V seam connection. The specimen used was a cast iron with a thickness of 10 mm and the electrode used was the JIS Z 3252 DFCNiFe electrode. The method applied in this research was the microstructure observation testing toward the welding result by using Shielded Metal Arc Welding (SMAW). Based on the results of the study, it can be concluded that by applying the preheating variation treatment on the cast iron welding, there was a change in the microstructure and it was dominated by pearlite-ferrite in the weld metal area. As a result, the rough graphite that looks like roots became smooth after experiencing the preheating treatment because the ferrite was evenly distributed in the heat affected area. To conclude, the most superior specimen for the cast iron preheating among the four specimens was the one with 425oC temperature.

Analysis of Microstructure Abnormal of P91 in Water Storage Tank of Super-Critical Units Caused by Impropriety Heat Treatment

2013 ◽  
Vol 803 ◽  
pp. 393-396
Author(s):  
Hao Yang Du ◽  
Jian Yang ◽  
Chun Lei Zhang ◽  
Zhen An Ren
Keyword(s):  
Heat Treatment ◽  
Weld Metal ◽  
Storage Tank ◽  
Ostwald Ripening ◽  
Water Storage ◽  
Metallographic Examination ◽  
Water Storage Tank ◽  
Structure Of Water ◽  
Weld Joints ◽  
Cooling Speed

Hardness heterogeneous on weld metal and base metal in complicate structure of water storage tank was found after examination. Replica metallographic examination in hardness heterogeneous zone shows abnormal microstructures. Ostwald Ripening structure was caused by uneven temperature control during heat treatment. Lower cooling speed is the main cause of forming tempered sorbite in weld joints.

THE BENDABILITY AND FORMABILITY OF COLD ROLLED AND HEAT TREATED AZ31 MG ALLOY SHEETS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5919-5924
Author(s):  
INSOO KIM ◽  
SAIDMUROD AKRAMOV
Keyword(s):  
Heat Treatment ◽  
Tensile Stress ◽  
Rolling Direction ◽  
Ultimate Tensile Stress ◽  
Subsequent Heat Treatment ◽  
Mg Alloy ◽  
Bending Test ◽  
Tensile Tester ◽  
Heat Treated ◽  
Az31 Mg Alloy

In this study, strong {0002} textured (or strong ND//<0002> textured) AZ31 Mg alloy sheets were prepared. These AZ31 Mg alloy sheets were cut along the angles of 0, 12.5, 25, 30 and 37.5 degrees to the rolling direction or {0002} texture. Prepared samples with different angles to the rolling direction were rolled at room temperature and after subsequent heat treatment, the bendability, ultimate tensile stress, elongation and texture are investigated using the 3-points bending tester, tensile tester and x-ray diffractometer, respectively. The specimen having along the angles of 0 degree to the rolling direction shows the highest load and 45 degrees specimen shows the highest displacement among any other specimens in the bending test. The specimen having along the angles of 12.5 and 25 degrees to the rolling direction shows highest elongation and of 0 degree specimen shows the highest ultimate tensile stress among any other specimens after cold rolling and subsequent heat treatment at 150°C for 30 minutes in bending test.

Sign in / Sign up

Export Citation Format

Share Document