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Study on Effect of Laser Peening on Inconel 718 produced by DMLS technique

Vellore Institute of Technology-Nattudurai Navin Kumar, Aditya Chandrakant Yadav, Kumar Raja, Subramanian Prabhakaran, Chooriyaparambil Damodaran Naiju, Sivaperuman Kalainathan
  • Technical Paper
  • 2019-28-0146
To be published on 2019-10-11 by SAE International in United States
In Additive manufacturing, Direct Metal Laser Sintering is a rapid manufacturing technique used for manufacturing of functional components. Finely pulverized metal is melted using a high-energy fibre laser, by Island principle strategy produces mechanically and thermally stable metallic components with reduced thermal gradients, stresses & at high precision. Inconel is an austenitic chromium nickel based super alloy often used in the applications which require high strength & temperature resistant. It can retain its properties at high temperature, e.g. Engine components in aerospace, exhaust system in automobile applications etc. Here we attempts to analyze the effect of laser shock peening on DMLS Inconel 718 sample. Microstructure shows elliptical shaped structure and formation of new grain boundaries. Surface roughness of the material has been increased due to effect of laser shock pulse & ablative nature. 13 % Increase in macro hardness on the surface. Depth wise micro hardness was investigated, found to be 17% increase on the sub layer of the material due to the effect of hardened matrix formed by precipitation hardening and grain size refinement…

Assessment of tribo meter study of 20MnCr5 alloy steel under case hardened and shot peened condition

Shanthi Gears Limited-Vignesh Nataraj
Sri Krishna College of Engg. and Tech.-Soundararajan Ranganathan, Janarthanan Prakash, Dinu Mathew
  • Technical Paper
  • 2019-28-0098
To be published on 2019-10-11 by SAE International in United States
This research is constrained to study the strength and wear resistance of 20MnCr5 (SAE 5120) alloy steel under monolithic, case hardened and case hardened with shot peening processing condition. Improve the hardness of the material by enhancing the core and surface strength of case hardened with shot peened sample. The principle goal of this proposed work is to conduct the tribo meter test for the three test samples by differing the load of 5, 10, 15 and 20N and sliding speed of 290,580,870 rpm respectively. The impact on tribo meter process parameters on wear rate and co-efficient of friction be calculated and recorded for this study. Less wear rate and nominal co-efficient of friction was observed for case hardened with shot peened sample. Load and sliding distance increases wear rate decreases and co-efficient of friction increases for all the tested samples due to oxide layer formation. After reaching certain load and sliding speed the curve goes linear because of more contact between pin and disc, so that mechanical amalgamation layer will be framed. On the…

Influence of Retained austenite on fatigue performance of carburized gears

Comstar Automotive Tech P Ltd.-Rajeshkumar Ramasamy, Seenuvas Sivathanu, Varatharaj Neelakandan, Thulasirajan Ganesan, Praveen Chakrapani Rao
  • Technical Paper
  • 2019-28-0102
To be published on 2019-10-11 by SAE International in United States
SAE 8620 and 20MnCr5 are widely used materials for gears in automotive application. The materials were subjected to carburizing process to obtain the identical hardened layer of HRC 61-64. The carburized surface and core properties of the materials were examined and characterized through optical microstructure to measure the presence of cementite carbides and Retained Austenite (RA). From the results, it was found that the SAE 8620 and 20MnCr5 materials have 10 % and 14% of RA respectively. Whereas, the core and case structure were free from network carbides. The fatigue test were conducted to correlate the RA and fatigue strength of the materials. It was revealed that material with lower RA has higher fatigue strength than material with higher RA. Higher the amount of retained austenite leads to reduction in amount of martensitic and compressive residual stress attributed to lower the contact fatigue strength. Untransformed austenite is metastable and it is transformed to untempered martensite, which causes brittleness to the component and leads to premature failure.

Effect of Cryogenic Treatment on Inconel 718 Produced by DMLS Technique

Vellore Institute of Technology-Chooriyaparambil Damodaran Naiju, Kumar Raja, Nattudurai Navin Kumar, Chandrakant Yadav Aditya, Muniappan Senthil Kumar
  • Technical Paper
  • 2019-28-0140
To be published on 2019-10-11 by SAE International in United States
The main purpose of this study is to investigate additive manufactured Inconel super alloy subjected to Cryogenic Treatment (CT). Cryogenic treatment mainly used in aerospace, defence and automobile application. Direct Metal Laser Sintering is an Additive manufacturing technique used for manufacturing of Complex and complicated functional components. Inconel is an austenitic chromium nickel based super alloy often used in the applications which require high strength & temperature resistant. In this work, we have made an attempt to study microstructure and mechanical properties of additive manufactured Inconel 718 when subjected to cryogenic treatment at three different time intervals. The micro-structural evolution of IN718 super-alloy before and after CT was investigated by both Optic Microscope (OM) and SEM. Surface roughness and hardness at different CT time intervals has also analyzed. Additionally, XRD technique was used to analyze the surface residual stress. The result shows after three cycles of CT-1(CT-2, CT-3), the hardness of Inconel 718 has been substantially improved at room temperature. Microstructure shows grains in CT-3 condition larger number of refined and uniformly distributed strengthening precipitates…

Heat Treatment of Carbon and Low-Alloy Steel Parts Minimum Tensile Strength Below 220 ksi (1517 MPa)

AMS E Carbon and Low Alloy Steels Committee
  • Aerospace Material Specification
  • AMS2759/1G
  • Current
Published 2019-06-17 by SAE International in United States
This specification, in conjunction with the general requirements for steel heat treatment covered in AMS2759, establishes the requirements for heat treatment of carbon and low-alloy steel parts to minimum ultimate tensile strengths below 220 ksi (1517 MPa). Parts are defined in AMS2759. Due to limited hardenability in these materials, there are size limits in this specification.
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ACBG Rolling Element Bearing Committee
  • Aerospace Standard
  • AS21439D
  • Current
Published 2019-06-06 by SAE International in United States
No Abstract Available.
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Test Strip, Holder, and Gage for Shot Peening

Surface Enhancement Committee
  • Ground Vehicle Standard
  • J442_201906
  • Current
Published 2019-06-06 by SAE International in United States
This SAE standard defines requirements for equipment and supplies to be used in measuring shot peening arc height and other surface enhancement processes. Guidelines for use of these items can be found in SAE J443 and SAE J2597.
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Joining Gun Bonds Metal and Plastic in Seconds

  • Magazine Article
  • TBMG-34612
Published 2019-06-01 by Tech Briefs Media Group in United States

The connection of plastics and metals poses a challenge due to the different physical properties of the two materials. All conventional joining options, such as bonds using adhesives or rivets, have their disadvantages — adhesives need time to harden, which delays further processing, and plastics can be easily damaged during riveting. Furthermore, both adhesive bonding and riveting require additional materials that increase production costs.


Heat Treatment of Steel Raw Materials

AMS E Carbon and Low Alloy Steels Committee
  • Aerospace Material Specification
  • AMSH6875B
  • Current
Published 2019-05-29 by SAE International in United States
This specification covers the requirements for heat-treatment of four classes of steel (See 1.2) and the requirements for furnace equipment, test procedures and information for heat-treating procedures, heat-treating temperatures and material (See 6.3) test procedures. This specification is applicable only to the heat treatment of raw material (See 6.3.1); it does not cover the requirements for the heat treatment of steel parts (See 3.4 and 6.3.2). This specification also describes procedures that, when followed, will produce the desired properties and material qualities within the limitations of the respective alloys tabulated in Tables 1A, 1B, 1C and 1D. Alloys other than those specifically covered herein may be heat treated using all applicable requirements of this specification.
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Open Access

Monotonic and Cyclic Creep of Cast Materials for Exhaust Manifolds

SAE International Journal of Materials and Manufacturing

Royal Institute of Technology, Sweden-Christian Öberg, Stefan Jonsson
Scania, Sweden-Baohua Zhu
  • Journal Article
  • 05-12-02-0012
Published 2019-05-13 by SAE International in United States
Cast materials are creep tested between 600 and 900°C using three methods: (i) tensile testing at different strain rates, (ii) stress relaxation during thermal cycling and (iii) traditional creep tests at constant load. Comparisons are made between fast and slow methods and between monotonic and cyclic deformation modes. The tested materials, SiMo51, SiMo1000, Ni-resist D5S and HK30, are used for exhaust manifolds in heavy-duty diesel engines. The fast and cheap methods, (i) and (ii), were used on all materials, while the tedious and costly method, (iii), was used on SiMo51 only. The creep rates from monotonic tensile tests and stress relaxations during thermal cycling agree well. There is no difference between monotonic and cyclic creep rates, and cyclic rates are practically unchanged with the number of thermal cycles. No or small differences in creep rates are observed when comparing tension and compression, although three of the materials include large graphite nodules. At 700°C, a Norton plot for SiMo51 shows coinciding results for tensile test and compressive stress relaxations, whereas the minimum creep rates from constant…