Friction surfacing involves complex thermo-mechanical phenomena. In this study, the nature of dynamic recrystallization in friction surfaced austenitic stainless steel AISI 316L coatings was investigated using electron backscattered diffraction and transmission electron microscopy. The results show that the alloy 316L undergoes discontinuous dynamic recrystallization under conditions of moderate Zener-Hollomon parameter during friction surfacing. © 2012 Elsevier Inc. All rights reserved.

Janaki Ram G D

Department of Metallurgical and Materials Engineering

AUSTENITIC STAINLESS STEEL COATINGS

DISCONTINUOUS DYNAMIC RECRYSTALLIZATION

EBSD

Electron back-scattered diffraction

FRICTION SURFACING

Thermo-mechanical

ZENER-HOLLOMON PARAMETER

Austenitic stainless steel

Coatings

Electron microscopy

Friction

Friction welding

Transmission electron microscopy

Dynamic recrystallization

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials Characterization

Multi-layer friction deposits in nickel-based superalloy Inconel 718 were investigated for their heat-affected zone liquation cracking resistance. The friction deposits, owing to their fine-grained microstructure with a large number of subgrain boundaries and fine, uniformly distributed carbide particles, were found to exhibit superior liquation cracking resistance to standard wrought-processed alloy 718. Based on these findings, a new technique involving friction deposition of the base plates prior to fusion welding was proposed for overcoming liquation cracking. © 2017, The Minerals, Metals & Materials Society and ASM International.

Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science

Use of Friction Buttering for Overcoming HAZ Liquation Cracking

This work offers a fresh perspective on buttering, a technique often considered for fusion welding of dissimilar metals. For the first time, buttering was attempted in solid state using friction deposition. Using this new “friction buttering” technique, fusion welding of two different dissimilar metal pairs (austenitic stainless steel/borated stainless steel and Al-Cu-Mg/Al-Zn-Mg-Cu) was successfully demonstrated. The results show that friction buttering can simplify a tough dissimilar welding problem into a routine fusion welding task. © 2017, The Minerals, Metals & Materials Society and ASM International.

Friction Buttering: A New Technique for Dissimilar Welding

Friction Freeform Fabrication is a new solid-state additive manufacturing process. The present investigation reports a detailed study on the prospects of this process for additive part fabrication in superalloy Inconel 718. Using a rotary friction welding machine and employing alloy 718 consumable rods in solution treated condition, cylindrical-shaped multi-layer friction deposits (10 mm diameter) were successfully produced. In the as-deposited condition, the deposits showed very fine grain size with no grain boundary δ phase. The deposits responded well to direct aging and showed satisfactory room-temperature tensile properties. However, their stress rupture performance was unsatisfactory because of their layered microstructure with very fine grain size and no grain boundary δ phase. The problem was overcome by heat treating the deposits first at 1353 K (1080 C) (for increasing the grain size) and then at 1223 K (950 C) (for precipitating the δ phase). Overall, the current study shows that Friction Freeform Fabrication is a very useful process for additive part fabrication in alloy 718. © 2013 The Minerals, Metals & Materials Society and ASM International.

Friction freeform fabrication of superalloy inconel 718: Prospects and problems

A new additive manufacturing process, termed "friction freeform fabrication," has been recently proposed by the authors. One of the unique capabilities of the process is that it can facilitate fabrication of three-dimensional parts in materials that are difficult to fusion deposit. The current study is a striking demonstration of this, in which cylindrical samples of 40 mm height and 10 mm diameter were successfully produced in borated stainless steel ASTM 304B4, a material known to be very difficult to fusion weld or deposit. Microstructures and mechanical properties of these samples were investigated in detail and were compared to those of standard wrought-processed alloy 304B4 Grade B material. © 2013 ASM International.

Journal of Materials Engineering and Performance

Microstructures and properties of friction freeform fabricated borated stainless steel

How microstructures evolve in heat-treatable aluminum alloys during multi-layer friction deposition is an intriguing question. The current work shows that the process invariably leads to overaging of strengthening precipitates in such materials as alloy 2014. The problem can be overcome using a solution treatment, but it can lead to other problems such as abnormal grain growth. Based on these findings, it appears that the benefits of friction deposition cannot be fully realized in heat-treatable aluminum alloys. © 2013 Elsevier Inc.

Microstructure evolution in aluminum alloy AA 2014 during multi-layer friction deposition

Coatings of AISI H13 tool steel were made on low carbon steel by friction surfacing. Detailed microstructural studies and microhardness tests were carried out on the coatings. Studies revealed defect-free coatings and sound metallurgical bonding between the coating and the substrate. In addition, mechanical interlocking on a very fine scale was observed to occur between the coating and the substrate. Coatings exhibited martensitic microstructure with fine grain size and with no carbide particles. Coatings in as-deposited condition showed very high hardness (58 HRC) compared to the mechtrode material in annealed condition (20 HRC). Based on these findings, microstructural evolution during friction surfacing of H13 tool steel is discussed. The current work shows that friction surfaced tool steel coatings are suitable for use in as-deposited condition. Further improvements in coating microstructure and properties are possible with appropriate post-surfacing heat treatment. © 2010 Elsevier Ltd.

Materials and Design

Microstructural evolution during friction surfacing of tool steel H13

Friction surfacing is a candidate process for depositing corrosion and wear resistant coatings. Being a solid-state process, it offers several advantages over conventional fusion welding based surfacing process. In the current work, martensitic stainless steel AISI 410 was friction surfaced over mild steel substrates. Coating microstructures were characterized using light microscopy, scanning electron microscopy and Xray diffraction. Coatings in as-deposited condition exhibited a fully martensitic microstructure and were found to be quite hard (with an average hardness of 460 HV). Bend and shear tests indicated excellent coating/substrate bonding. Overall, the current work shows that martensitic stainless steel AISI 410 can be satisfactorily friction surfaced on mild steel. © 2011 Indian Institute of Metals.

Transactions of the Indian Institute of Metals

Characterization of friction surfaced martensitic stainless steel (AISI 410) coatings

Tool steel H13 was friction surfaced on low carbon steel substrates. Mechtrode (consumable rod) rotational speed and substrate traverse speed were varied, keeping the axial force constant. The effects of process parameters on coating characteristics and integrity were evaluated. A process parameter window was developed for satisfactory deposition of tool steel coatings. Coating microstructures were examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microhardness tests, shear tests, and bend tests were conducted on coatings. The results show that coating width is a strong function of mechtrode rotational speed, while coating thickness is mainly dependent on substrate traverse speed. Lower mechtrode rotational speeds results in wider coatings, while higher substrate traverse speeds produce thinner coatings. Thinner coatings exhibit higher bond strength than thicker coatings. Coatings show no carbide particles, yet exhibit excellent hardness (above 600 HV) in as-deposited condition due to their martensitic microstructure. © 2010 Elsevier B.V.

Surface and Coatings Technology

Friction surfaced tool steel (H13) coatings on low carbon steel: A study on the effects of process parameters on coating characteristics and integrity

Friction surfacing is a novel solid state surface coating process with several advantages over conventional fusion welding based surfacing processes. In this work, austenitic stainless steel (AISI 310) and tool steel (H13) coatings were friction deposited on mild steel substrates for corrosion and wear protection, respectively. Microstructural studies were carried out by using optical and scanning electron microscopy. Shear tests and bend tests (ASTM A264) were conducted to assess the integrity of the coatings. This study brings out the microstructural features across the coating/substrate interface and its mechanical properties, showing good metallurgical bonding between stainless steel and tool steel coating over mild steel. © (2010) Trans Tech Publications.

Journal	Materials Characterization
ISSN	10445803
Open Access	No