Valery Rudnev

Dr. Valery Rudnev, FASM also known among professionals as "Professor Induction" welcomes you to his monthly blog! Since 1993, Dr. Rudnev has been on staff at Inductoheat Inc., where he services customers with scientific and technological expertise. His credentials include more than 30 years of experience in induction heating, more than 40 patents and 200 scientific publications. He also co-authored the "Handbook of Induction Heating" and eight (8) chapters for several handbooks devoted to various aspects of induction heating, heat treating, computer modeling and process development.

This blog will serve as Q&A for materials science, metallurgy, electromagnetics, induction heat treatin. Dr. Rudnev provides his expertise pro bono and will reply to your questions as soon as possible.

______________________________________________________________________________________________ Question of the Month: For a few years, we scan hardened relatively straight shafts using a 30 kHz machine. Our new component has a 4.8-mm radial step (sharp shoulder) that melted when we tried to scan harden. We heard that a single-shot inductor could reduce shoulder overheating and still provide sufficient hardening, so we […]

September 30th, 2016 : Posted in Induction Billet Heating, Induction Forge Heating, Induction Heating, Metallurgical Aspects : Comments Off   

______________________________________________________________________________________________ Question of the Month: We process copper alloy bars and billets in our factory. Gas furnaces have been used to heat billets made of C14500, C44300, C46400, C48500, C64200, and others. Billet/bar diameters are within the 200-240 mm range. The maximum temperature of our furnace is 860oC, which is sufficient for these jobs. However, […]

______________________________________________________________________________________________ Question of the Month: For quite a while after scan hardening, we experience low hardness readings (52-55 HRC) in areas where the diameter of our 1045 steel hollow shaft changes. We have consulted with induction heating specialists, but have not eliminated the problem. What causes soft spots at these locations and how we can […]

______________________________________________________________________________________________ As some of you may recall, the first Professor Induction column appeared in the June/July 2003 issue of Heat Treating Progress magazine. From the beginning, this column was intended to answer various questions from readers. Since that time, nearly 100 installments have appeared in Heat Treating Progress (2003-2009) and HTPro eNews (2011-present). The mission […]

March 25th, 2016 : Posted in Induction Heating : Comments Off   

______________________________________________________________________________________________ Numerous factors related to premature inductor failures were reviewed in the previous 20 issues of this Professor Induction column. Various measures have been discussed to help to increase the longevity of hardening inductors as well as induction coils used in other induction thermal applications. In some cases, a particular inductor style may be prone […]

______________________________________________________________________________________________ Preventive maintenance (PM) is a relatively simple but effective way to extend the life of induction coils because it maximizes uptime and minimizes the number of scrap parts. However, regardless of its obvious effectiveness, PM is often neglected. This leads to premature failure of machine components including problems associated with coils, fixtures, tooling, cooling/quenching […]

______________________________________________________________________________________________ When an alternating current flows through an electrical conductor, the current distribution is not uniform. One of the most important electromagnetic phenomena that dramatically affects the current distribution within any current-carrying conductor, including the inductor copper, is the electromagnetic proximity effect. Inaccurate judgment of the appearance of this phenomenon frequently results in localized overheating, […]

______________________________________________________________________________________________ Over the years, induction practitioners have established a family of special or specialty inductors. Common names have been coined to describe their appearance or function, such as pancake, channel, hairpin, split-return, and butterfly inductors. Split-return inductors are used in various applications including hardening, annealing, tempering, stress relieving, bonding, brazing, and soldering. For example, Fig. […]

______________________________________________________________________________________________ The May-July installments of the Professor Induction column discussed application specifics and some root causes of premature failures of inductors for heating internal surfaces, along with some tips to prevent such failures. This installment continues reviewing various failure modes associated with this type of inductor. Failure mode #4. Some inductor builders fabricate coils that […]

______________________________________________________________________________________________ The May and June installments of the Professor Induction column discussed application specifics and some root causes of premature failures of inductors for heating internal surfaces, along with some tips to prevent such failures. This installment continues reviewing various failure modes associated with this type of inductor. Failure mode #3. Installation of a magnetic […]

The postings on this blog are of Dr. Valery Rudnev and contain his personal thoughts, views and opinions and do not represent those of Inductoheat Inc. or Radyne Corporation.