Retained Austenite [RA] & Un-Tempered Martensite [UTM] the primary obstacles for the poor performance of indigenous Toolings [Metallurgical-perspective, for course correction]

[madhav kapdi]

                Sub. : Retained Austenite [RA] & Un-Tempered Martensite [UTM] the primary obstacles for the poor performance of indigenous Toolings [Metallurgical-perspective, for course correction]

 

                Barring few, none of the PDC units I have interacted with are getting a Tooling life past 1.00 lakh shots, while I understand, abroad the norm is well past 2,00 / 2.50 lakhs. Indian Die-makers & Die-casters, have not been able to identify where the shoe is pinching, but blame the HT vendors [Metallurgists] as a ritual. Some have installed in-house Vacuum Heat-treatment [VHT] furnaces [Overseas practice] but still there is no improvement.

 

                In my opinion, it is not the hardware [HT furnaces] but the software [Die-Design] that is at fault. As a Metallurgist, following two parameters are primarily responsible for the poor performance of our Toolings,

 

                01] Retained Austenite [RA] : Excessive amount of RA [Due to poor Die-Design] is responsible for the mould dilation, and the subsequent crack formations. Dilation takes place during the conversion of Austenite, a FCC structure, into Martensite, a BCT structure. The former has a higher Density than the latter and the differing Densities, generates the stresses, leading to the crack formation.

 

                02] Un-Tempered Martensite [UTM] :  UTM is unstable, being an intermediate product. While stabilizing [converting to the stable Martensite] it releases the energy, which generates the stresses, resulting in the crack formations.

 

                Late Mr.M.A.K.Babi, a Metallurgist from M.S.University Baroda 1971 batch, has put forth his versions on both the parameters in a Tech-talk column of the Search magazine, based on the specific queries framed by the writer, at his request. Guided by his suggestions [Eddy current testing] we can spot the presence of RA & UTM in our Toolings.

 

                We should also check the above parameters of imported Toolings [which gives the international standard performance] to generate a benchmark. My version is  " Absence of the Metallurgical software [Know-why] is a primary reason for the poor performance of our Toolings." So instead of shooting in the dark at random, we should have  a systematic approach for the Metallurgical investigations.

 

                I would like to put forth my suggestion as under,

 

                01] Collect the readymade project reports from the Educational institutions.

                02] Identify the operating problems in your shop, and assign a project for the under-Graduate and absorb him for the implementation.

                03] Appoint a consultant.

 

                In any of the above combinations, as a Tooling manufacturer & consumer, you should have some amount of in-house Metallurgical knowledge, for the interaction with the consultant. Mr.Babi has addressed both the parameters and his response for the Un-Tempered Martensite [UTM] appearing in the Oct. 2007 issue of Search magazine is enclosed.

 

                He has also addressed a query about the RA but I was not able to locate the same. However, I have generated my own response in my article " In-Situ Metallography for the Metallurgical investigations." With due respect, the writer can not be a substitute for the Babi Saheb, hence the readers should hunt for his original response to enrich themselves.

 

                This appears to be a time consuming process. Can it be shortened.?

 

                This statement is a sign of your reservations to Metallurgy called as allergy. You have been able to extract only 10% of HDS Tooling performance potential, on account of your allergy, which you need to introspect, for your own benefit.

 

                There is no short-cut for success, but the process can be shortened to an extent. You can be presented with a Technology Demonstration, in the Plunging-system package supplies as under,

 

                01] SS & SB, both are made of Hot Die-steel [HDS] like PDC Dies. We can implement various options presented in my  article  ` Unexplored  potential of Tool-steel Metallurgy, for PDC applications." in SS & SB to begin with. Once these options are ratified with its authentic operational feedback, then those options can progressively be introduced in PDC Dies, the high value assets of PDC industries.

 

                02] Fortunately, the Cross-sections of both the items [SS & SB] are fairly uniform across the length, hence there is no scope for excessive amounts of RA [Due to inherent HT friendly Design] unless you mess up with the HT. However, such luxury is not available for PDC Dies, hence the Die-Designer will have to sweat out on this aspect diligently, to reduce the quantum of RA, to the bare minimum.

 

                RA & UTM are Design-specific and Interdependent. If you are able to control the RA, then UTM is automatically taken care of as a ripple effect. But before then, the Die-Designers should convince themselves that the reduction of RA is possible only with the HT friendly Die-Design. So plz do not blame your HT Vendors & Metallurgists, unless you abide by your own obligations, to begin with.

 

                Bottom lines.

 

                01] The prevailing poor Tooling performance is a boon for the HDS & HT vendors. Any improvement will harm their business, hence they will resist even if they are enticed. Obviously then, the Die manufacturers are left with no alternative, than to improve their own Die-Design, than blame the vendors.

 

                02] Such blaming has not helped you so far, nor will it help in future either. On the contrary, with such unsavoury behaviour, the competent vendors will stay away from you, which you might have very well experienced by now.

 

                03] While the Mechanical engineers are allergic to Metallurgy in General, but even we Metallurgists are also allergic to Tool-steel Metallurgy in particular, in view of its miniscule requirement. Primarily, I am a Foundryman with experience in Cast-Iron Metallurgy, hence took the Plunger for Development, but I have to detour in Tool-steel Metallurgy [HDS] since, the Plunging-system package calls for it.

 

                Point to ponder.

 

                01] Tool-steel Metallurgy, is at the core of our massive Defence imports, hence we have to master it, to become Atma Nirbhar. It is a virgin branch of Metallurgy in India, with a tremendous Value addition & Growth potential, with the first mover advantages.

 

                Kindly De-dust your college books, to re-acquaint with the terminology used. If the above deliberations are still difficult to grasp with, then you will have to arrange for my lecture on the subject, to explain the same in person.

 

 

                Madhav Kapdi.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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