| 1 | General Category / Ask Peter, Metallurgical Engineer / Re: Mar quenchin and temper anneal the same part on: 08/19/10 at 11:21am |
| Started by edean | Post by phushek | |
| Beth, It sounds like you have a complex part on your hands. It is not uncommon in complex parts to have differing load factors which prevent a single heat treat treated condition from being applied to the whole part. It sounds to me like the whole part requires a harden and marquench operation typically utilized to reduce distortion. When the processing is complete for the first phase the entire part will have the 200/220 KSI strength. The part designer has determined that select areas need a lower strength level and therefore will require a specialized process involving the selective tempering of defined areas of the part. This process is called induction tempering. An induction coil is utilized to apply a localized heat to an area to temper it back to the 180/200 KSI range. The induction house will most likely require samples of the part or samples of similar shape and size to refine the heat input and time cycle to attain the desired properties. |
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| 2 | General Category / Ask Peter, Metallurgical Engineer / Mar quenchin and temper anneal the same part on: 08/18/10 at 7:17am |
| Started by edean | Post by edean | |
| I have a part that requires: Heat treat to 200 - 220KSI with mar-temper quenching in salt at 400°F. My question is that the end of the part also requires a distance of approximately one inch to heat treat 180 - 200ksi that distance only, with a .5" buffer zone to be heat treated to 180-220ksi. How can this process be completed and do you know who has the capability to do this? The part is 4340 and tube shaped with an OD of about 3.5" and ID of 1.3" and about 12" long. Thank you, Beth |
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| 3 | General Category / Ask Peter, Metallurgical Engineer / Elongation during Ion Plasma Heat Treat on: 08/16/10 at 9:22am |
| Started by ccboushek | Post by ccboushek | |
| I am an engineer at a company that makes long slender gear racks, rough and tough .75" x 1.75" x 40". These racks go through an Ion Plasma Nitriding process. This process was chosen because of the large consensus that it is a very stable process (i.e. very little distortion occurs during the process). From our experience every piece of rack that has gone through this heat treatment has grown (not volumetric growth that is mentioned often times when talking Ion Plasma but an elongation of up to .010" over 40"). 10 thou doesn't seem like much but our tolerance is +/-.002". My question is: 1) Has anyone delt with Ion Plasma Nitriding as a final op (no post machining) and been able to hold tolerances this closely? 2) Can anyone describe WHY the growth occurs or what factors effect the amount of growth? I look forward to all of your thoughts. Thanks |
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| 4 | General Category / Ask Peter, Metallurgical Engineer / Re: Beryllium Copper on: 06/16/10 at 9:57am |
| Started by chipman | Post by phushek | |
| The heat treater usually sends it out. The testing spec is ASTM E-8 and it will require a 3" long sample of bar stock. We recommend that customer send two test samples with each order in case there is an issue in the actual testing procedure. Usually there is not but it is an inexpensive insurance measure. | |
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| 5 | General Category / Ask Peter, Metallurgical Engineer / Re: Beryllium Copper on: 06/10/10 at 11:38am |
| Started by chipman | Post by chipman | |
| Peter, My B/P calls out Heat Treat to condition HT per PS15935 TO 175,000 PSI MIN. Can Phoenix H.T. do the tensile testing also? If not where can I get that done? Thanks, Steve |
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| 6 | General Category / Ask Peter, Metallurgical Engineer / Re: Beryllium Copper on: 06/10/10 at 11:25am |
| Started by chipman | Post by phushek | |
| Like easy questions occassionally. The material can be processed before or after machining. These alloys come typically in the solution treat or solution treated and cold worked condition so we are only precipitation hardening them. According to the spec the hardness must be 38 HRC minimum after processing. We usually see the hardness be a few point above the minimum on the bar stock so it would be in the 38/42 HRC normally. The material shrinks slightly during the processing so often we see machined parts come in near finish machined. Since you callout is for 175 KSI and the spec does not mention mandatory tensile testing it would make sense to have an additional 3" length sent in with the order to make sure your are able to obtain a report on the KSI should your customer actually require it. As I read it the spec is only mandating HRC testing. | |
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| 7 | General Category / Ask Peter, Metallurgical Engineer / Beryllium Copper on: 06/10/10 at 6:53am |
| Started by chipman | Post by chipman | |
| Peter, I have a job that calls out Beryllium copper per QQ-C-530 and Heat Treat to condition HT per PS15935 TO 175,000 PSI MIN. The bar is only 1" x 1.5" x 24" long. Can we heat treat before we begin machining and what will the hardness be? Thanks, Steve Schwartzkopf Chips, Inc. |
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| 8 | General Category / Ask Peter, Metallurgical Engineer / Re: Fixturing for heat treat on: 03/05/10 at 11:01am |
| Started by eddy | Post by phushek | |
| Thank you for the question. I know that many people have questions and concerns along these lines. The foundation of the question lies in the material under discussion and the final condition required for the part. There is a dirty little secret that most people suspect but have never been told straight out. Nearly all material in bar, sheet or plate comes to you with internal stresses free or charge. You see if they attempted to send it stress free it would never meet the tolerances for straightness, flatness or general uniformity of dimensions. Understandably, most people would not buy crooked bar, wrinkled sheet or wavy plate so they "cold finish" the product before sending it from the mill to the distributors. So here we all are with prestressed product trying to make tight tolerance parts. I have worked with many customers in the past to reduce the stresses at the most logical point in the manufacturing process so that they can be contained or significantly reduced. If the part is simply welded and sold in such a condition stress relieving before the weld is much more advantageous than after the distortion has manifested itself. Each part, each design, each material and sometimes each material lot from different mills has to be considered on its own merit. In general, reduce the stresses before they make you want to cry and looking at it from a point of knowledge and consideration is a well worn path of success. Remember, the mud in the Mississippi came from upstream and the same is true of the stresses in your metal. Fixturing needs to address secondary operations and whether processing is required which may require some critical heat transfer issues which must be considered before fixturing designs can be approved. I hope this was informative. | |
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| 9 | General Category / Ask Peter, Metallurgical Engineer / Fixturing for heat treat on: 02/26/10 at 10:02am |
| Started by eddy | Post by eddy | |
| Pete - I want to say that I love this idea about this forum! I have been in contact with you about many projects that require heat treating and we have discussed fixtureing solutions. When we do have these special projects and questions regarding fixturing or manufacturing, what would be the best way to discuss our initial plan of attack? I know our welder has questions regarding excess stress we add to parts particularly with the flatness tolerances and true position of holes after weld. What is the best way to communicate these specific concerns? Again, I value your input. You guys have always led me down the right path in achieving success in our projects. THANK YOU ! eddy - |
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| 10 | General Category / Ask Peter, Metallurgical Engineer / Re: Flame hardening 8630 - mod on: 02/24/10 at 4:00pm |
| Started by Keath Beifus | Post by phushek | |
| Keath, Good question. I have reviewed the normal chemistry for 8630 and the normal hardenability for the alloy which tells me you should be OK with the material you currently have for the order. The way you can tell for yourself is to look at the material certification and find, hopefully it is on the cert, the Jominy Hardenability Data. This information tells you how the material responds to a harden and water quench test. It is typically reported in increments of 0.125". The normal 8630 shows a range of hardness from 35 to 48 HRC which takes into account many chemistries from a wide range of heat lots. The extra chrome and moly that you have in you "modified" chemistry should take you into the mid 40s to low 50s HRC. As long as you choose an induction or flame hardener who knows his setting and cycle times I think you will be fine with the material you have now. If you would like me to review the cert myself please contact me directly through the main phone line. |
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