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  • 1.  1030 steel induction heat treat issues

    Posted 21 days ago

    I am reaching out for some insight into our current situation. We have to switch steel suppliers due to some unforeseen circumstances. In lieu of this our current supplier provides us with a 1030M that we induction heat treat and rapid quench. We have been looking into other suppliers to provide us the same or close comparison to it. Upon receiving the sample steel, we are unable to dial in the steel as to even close to our current recipe/process. Up to this point we have tried to dwell the parts going from the actual heat treat to the UConn A quench bath. We also have tried multiple settings of adjusting our power, current, and heat treat time at the heat treat unit itself. Currently all our trial runs have proven ineffective to gain the Rockwell C results from our current steel supplier. I am not familiar enough with the actual steel mill processing and what could make this such a drastic change for us. this is new territory for us as we have used the same supplier for over 20 years. But as times have changed, we need to make product from a completely new supplier.

    Any help is greatly appreciated in this.



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    Rodney Recore
    Plant Process Metallurgist
    Gasport NY
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  • 2.  RE: 1030 steel induction heat treat issues

    Posted 20 days ago

    Chemistry, grain size, and structure matter. 

    The hardenability (D.I.) value of that grade could vary greatly due to small alloy additions or not. Check your two chem certs in a hardenability calculator (SAE J406 / ASTM A255). Also, the minor chems could affect how quickly you have to quench and miss the knee of the TTT. 

    Grain size coming to you could affect post-heat treat grain size and hardness.

    Also, the mill structure coming to you matters. If it's cold rolled, it could recrystallize/nucleate grains on the way up to austenite during induction heating. If it's a very annealed, open pearlite and ferrite structure, or even spheroidized structure, it will take longer at temp or higher temp to fully austenitize before quench.



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    Greg Ward, P.E.
    Metallurgist
    Auburn, MI
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    IMAT Conference & Expo


  • 3.  RE: 1030 steel induction heat treat issues

    Posted 20 days ago
    Hi Rodney,

    When you change raw material subject to induction hardening, you will have to re-optimize the process. The electrical properties such as relative magnetic permeability and resistivity of steel change with prior processing. The thermal conductivity also plays a role in that it helps dissipate heat from the surface quickly. I would recommend you carry out your trials while measuring the surface temperature of the part to ensure that you fully convert the surface to austenite. The temperature would have to be at least 50 deg C above the ferrite/austenite phase boundary. The residence time can be optimized to fully convert the surface to austenite. 

    You can check your process by quenching the part and measuring the as-quenched hardness. The as-quenched hardness is determined only by the carbon level and not by prior processing. If the as-quenched hardness is lower than the listed value for the 0.3% carbon steel, you may not be fully austenitizing the surface, or you are taking too long to quench, or steel surface carbon is too low.

    Good Luck!

    Ratnesh Dwivedi, Ph.D.
    President
    RKD ENGG, LLC



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  • 4.  RE: 1030 steel induction heat treat issues

    Posted 20 days ago
    Great advice from Greg Ward and right on point. You may also consider sweetening up the material to improve hardenability with a higher level of carbon and/or alloy addition to make it more responsive to the induction hardening. Another option would be speeding up the quench severity of the quenchant (not sure what your polymer concentration is) however you need to be cautious here as this could lead to cracking issues especially if tempering is delayed.

    Bob Ferry




    IMAT Conference & Expo