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It is will known that most of tool steels are quenched in oil to prevent cracking and distortion which appears when quenching in water due to non-uniform cooling caused by formation of insulating vapor blanket "film boiling".

but according to some literature 1 using 14% brine solution or 1% polymr solution eliminate this vapor blanket so we can expecting more uniform cooling compared to water quenching.

according to another literature 2 the probability of quench crack formation at first increases to the maximum value, and then decreases to zero. enter image description here

increasing cooling rate is possible by using strongly circulated brine quenching bath, and using brine eliminate vapor blanket which ensure uniform cooling.

so, can we excepting maximum hardening depth, minimal cracking and distortion and eliminated fire hazard by quenching high alloy tool steels by quenching in circulated brine instead of oil ?

Rhodie
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madara
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2 Answers2

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The quench all depends on the grade of steel that you are working with. Each steel is specially formulated to be used for a specific type of application. As others have stated you need to narrow down your material then investigate from that point. I don't know how anyone could answer this vague of a question with any accuracy.

The following list gives a brief description what each Grade of tool steel is:

  • A Series: Air Hardening, Cold Work Tool Steel, Air Quench Only
  • D Series: High Carbon, High Chromium, Cold Work Tool Steels, All D grade except D3 are quenched in either air or salt bath
  • L Series:Low Alloy Special Purpose Tool Steels, Use many different methods to quench including molten salt baths for some
  • P Series: Mold Steels, most use oil or brine to quench.
  • H Series: Hot Work Tool Steels, Molton Salt Bath, Atmosphere or Vacuum to quench.
  • T Series: Tungsten High-Speed Tool Steels, these are quenched in air, oil or molten salt.
  • M Series: Molybdenum High-Speed Tool Steels, these are quenched in air, oil or molten salt.

Most of these materials are tested by time and usage for decades and most heat treat companies have perfected the processes they use to ensure a good finished product.

Every type of steel will react different to one specific heat treatment. This why there are so many methods. Each method is used for a specific purpose. So to answer your question broadly, no brine cannot be used for all types of tool steel and still have a good product. Some will crack some will distort. each type of steel needs to be quenched so the steel can accurately cool down at a specific rate to get the desired end result for each type of steel.A brine bath will not do this for all tool steels.

sgwilliams
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I would say it really depends on the tool steel being used. I read that its recommended for water hardening steels to be quenched in a brine solution opposed to straight water, so perhaps there's some validity to the statement. Whether or not you can quench an oil hardening steel in water/brine, id imagine water quenching an O type steel would "shock" the part too much, promoting cracking of thin sections and brittleness. I also wouldn't try and quench an air hardening material in a liquid for the same reasons.

Corey
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