Is there any standard or thumb rule to decide the holding/ soaking period of temperature during normalizing heat treatment of carbon steel castings with thickness varying from 4 inch to 8 inch? I believe 1/2 hour per inch of thickness is sufficient for normalizing at 1650F/ 900C.
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Holding period of normalizing temperature of steel castings 1
- Thread starter tamal1475
- Start date
Typically, from 4 to 8 inches the rule of thumb is 1 hour per inch of thickness up to 5" material thickness. Beyond 5" is 15 minutes for each additional inch of thickness, so...
5 hours + 45 minutes ~ 6 hours. This all depends on the furnace size and survey of the furnace to ensure uniform heating.
5 hours + 45 minutes ~ 6 hours. This all depends on the furnace size and survey of the furnace to ensure uniform heating.
Agree with metengr's comment. If your furnace is not uniformly heated, I would add another hour. You may see the castings portion near the door, being dark.
The problem of having uniform temperature in the furnace is important during tempering, where the mode of heat transfer is by convection.
"Even,if you are a minority of one, truth is the truth."
Mahatma Gandhi.
The problem of having uniform temperature in the furnace is important during tempering, where the mode of heat transfer is by convection.
"Even,if you are a minority of one, truth is the truth."
Mahatma Gandhi.
EdStainless
Materials
We used to use 1 hr plus 1 hr for the first inch and 30 min for each additional.
So 8" would be 1+1+(7*0.5)=5.5 hr
and 4" would be 1+1+1.5=3.5hr
But even for thin parts we never went below 2hr.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
So 8" would be 1+1+(7*0.5)=5.5 hr
and 4" would be 1+1+1.5=3.5hr
But even for thin parts we never went below 2hr.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
- Thread starter
- #5
My information is from ASME BPV Code committee work and
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1
- #7
tamal1475 ...
Recommend that You review at AMS-H-6875 [was MIL-H-6875] Heat Treatment of Steel Raw Materials ... Last few pages deal with tempering soak time based on thickness, various types of steels. There is also an illustration showing how configuration [plate, bar, hollow, etc] relates to the concept of 'thickness' for this aspect of HT.
Also suggest You review latest versions of following specs for some insight, this subject...
AMS2750 Pyrometry
AMS2759 Heat Treatment of Steel Parts, General Requirements
AMS2759/1 Heat Treatment of Carbon and Low-Alloy Steel Parts Minimum Tensile Strength Below 220 ksi
AMS2759/9 Hydrogen Embrittlement Relief (Baking) of Steel Parts
AMS2759/11 Stress Relief of Steel Parts
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
Recommend that You review at AMS-H-6875 [was MIL-H-6875] Heat Treatment of Steel Raw Materials ... Last few pages deal with tempering soak time based on thickness, various types of steels. There is also an illustration showing how configuration [plate, bar, hollow, etc] relates to the concept of 'thickness' for this aspect of HT.
Also suggest You review latest versions of following specs for some insight, this subject...
AMS2750 Pyrometry
AMS2759 Heat Treatment of Steel Parts, General Requirements
AMS2759/1 Heat Treatment of Carbon and Low-Alloy Steel Parts Minimum Tensile Strength Below 220 ksi
AMS2759/9 Hydrogen Embrittlement Relief (Baking) of Steel Parts
AMS2759/11 Stress Relief of Steel Parts
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
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