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17-4 ph cond h900 1
- Thread starter jergos
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Condition H900 is one hour @ 900F plus/minus 15F.
This means the metal temperature is at 900F when the clock starts. You can put the part into an oven that is at 900F from room temperature to minimize the metal heat up time. If your oven has circulation I would allow 15 min per in thickness to come up to temperature. If there is no circulation I would allow 25 minutes per inch of thickness if the oven is at 900F. I would not exceed 15 minutes on the clock.
Can you comeback with the size of your part with the thickness section?
If possible the end use as there are some caveats on using 17-4 PH H900.
This means the metal temperature is at 900F when the clock starts. You can put the part into an oven that is at 900F from room temperature to minimize the metal heat up time. If your oven has circulation I would allow 15 min per in thickness to come up to temperature. If there is no circulation I would allow 25 minutes per inch of thickness if the oven is at 900F. I would not exceed 15 minutes on the clock.
Can you comeback with the size of your part with the thickness section?
If possible the end use as there are some caveats on using 17-4 PH H900.
In addition to what was mentioned by unclesyd regarding time at temperature, now is as good of time as any to mention that furnace temperature surveys are important as is monitoring time at temperature.
I can't tell you how many times during audits I have requested the latest temperature survey of a heat treatment furnace and I receive a blank stare.
I can't tell you how many times during audits I have requested the latest temperature survey of a heat treatment furnace and I receive a blank stare.
- Thread starter
- #4
My problem is that I did heat up a little bit longer(2hours)a piece of 1.75" thick, hardness test gave me 38Hrc and hardness is not the same all around the piece.
Do you think that the fact I heated up to long could be the problem, or could my cooling process be part of the result?...
I cool up by opening about 2" wide the door of the oven en leaving piece in the oven.
End use of the the piece is a 20Tons tention Load cell to go on a crane. The crane is located off shore.
Do you think that the fact I heated up to long could be the problem, or could my cooling process be part of the result?...
I cool up by opening about 2" wide the door of the oven en leaving piece in the oven.
End use of the the piece is a 20Tons tention Load cell to go on a crane. The crane is located off shore.
I would not use this piece any where near a crane.
Your part will need to solution heat treated and re heat treated using the correct temperature, time, and cooling rate.
Before we go any further exactly how is the 17/4 part going to be used, like is it in tension or compression?
I personally would not use 17/4 @ H900 on any part of a lifting device especially offshore due to it's lower ductility and a higher degree of susceptibility to Chloride Stress Corrosion Cracking.
Your part will need to solution heat treated and re heat treated using the correct temperature, time, and cooling rate.
Before we go any further exactly how is the 17/4 part going to be used, like is it in tension or compression?
I personally would not use 17/4 @ H900 on any part of a lifting device especially offshore due to it's lower ductility and a higher degree of susceptibility to Chloride Stress Corrosion Cracking.
- Thread starter
- #6
The piece will be use in tension. Most Load cells from specialized manifacturer are made of 17-4, final condition can go from H900 to H1100 and H1150+1150... This depend on safety factors that has to be respected.
Load cells consist in measuring the deflection of the metal. Ductility has to be low to get good result. I know about the higher degree of susceptibility to Chloride Stress Corrosion Cracking, but how exactly can I control it?
What would be the stainless type you would use for such application.
Load cells consist in measuring the deflection of the metal. Ductility has to be low to get good result. I know about the higher degree of susceptibility to Chloride Stress Corrosion Cracking, but how exactly can I control it?
What would be the stainless type you would use for such application.
- Thread starter
- #7
I would look at Nitronic 50(High Strength). You might give HPA a call with your requirements.
The ductility of of Nitronic 50 (HS) is reduced based on the amount of cold work introduced in the metal. It also has better resistance to SCC than 17/4 SS
The ductility of of Nitronic 50 (HS) is reduced based on the amount of cold work introduced in the metal. It also has better resistance to SCC than 17/4 SS
EdStainless
Materials
I have seen 17-4 used for load cells, with a 20-1 (or greater) safety factor.
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Plymouth Tube
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Plymouth Tube
btrueblood
Mechanical
Syd posted the meta-link earlier, but the discussion of SCC is in this data bulletin:
see pages 13 and 14.
see pages 13 and 14.
EdStainless
Materials
I am sure that the ones that I worked with were aged at a higher temp. I didn't check the mechanicals but I seem to recall 1050F.
They were fully painted, either epoxy or powder coated.
And the safety factors were huge. We had one rated for 25T, it would take 100T without damage to calibration, and at 100T it still had a more than 4:1 factor. The material was never stressed to over 10% of the minimum yield strength.
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Plymouth Tube
They were fully painted, either epoxy or powder coated.
And the safety factors were huge. We had one rated for 25T, it would take 100T without damage to calibration, and at 100T it still had a more than 4:1 factor. The material was never stressed to over 10% of the minimum yield strength.
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Plymouth Tube
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