Heat Treatment
Heat Treatment
(OP)
Is Quenching & Tempering a permissable alternative to Normalizing?
bearing in mind that the plates in question will be subject to fabricaton (rolling & welding) subsequently stress-relieving.
Cheers
bearing in mind that the plates in question will be subject to fabricaton (rolling & welding) subsequently stress-relieving.
Cheers





RE: Heat Treatment
Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!
RE: Heat Treatment
A516 Gr. 60
b)
Loss of tempering effect; I see where you are coming from please note SAW will be employed after rolling the plates. Is that another concern?
RE: Heat Treatment
BUT, hardening (quenching) temps. are lower than normalizing temps., and you will not get the same amount of microstructure refinement-if that's a concern.
RE: Heat Treatment
a)
The quenching medium is water
b)
The quenching temperature is about 1652 F
c)
The tempering temperature is about 1160 F
d)
The thickness is 1.35"
With appreciation,
RE: Heat Treatment
For my understanding though, I would love to know why you need to substitute NR with Q&T? Is it client requirement or restriction of the heat treatment facilities etc.?
Metalguy,
Finer pearlite and coarser microstructure by Q&Ting as compared to NRing----- What would be the impact on the mechanical properties
Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!
RE: Heat Treatment
Fine pearlite is almost always preferred-better mech. properties, except for creep (IIRC).
RE: Heat Treatment
RE: Heat Treatment
Would it worthwhile to conduct tensile testing with the following provisions:
1. Cut the specimen at the area of concern (neck of the tensile specimen), join it by SAW, back chip on other side and place a SMAW weld. (typical to main weld seams of the Pressure Vessel)
2. Preform item 1) in addition to stress releiving; prior
to tensile testing.
3. Machine the tensile specimen at mid-section (thickness)
with provisions for item 1) & 2) above.
4. Conduct hardness reading across the plates through thickness.
Or perhaps just reject the plates :)
b)
As for exchanging Q&T with Normalizing; I was worried about a lower grade material being used. But the tempering temperature is so high that any hardening effect would not be that substantial and I am concerned of why Q&T has been preformed seems more of a hassle.
With Appreciation
RE: Heat Treatment
You could also mount,polish and etch a piece and see what microstructure you have.
RE: Heat Treatment
2) The minimum Design Metal Temperature is 0°C (Design T.427°C Max.)as per our class.
3) According to ASTM A515 para.5 (2in and under in thickness mat be ordered normalized or stress relieved, or both).
4) Following to B31.3 Fig.323.2.2A (curve B) it is necessary to impact tested this material.
My question is: the material must be stress relieved or normalized.
Thank you for your help.
Ellynn
RE: Heat Treatment
Generally one would only do this if the material were thick - on the order of 3" or greater to meet ASME Code impact properties at -50 F.
RE: Heat Treatment
The heat treating requirements of A-672 apply to the pipe after forming and welding. Class 22 requires uniformly heating the pipe within the post weld heat treatment temperature range for a minimum of 1 hr per inch of thickness or 1 hr, whichever is greater. In order to assure meeting the toughness requirements of FIG. 323.2.2A Curve B, I would advise that the pipe be ordered as Class 42 - normalized and tempered. The impact test properties may also be met by manufacturing A-672 pipe from A-515-60 plate, previuosly normalized, followed by tempering per Class 22 as stated above.