The Mystery of ASTM A487 Grade 4 Pressure Service Castings
The Mystery of ASTM A487 Grade 4 Pressure Service Castings
(OP)
Table 1 of ASTM Grade 4 Class A, B, C, D pressure service castings all indicate the same required heat treatment:
Austenize at 1600F,
Media: air or liquid
Quenching Cool Below 500°F
Tempering Temperature: 1150°F
Question 1:
There seems to be some steps missing, such as
a. holding time at austenize temperature,
b. are we to air cool or furnace cool until we reach
500°F and then quench ?
c. how long to hold at the tempering temperature?
Table 3 lists a variety of TS/YS combinations:
Class A – 90ksi UTS, 60ksi YS
Class B – 105ksi UTS, 85ksi YS
Class C – 90ksi UTS, 60ksi YS
Class D – 100ksi UTS, 75ksi YS
Question 2:
How does the same heat treatment of Table 1 result in different TS/YS when all classes of Grade 4 have the same chemistry as shown in Table 2?
Question 3:
This A487 in any of its classes doesn't seem to be much different than normalized 4130. What is the advantage?
Thanks for any insight
Austenize at 1600F,
Media: air or liquid
Quenching Cool Below 500°F
Tempering Temperature: 1150°F
Question 1:
There seems to be some steps missing, such as
a. holding time at austenize temperature,
b. are we to air cool or furnace cool until we reach
500°F and then quench ?
c. how long to hold at the tempering temperature?
Table 3 lists a variety of TS/YS combinations:
Class A – 90ksi UTS, 60ksi YS
Class B – 105ksi UTS, 85ksi YS
Class C – 90ksi UTS, 60ksi YS
Class D – 100ksi UTS, 75ksi YS
Question 2:
How does the same heat treatment of Table 1 result in different TS/YS when all classes of Grade 4 have the same chemistry as shown in Table 2?
Question 3:
This A487 in any of its classes doesn't seem to be much different than normalized 4130. What is the advantage?
Thanks for any insight





RE: The Mystery of ASTM A487 Grade 4 Pressure Service Castings
This means you air or liquid cool to below 500 deg F before tempering.
1 hour/inch at temperature.
Different cooling rates, air versus liquid, and tempering temperatures 1100 deg F versus 1150 deg F results in different properties for the specific class.
Do not understand your question because this specification is for castings, not wrought material.
RE: The Mystery of ASTM A487 Grade 4 Pressure Service Castings
Question 2 relates back to the fact that both specified temperatures are minimums. You would heat treat different grades (A and C vs B and D, in particular) differently despite the fact that you could have poured the castings with the same chemistry. Obviously, your quench method in coming down from the austenitizing temperature will have a big effect on properties.
Question 3. This standard is for steel castings suitable for pressure service. You can choose to reference it when purchasing steel castings that are going into pressure service. You could also choose to order castings using your own specifications instead.
RE: The Mystery of ASTM A487 Grade 4 Pressure Service Castings
If you need to use 4130 or similar grade,you could specify the properties you need keeping in mind that you are dealing with cast test bars now.