I want to use a press and flare collets out made from low alloy steel 110 MYS 36 RC 1250 tempering temperature. We are using a flaring mandrel at 100F below tempering temperature and holding until cools till about 900F or 13 minutes. Flared collets do not spring back. I want to try and do this at a cooler temperature like 500F or 750F. I think I will work harden the material.
We have had the part micro structurally examined in several cross sections - axial and transverse plane at the bending area. The specimens come back showing tempered martensite. It is the same structure the base material has when examined without flaring.
I have heard some machine shops say they can do this at 407F and the parts pass muster but they will not let us watch process. If the wall is .200" thick, would you see cold worked microstructure that is in the shape of the bending when pressed out?
I'm trying to come up with a flaring procedure for this part and the only time I have seen a problem is when the part was QPQ'd prior to flaring. In that case the induction heated zone at the edm slot collet became very hot and looked molten. MPI revealed cracking along the collet fingers.
The parts are all induction heated in a 1" zone. Some temps are measured with laser and get so hot they have to flare within two minutes. Another shop has a water cooled induction heater and they can hold the material temperature for 10 minutes before flaring.
I have attached a drawing of the part and mandrel and some of the steps we call out. I am out of my element and trying to learn. It just seems to me that cold working must occur, even at the higher temps. However, it doesn't seems to catch the eye of two different metallurgical labs. As long as we see tempered martensite and no cracks during MPI we qualify the vendor to make the parts. I compare the pictures of the structure and can't tell a difference. What should I be looking for? Is there anything else these labs should be checking. They do check hardness. It is 300 Vickers.
Thoughts?
Do you think cooling to room temperature while flared has a large effect on Final OD.
Note: I believe we do this instead of cutting a part with OD to size and clamping down on fingers because we need the EDM slots to close so a ball can land on seat and seal. I think of you machined the angled cut and the tolerance was off the Flex Seat would not close or would close too soon and not fit into part. Don't really know Tribal knowledge that left with people who started company.
- CJ
We have had the part micro structurally examined in several cross sections - axial and transverse plane at the bending area. The specimens come back showing tempered martensite. It is the same structure the base material has when examined without flaring.
I have heard some machine shops say they can do this at 407F and the parts pass muster but they will not let us watch process. If the wall is .200" thick, would you see cold worked microstructure that is in the shape of the bending when pressed out?
I'm trying to come up with a flaring procedure for this part and the only time I have seen a problem is when the part was QPQ'd prior to flaring. In that case the induction heated zone at the edm slot collet became very hot and looked molten. MPI revealed cracking along the collet fingers.
The parts are all induction heated in a 1" zone. Some temps are measured with laser and get so hot they have to flare within two minutes. Another shop has a water cooled induction heater and they can hold the material temperature for 10 minutes before flaring.
I have attached a drawing of the part and mandrel and some of the steps we call out. I am out of my element and trying to learn. It just seems to me that cold working must occur, even at the higher temps. However, it doesn't seems to catch the eye of two different metallurgical labs. As long as we see tempered martensite and no cracks during MPI we qualify the vendor to make the parts. I compare the pictures of the structure and can't tell a difference. What should I be looking for? Is there anything else these labs should be checking. They do check hardness. It is 300 Vickers.
Thoughts?
Do you think cooling to room temperature while flared has a large effect on Final OD.
Note: I believe we do this instead of cutting a part with OD to size and clamping down on fingers because we need the EDM slots to close so a ball can land on seat and seal. I think of you machined the angled cut and the tolerance was off the Flex Seat would not close or would close too soon and not fit into part. Don't really know Tribal knowledge that left with people who started company.
- CJ
