controlled_burn
Plastic
- Joined
- Mar 25, 2019
I have a bend mandrel that I'm working on, and it's machined from annealed A-2 (purchased from Bohler Uddelholm with test reports). All of the machining is complete, and it has been sent out to be heat treated to 62 HRC. Fast forward to now, the part came back with a rusty layer on it, and it's definitely not 62 HRC. The surface rust made me raise my eyebrows, so I hit it with a file and the file dug right in with relatively light pressure. I also have parts (heat treated by the same company) that are truly 58-60, and the file just skates right off the surface; there's a night and day difference.
So I have contacted the heat treater that I used, and they told me it had to be heat treated three times, with a final freeze quench as they struggled to get it to 58 the first few times. At this point, I'm assuming this part hasn't even been tempered. It's "as quenched" right now, but there's still no way it's 58. From what I know, A-2 should be able to get up to 64 HRC, so I don't see how they struggled to get 58 (if the part even is that hard).
Has anyone else had this experience with A-2? I'm just wondering what to do next since I need to use this part, but I need it hard. The paperwork that came back with this part claimed that it was 58 HRC, but I'm thinking of having someone else test it for a second opinion. My final questions are:
1. If it is hard, just not 58, what should I do with it? Full anneal? Sub anneal? I need it to be at least 60 HRC. I'm also going to go to a different heat treater with a better reputation.
2. Is there any risk in bringing it to full soft and then hardening it again? Greater risk of cracking?
Any advice is greatly appreciated. The part dimensions are roughly 2"x2"x16" and care was taken to machine the part leaving no sharp corners/edges.
So I have contacted the heat treater that I used, and they told me it had to be heat treated three times, with a final freeze quench as they struggled to get it to 58 the first few times. At this point, I'm assuming this part hasn't even been tempered. It's "as quenched" right now, but there's still no way it's 58. From what I know, A-2 should be able to get up to 64 HRC, so I don't see how they struggled to get 58 (if the part even is that hard).
Has anyone else had this experience with A-2? I'm just wondering what to do next since I need to use this part, but I need it hard. The paperwork that came back with this part claimed that it was 58 HRC, but I'm thinking of having someone else test it for a second opinion. My final questions are:
1. If it is hard, just not 58, what should I do with it? Full anneal? Sub anneal? I need it to be at least 60 HRC. I'm also going to go to a different heat treater with a better reputation.
2. Is there any risk in bringing it to full soft and then hardening it again? Greater risk of cracking?
Any advice is greatly appreciated. The part dimensions are roughly 2"x2"x16" and care was taken to machine the part leaving no sharp corners/edges.