Material is 20MNCr5 +HH+FP
Parts are Carburized, hardened and tempered, then Hard Turn several dimensions with Coolant. From the machining operation they go into a washer that in the rinse has a rust preventative.
The rust preventative is good for at least 30 days, we have parts some of these parts that have are 60days old from the washing date that have NOT shown rust. But we have others that after 2 weeks start showing Rust
just on the machined (hard turned) surface. Previous experience all Hard turning has been done dry, but for tool life the mechanical engineer does this with coolant. The rust starts as very small spots that then grow over 1-3 weeks. Anyone have any experience with this material and or Hard turning with coolant. Need to find the issue concerning the rust as the reworking of these parts is getting expensive.
Thanks
Parts are Carburized, hardened and tempered, then Hard Turn several dimensions with Coolant. From the machining operation they go into a washer that in the rinse has a rust preventative.
The rust preventative is good for at least 30 days, we have parts some of these parts that have are 60days old from the washing date that have NOT shown rust. But we have others that after 2 weeks start showing Rust
just on the machined (hard turned) surface. Previous experience all Hard turning has been done dry, but for tool life the mechanical engineer does this with coolant. The rust starts as very small spots that then grow over 1-3 weeks. Anyone have any experience with this material and or Hard turning with coolant. Need to find the issue concerning the rust as the reworking of these parts is getting expensive.
Thanks
