Steel for steel cutting blades
We're a well drilling company that uses custom-built downhole casing cutters to cut off steel pipe below grade. The steel being cut is typically mild pipe steel, but can be stainless 304, or High Strength Low Alloy (HSLA) steel pipe.
The tools we're using were all built by machinists that have long passed away, and we find ourselves in the position of needing to get new blades built. These blades look like most pipe cutting blades (Reed MFG Products for example), but we don't know what metal was used to make them or how it was hardened.
We've taken the spare blades we have to a machine shop and they are recommending either H900 17-4 stainless for 42 HRC, heat treated tool steel for 50 HRC+, or destructive lab testing to verify.
I'm looking for input here for what steel product might be best used to build these blades. We could send in for destructive testing, but I'm thinking this is overkill - someone out there must know what a typical cutting blade would be made from.
Anyone?