What steel

[Peter Simpson 3Participant @petersimpson3]

I would like to make some small pawls. The dimensions will be approx. 3/16″ wide x 1″ long and 1/2″ deep. I want to harden them once finished. Which steel would be the most suitable ?

[JasonBModerator @jasonb]

To through harden then Gauge plate (Ground flat stock) or you could mill the rectangular section from larger diameter silver steel.

If you just want the surface hard then mild steel such as EN3 flat bar will do for case hardening.

[FulmenParticipant @fulmen]

If you just need something that is generally hard and strong then any heat treatable steel will do. O1, spring steel, silver steel, chrome moly, whatever you can get your hands on. Even 8.8 ( and possibly 5/6.6) grade machine bolts will harden enough for undemanding work, but probably not for punches and cutting tools.

For thin, flat stock check out the knife smiths.

If you have a furnace then case hardening can be an option, although thin/complex parts are prone to warping and cracking.

 

[bernard towersParticipant @bernardtowers37738]

why. not make them of EN8 its easily hardened

[FulmenParticipant @fulmen]

As I said, anything that can be hardened. I don’t know too much about UK steels so I’ll leave the details as an exercise for the OP. For a more specific answer the OP should describe it’s use and what loads it will be subjected to.

Very roughly speaking there are two main classes of steels to consider; engineering steels and tool steels.

Engineering steels are though. Tensile strength is in the 500-1000MPa (70-150ksi) range and will bend before breaking. I believe the EN-series is in this category.
Tool steels are hard. Tensile strength from 1000 to 15000+MPa (150-220ksi). Tends to break before bending. This is stuff like O1, drill rod and silver steel.

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