I am mostly clueless here, and need some basic hints. Steel materials properties are simply too complex to be modeled easily. First-hand experience is clearly needed.
I must select a steel alloy, but I was a physics major, so I am lost in an endless twisty maze of stress-strain curves, Young's modulus numbers, and conflicting tensile strength claims.
All I need to do is to narrow down my choices to a few commonly-available non-exotic commodity alloys, and then rationalize costs against strength.
The goal is to create a simple flat "pry bar" hand tool that will be no longer than 7 to 10 inches, and no wider than 1 to 2 inches. A minimum thickness of 11 gauge "seems reasonable", but thicker would not be a problem. A dull edge will need to be ground on the "blade", and this edge will do all the prying. (The "edge" is to allow the part to force open narrow gaps.)
I understand laser-cutting prototypes and then stamping production units. Drop-forging is something I have only heard of, and I have no idea if it is economical for production runs in the hundreds, rather than hundreds of thousands.
I looked at my own tools for good examples of the kind of stress-strain and corrosion-resistance I need, and found:
CIRCA 1977 STANLEY THIN CROWBAR (roughly 11 gauge) Made from a high nickel alloy, but has some surface rust. Clearly made from sheet stock, and then formed into a "squished S curve" to make it a "crowbar".
SEARS CRAFTSMAN CRESCENT WRENCH A forged part, said to be made of 4620 alloy.
SNAP-ON-TOOLS CRESCENT WRENCH Another forged part, said to made of 4140 alloy and then coated to avoid corrosion
SOCKET WRENCHES AND EXTENSION BARS These are said to be made of 4037 and 4137 alloys
Other Alloys that have been mentioned in the course of my research include 4130 and 6150.
Specific "corrosion resistant" alloys have also been mentioned, including 4340, 4320, and 4620.
My problems are narrowing down choices to find the optimal trade-offs between:
a) Good resilience/stress-strain, as a pry-bar that bends is useless.
b) Non-salt, non-acid, "normal outdoor exposure" corrosion resistance, as powder coats will abrade off over time, and 3xx 4xx "stainless steels" appear to both lack the required strength and are too costly. (A high-strength stainless steel would be "excellent", if it were affordable, but the communist Chinese appear to be buying up so much steel that I'm not sure we can afford "stainless".)
c) Cheap to make in 100s, maybe a thousand per batch at the most. I know that tooling for stamping would be less than $2K for a part this simple, but the stamping company appears clueless about materials, and the laser-cutting shop thought that 11 gauge 304 stainless was a "good choice", until I had them cut a sample, and bent it into a curve with my bare hands before their eyes.
So, any clues for the utterly clueless?
I had hoped to contract out:
a) Cutting the part from 48" x 96" sheets a1) With a laser cutter, or a2) By stamping
b) Remove burrs, grind the "edge", and polish a smooth finish on the surfaces
c) Tempering? This is where things get scary, as the failure mode wants to be "bend before shatter", but bending is exactly what we want to resist, up to and including putting one's foot on the pry bar, and stomping on it when trying to pry apart nailed wood.
But drop-forging is not out of the question, if this is a "must".
Thanks!
jim ( snipped-for-privacy@gmail.com)