Two parts can be machined to the exact same dimensions from the exact same steel, and one will last ten years while the other shears off in a month. The difference is heat treating. At Crawford Machine in Titusville, PA, heat treating is how we make sure the parts we build, especially the slips and reins we make for oil wells, hold up under real loads.
What heat treating is
Heat treating is a controlled process of heating steel to a specific temperature, holding it there, and then cooling it at a specific rate. Quenching (fast cooling in oil or water) makes steel hard. Tempering (reheating to a lower temperature) takes some of that hardness back out to make the part tougher and less brittle. Annealing softens metal so it can be machined. The combination of steps and temperatures determines the final hardness, strength, and toughness of the part.
Why hardness has to match the application
Every material shears, bends, or wears at a certain stress, measured in PSI. A part has to be hard enough to carry its load without deforming, but not so hard that it cracks under shock. Soft brass is easy to machine and fine for a plumbing fitting, but put a soft brass part in an oil well and it will wear out or shear off long before a properly hardened steel part would. Go too far the other way and an over-hardened part becomes brittle and snaps instead of bending. Picking the right hardness for the job is the whole game.
How we do it
We select the steel for the application, machine the part, heat treat it to the target hardness, and verify it with a hardness tester. Parts that carry pressure, like our slips and reins, are also pressure tested in-house before they leave the shop. That is why customers tell us our parts outlast the competition.
When you need it
Heat treating matters for anything that carries load, pressure, or impact: oil well tools, shafts, pins, dies, cutting edges, gears, wear plates, and replacement parts that keep failing. If a part you bought keeps breaking, the material or the heat treat is usually the reason, and we can often fix that.