Sure, let’s keep it tight. Grain growth in steel roughly follows the equation D²‑D₀² = k t, where D is the final grain size, D₀ is the initial size, k is a material‑specific rate constant, and t is time. If your current tempering keeps D at, say, 50 µm with k ≈ 0.02 µm²/s at the target temperature, you can halve the time to 50 % and still stay under 55 µm. In practice that means reducing the soak to about 10 minutes at 580 °C and pulling the furnace up and down faster—roughly 3 °C per second. Keep a close eye on the micro‑probe; any rise over 55 µm and you’re losing toughness. Stick to that schedule and you’ll stay on target.