HeatTreatBench: Knife Steels

HeatTreatBench is a focused, offline reference and logbook for knifemakers who heat-treat their own blades. Pick a steel, dial in a target hardness, and get a clear starting recipe: austenitize temperature, soak time, quench medium, whether cryo is needed, and the temper temperature, time and cycles for that hardness. No account, no cloud, no tracking. Buy once, use it forever, at the forge with no signal. WHAT IT DOES - Curated steel database. A hand-built dataset covering popular knife steels across carbon, low-alloy, stainless and powder-metallurgy / tool grades (1084, 1095, 80CrV2, W2, AEB-L, 14C28N, CPM-3V, D2 and more). Every steel shows austenitize, soak, quench, cryo, and temper guidance. - Target-hardness recipe engine. Choose your target HRC and the recipe updates to the matching temper temperature. Values between data points are interpolated and labelled as such; the app never extrapolates past a steel's reliable range - if you ask for a hardness outside the data, it tells you so instead of inventing a number. - Hardness to temper table. See how target HRC maps to temper temperature so you can trade hardness for toughness depending on the blade's job. - Soak and temper timers. Lock-screen countdowns that keep running with the screen off and alert you when the soak or each temper cycle is done, including a reminder to cool to room temperature between cycles. Fully on-device, no push server. - Tempering oxide color reference. A wide-color (P3) chart of carbon-steel temper colors with approximate temperatures. Clearly marked as a visual reference only - thin-film interference colors are affected by screen brightness, ambient light and display age, and are not a measurement of temperature or hardness. - Blade log. Record every blade you run: steel, as-run furnace temperature, soak, quench, temper, measured HRC, outcome and notes. Repeat your wins and diagnose the failures. You can scan a hardness-tester reading with the camera (on-device text recognition) to save typing - the value is always editable. - PDF export. Export a single-page heat-treat record for any blade to save, print or share. Everything stays on your device. EVERYTHING OFFLINE, NOTHING COLLECTED The whole app works in airplane mode. There is no account, no sign-in, no analytics and no advertising. Your blade log, photos and notes never leave your device, and the camera is used only for on-device reading of a hardness number you choose to scan. DATA SOURCING AND DISCLAIMER Every recipe is a reference starting point compiled from published, authoritative sources (manufacturer datasheets and well-documented maker practice) and cross-checked in a research-style review. The in-app Source label tells you where each recipe comes from. These numbers are NOT a guarantee of results. Heat-treat outcomes vary with your furnace, quenchant, blade geometry and process. Always verify on your own setup, follow proper safety practice for high temperatures and cryogenic media, and treat the app as a reference - not professional or metallurgical advice, and not a measurement instrument. The temper color chart in particular must never be used as a way to measure temperature or hardness. One-time purchase. No subscription. No account. Works 100% offline.