Through-hardening
Normalize, quench and temper, austemper, martemper and the 17-4 PH conditions — transformations that set the strength and toughness of the whole section.
8 treatments compared
Cycle temperature, the hardness each delivers, furnace time and relative cost, side by side. Open a treatment for its full cycle, specifications, compatible alloys and drawing call-out.
| Treatment | Temperature | Hardness | Cycle time | Relative cost |
|---|---|---|---|---|
Normalizing heats steel above its critical range and cools it in air. | 815–955 °C | 120–250 HB | 3–8 h | $ Budget |
Quench and temper transforms hardenable steel to martensite and then tempers it to the required balance of strength and toughness. | 815–900 °C | 28–55 HRC | 4–10 h | $$ Standard |
Q+T H900 is a precipitation-hardening condition for 17-4 PH (S17400) and 15-5 PH (S15500). | 477–493 °C | 40–47 HRC | 2–5 h | $$ Standard |
Q+T H1025 is a precipitation-hardening condition for 17-4 PH (S17400) and 15-5 PH (S15500). | 546–566 °C | 35–42 HRC | 5–9 h | $$ Standard |
Q+T H1075 is a precipitation-hardening condition for 17-4 PH (S17400) and 15-5 PH (S15500). | 574–585 °C | 33–39 HRC | 5–9 h | $$ Standard |
Q+T H1150 is a precipitation-hardening condition for 17-4 PH (S17400) and 15-5 PH (S15500). | 616–627 °C | 28–37 HRC | 5–9 h | $$ Standard |
Austempering forms bainite by quenching austenitized steel or ductile iron into a hot bath and holding isothermally. | 790–900 °C | 25–55 HRC | 4–10 h | $$$ Premium |
Martempering is an interrupted quench that equalizes austenitized steel just above its martensite-start temperature before cooling through martensite formation. | 790–900 °C | 35–62 HRC | 4–9 h | $$$ Premium |
Ranges depend on the alloy and the specification called out. A dash means the treatment sets no target for that value.
Where through-hardening sits
Cycle temperature against hardness delivered across the heat-treatment library. Other families appear as faint dots. Click a dot to open its page.
1 of the 8 treatments here has no hardness delivered figure and is not placed.
Choosing between them? How to choose a heat treatment — best picks by what the part needs, the five things a drawing call-out must carry, and the questions engineers ask.