Heat treatment guidance for tool steel, by grade.
Austenitizing, quenching and working-hardness references for cold work, hot work, high speed, stainless and bearing steels, along with the fundamentals that keep distortion and cracking under control. Read the guide you need, or send specs for a bulk supply quote.
Cold Work
Wear-resistant grades for blanking, forming and cutting at room temperature.High-carbon high-chromium cold-work steel. Air hardening keeps distortion low while delivering excellent wear resistance for long production runs.
High-wear cold-work steel for long-run blanking and forming. Oil hardening reaches very high hardness but calls for care to avoid quench cracking.
Tungsten-alloyed cold-work steel with fine, stable carbides that hold a keen edge in cutting and trimming tools.
Air-hardening cold-work steel that balances wear resistance and toughness, with better dimensional stability than oil-hardening grades.
General-purpose oil-hardening tool steel, easy to machine and forgiving in the shop, a reliable choice for short to medium runs.
Manganese oil-hardening steel with low distortion on quench, well suited to gauges and precision tooling.
Shock-Resisting
Tough grades for tooling under heavy impact and shock loads.Tungsten shock-resisting steel for impact tools that also need moderate wear resistance. Often tempered immediately after quench to prevent cracking.
Air-hardening shock-resisting steel with high toughness and deep hardenability for dies that take repeated heavy impact.
Hot Work
Grades that hold strength and resist thermal fatigue at elevated temperatures.Chromium-molybdenum hot-work steel with strong resistance to thermal softening, used for hot punches, extrusion tooling and inserts.
Air-hardening hot-work steel with deep hardenability and high toughness for die casting, extrusion and forging dies.
The workhorse hot-work grade, combining thermal-fatigue resistance with toughness for die casting, forging and extrusion dies.
High Speed
Red-hard grades for cutting tools that run hot and fast.Versatile high-speed steel with a strong balance of wear resistance and toughness for drills, taps and cutting tools.
Stainless
Corrosion-resistant grades for molds, blades and wear parts in wet or hygienic environments.High-carbon martensitic stainless steel that reaches high hardness while resisting corrosion, used for bearings, knife blades and wear parts.
Corrosion-resistant martensitic stainless steel with good polishability, widely used for plastic molds and blades that run in humid or corrosive conditions.
Bearing & Other
Specialist grades for bearings and shock-loaded forging tooling.High-carbon chromium bearing steel for components that need high hardness and good wear resistance, such as rollers and races.
Nickel-chromium tool steel with high toughness and good hardenability for shock-loaded dies and large forging tooling.
Heat treatment, in four steps
Heat treatment is controlled heating and cooling that changes microstructure and properties while limiting shape change. The chain runs preheat, austenitize, quench and temper, and the final result is set by its weakest link, above all furnace uniformity, part geometry and quench severity.
Process chain
- Preheat reduces thermal shock and lowers the risk of cracking.
- Austenitize dissolves carbides to enrich the austenite with carbon and alloying elements.
- Quench suppresses pearlite and bainite to form martensite.
- Temper restores toughness and controls retained austenite.
Common risk factors
- Distortion Comes from residual stress, thermal gradients and the volume change of phase transformation.
- Quench cracking Rises with sharp corners, high tensile stress and excessive quench severity.
- Retained austenite May need multiple tempers or cryogenic treatment in high-alloy grades.
- Decarburization Comes from non-neutral atmospheres; protective atmospheres or vacuum furnaces help.
Aobo Steel supplies tool steel in the annealed condition, ready for you to machine and heat treat. The process ranges here are drawn from established metallurgical standards, international grade data and long-term industry practice, and reflect real operational feedback from forging, die-making and production users. Heat treatment itself is carried out on your side, so this guidance is offered as a reference to support that work. Because tool performance comes from many factors, with heat treatment just one stage whose outcome is further shaped by furnace control, part geometry and quench, these ranges are best read as a starting point and confirmed for your own parts.
Send your specs, get a clear answer
Tell us the grade, dimensions and quantity, or describe the tool you are making. Aobo Steel supplies tool steel in bulk to distributors, stockists and importers, with quality control and technical support behind every order.