FAQ

HcHCr stands for High-Carbon, High-Chromium — the Indian and Asian market name for AISI D2, a cold-work tool steel widely used for its outstanding wear resistance and dimensional stability during heat treatment.

D2 contains 1.40–1.60% Carbon, 11.00–13.00% Chromium, 0.70–1.20% Molybdenum, 0.50–1.10% Vanadium, 0.10–0.60% Manganese, and 0.10–0.60% Silicon. The high carbon and chromium contents create large volumes of hard carbides responsible for its exceptional abrasion resistance.

Chromium forms hard carbides that give D2 its wear resistance, provides mild corrosion resistance (semi-stainless), and enables air hardening — which improves dimensional stability during heat treatment.

In the annealed condition D2 reaches 217–255 HB. After hardening it achieves 58–62 HRC with a tensile strength of approximately 1900 MPa and a compressive strength exceeding 2700 MPa. Density is 7.70 g/cm³.

D2 is the benchmark for cold-work abrasion resistance. A2 offers roughly half the wear resistance of D2, while O1 is around 30%. H13 is lower still, as it is designed for hot-work applications. PM grades like CPM D2 exceed standard D2 due to finer carbide distribution.

D2 offers mild corrosion resistance and is sometimes called semi-stainless, but it will rust if exposed to moisture. Always clean, dry, and oil D2 tools during storage. For aggressive corrosion environments, choose 440C or a powder metallurgy stainless grade instead.

D2 is air-hardening and shows minimal distortion, typically 0.05–0.08% expansion. This predictable behaviour makes it ideal for precision blanking dies, gauges, and close-tolerance tooling.

D2 is austenitized at 1010–1040 °C (1850–1900 °F). Lower temperatures in this range give better toughness (~58–60 HRC), while higher temperatures give maximum hardness (~61–62 HRC). Vacuum or controlled-atmosphere furnaces are strongly recommended to prevent decarburization.

D2 is air-hardening. Still air is sufficient for sections up to 75 mm; forced air or fan cooling is used for larger sections up to 150 mm. Pressurized gas in a vacuum furnace gives the best dimensional control for large or complex tooling. Temper immediately once the part cools to 50–70 °C — never allow it to reach room temperature first

D2 is widely used for blanking and piercing dies, drawing dies, forming tools, circular slitting knives, shear blades, precision gauges, powder compaction dies, and woodworking knives. Any cold-work application where abrasion resistance is the primary requirement is a strong candidate for D2.

D2 is suitable for wear plates and inserts where abrasive plastics such as glass-filled or mineral-filled resins are processed. It is not recommended for high-polish molds or corrosive resins — for those applications use S136, 1.2083, or 420SS.

D2 is very difficult to weld due to its high carbon and chromium content. It should only be attempted for die repair by experienced welders. Preheat to 300–400 °C, use a matching filler rod, maintain interpass temperature above 260 °C, and temper immediately after welding before the part cools to room temperature. Failure to do so almost always results in cracking.

Yes. D2 (AISI/SAE), HcHCr (India), 1.2379 / X155CrVMo12-1 (DIN/EN), SKD11 (JIS), BD2 (BS), and Kh12MF (GOST) are all equivalent designations. Minor compositional differences exist between standards, so always verify the chemistry against your specification before substituting one for another