Tool Steel Selection for Hot Forging, Stamping & Trimming Dies
Select tool steel by operating temperature, thermal fatigue, hot wear, shock load, trimming severity, and cooling conditions. For hot forging, hot stamping, and hot trimming dies, the main choice is usually between hot toughness, heat checking resistance, hot hardness, and abrasion resistance. Trimming-specific grade choices are in the hot trimming die steel selection guide.
Quick Selection Guide by Tool Steel Grade
Choose the grade according to whether the tool is used for hot forging dies, hot stamping dies, trimming blades, trimming punches, or severe high-temperature applications. The press-hardening (hot stamping) case is covered separately on the hot stamping die steel selection page.
Hot Forging Dies
H13 Tool Steel
1.2344 / SKD61
Recommended for hot forging dies, inserts, and general hot-work tooling under repeated heating and cooling cycles.
Reason: H13 gives a strong balance of toughness, deep hardenability, thermal fatigue resistance, and resistance to heat checking.
Shock & Toughness
H11 Tool Steel
1.2343 / SKD6
Recommended for hot forging dies, inserts, hot trimming punches, and severe trimming tools where toughness is critical.
Reason: H11 provides high toughness and resistance to high-temperature impact loading, helping reduce cracking and snapping risk.
Higher Hot Hardness
H21 Tool Steel
1.2581 / SKD5
Recommended for high-temperature hot forging and heavy hot trimming applications where hot hardness is the main requirement.
Reason: H21 contains high tungsten, giving stronger resistance to softening at elevated temperature, but it is less suitable for severe water cooling.
Large Die Blocks
L6 Tool Steel
1.2714 / SKT4
Recommended where hot forging die blocks need strong shock resistance under heavy impact.
Reason: L6 is a tough low-alloy die steel option for applications where impact toughness is more important than maximum hot wear resistance.
Hot Trimming Blades
D2 Tool Steel
1.2379 / SKD11 / Cr12Mo1V1
Recommended for hot trimming die blades and bottom cutting edges where abrasive scale wear is severe.
Reason: D2 provides strong abrasion resistance for cutting hot forging scale, but it should be used where edge chipping risk is controlled.
Trimming Balance
A2 Tool Steel
1.2363 / SKD12
Recommended for hot trimming blades when a better balance of wear resistance, toughness, and dimensional stability is required.
Reason: A2 is used for hot trimming where the tool needs more toughness than D2 while still keeping useful abrasion resistance.
Selection Summary
This table gives a faster comparison when the buyer already knows the die application and main working condition.
| Die Application | Main Requirement | Aobo Steel Grades |
|---|---|---|
| General hot forging dies and inserts | Toughness, deep hardenability, thermal fatigue resistance, and heat checking resistance | H13, H11 |
| High-temperature forging above severe hot-work conditions | Hot hardness and resistance to softening at elevated temperature | H21 |
| Large forging die blocks and heavy impact work | Shock resistance and impact toughness | L6 |
| Hot stamping dies for heated sheet forming | Wear resistance, hot-work toughness, and heat extraction support | H13, H11 |
| Hot trimming blades and bottom cutting edges | Abrasion resistance against hot scale | D2, A2 |
| Hot trimming punches or severe thick flash trimming | Extreme toughness and heat resistance over pure wear resistance | H11, H13, H21 |