High Compressive Strength Tool Steels for Plastic Deformation Resistance
In the plastic deformation failure mode, the working edge, forming surface, punch head, die corner, or cavity area yields under load. The tool may still look intact, but its geometry has changed, making it difficult to control part accuracy, clearance, and forming stability.
Tool Steels Available for Plastic Deformation Resistance
Aobo Steel supplies cold work, hot work, and high-speed tool steels for high-pressure dies, punches, forming tools, extrusion tooling, and applications where edge collapse or surface sinking must be controlled.
D2 | 1.2379 | SKD11
High-pressure cold work steel for wear resistance, edge stability, and deformation resistance.
D3 | 1.2080 | SKD1
High-hardness cold work steel for steady pressure and severe abrasive service.
D6 | 1.2436 | SKD2
Cold work grade for severe wear and pressure conditions where impact risk is controlled.
A2 | 1.2363 | SKD12
Balanced cold work steel when deformation resistance must be combined with better toughness.
Cr12MoV Tool Steel
GB cold work grade for general dies, forming tools, cutting tools, and pressure-resistant cold work applications.
O1 | 1.2510 | SKS3
Oil-hardening cold work steel for moderate-load tools, smaller dies, and shorter production runs.
O2 | 1.2842
Oil-hardening cold work steel for general tooling parts and moderate-pressure applications.
H11 | 1.2343 | SKD6
Hot work steel for pressure resistance, toughness, and elevated-temperature service.
H13 | 1.2344 | SKD61
Hot work steel for hot forging, die casting, hot extrusion, and hot shear tools.
M2 | 1.3343 | SKH51
High-speed steel for cold extrusion punches, cutting tools, and high-pressure special tools.
To reduce this failure, high-compressive-strength tool steels such as D2, D3, D6, A2, and Cr12MoV are selected for cold work applications requiring high hardness, compressive strength, and resistance to surface collapse or edge rounding.
When the same deformation problem arises at elevated temperatures, H11 and H13 are chosen. In hot forging, die casting, hot extrusion, or hot shearing, the steel must simultaneously resist both pressure and softening.
In actual tooling, plastic deformation usually appears as edge rounding, surface sinking, punch mushrooming, die corner collapse, cavity distortion, or unstable clearance. This failure is different from normal abrasive wear because the tool is not only losing material but also changing its working geometry.
Plastic deformation results from low hardness, insufficient compressive or hot strength, or excessive pressure. If chipping or cracking occurs first, toughness, not hardness, may be needed.
Recommended High-Compressive-Strength Tool Steels
| Grade / Group | Equivalent Grades | Best Use Direction | Limitation |
|---|---|---|---|
| D2 | 1.2379 / SKD11 / Cr12Mo1V1 | High-pressure cold work tools needing wear resistance and deformation resistance | Not suitable for heavy impact |
| D3 | 1.2080 / SKD1 | High-hardness cold work tools under steady pressure | Lower toughness than D2 |
| D6 | 1.2436 / SKD2 | Severe wear and pressure conditions | Impact risk must be controlled |
| A2 | 1.2363 / SKD12 | Tools needing better toughness than D2 while still resisting deformation | Lower wear resistance than D2 and D3 |
| Cr12MoV | Chinese GB grade | General cold work dies, forming tools, and cutting tools | Performance depends strongly on heat treatment |
| O1 / O2 | 1.2510 / 1.2842 | Moderate-load tools, smaller dies, and shorter production runs | Not suitable for severe pressure |
| H11 | 1.2343 / SKD6 | Hot work tools needing pressure resistance and toughness | Not a cold work wear steel |
| H13 | 1.2344 / SKD61 | Hot forging, die casting, hot extrusion, and hot shear tools | Lower cold wear resistance than D-series steels |
| M2 / M4 | High-speed steels | Cold extrusion punches, cutting tools, and high-pressure special tools | Higher cost and more specific use |
| PM Tool Steels | PM cold work and PM high-speed grades | Very high hardness with improved carbide uniformity | Higher cost |
| Cemented Carbide | WC-Co grades | Extreme compressive load beyond tool steel capability | Poor tolerance for bending and impact |
D2 is usually the practical starting point for cold work deformation resistance. D3 and D6 move further toward wear and pressure resistance. A2 is useful when the tool also needs more toughness.
Cemented carbide is used only when tool steel cannot carry the pressure. Its room-temperature compressive strength ranges from 3,450 to 6,900 MPa, but it is much less tolerant of bending, impact, or poor support.
How to Choose Tool Steel for Plastic Deformation Resistance
| Working Condition | Better Material Direction |
|---|---|
| Cold work pressure with wear | D2 / D3 / D6 / Cr12MoV |
| Cold work pressure with chipping risk | A2 or lower-hardness D2 direction |
| Moderate pressure and lower production volume | O1 / O2 |
| Hot pressure above about 200 C | H11 / H13 |
| Severe cold extrusion or high-load punching | M2 / M4 / PM tool steel |
| Pressure exceeds steel capability | Cemented carbide or tool redesign |
For cold extrusion, practical pressure limits are useful. Punch pressure is often kept below about 2,370 MPa, and die internal pressure below about 1,895 MPa. When the working pressure approaches these levels, grade selection should be checked together with tool geometry, backing support, and contact area.
PM steels are useful when conventional high-alloy steels cannot provide sufficient hardness and toughness simultaneously. Some PM grades can reach about 64-69 HRC while keeping a finer carbide structure than conventionally produced steels.
Common Applications of High Compressive Strength Tool Steels
| Application | Common Grade Direction | Main Requirement |
|---|---|---|
| Blanking punches and dies | D2 / D3 / D6 / Cr12MoV | Edge stability and wear resistance |
| Coining tools | D2 / D6 / M2 | Resistance to surface sinking |
| Thread rolling dies | D2 / M2 / PM steels | Pressure resistance and dimensional stability |
| Cold extrusion punches | D2 / M2 / M4 / PM steels | High compressive strength with controlled toughness |
| Deep drawing dies | D2 / A2 / Cr12MoV | Stable die geometry |
| Cold heading tools | D2 / A2 / M2 | Compression resistance with toughness |
| Powder compaction dies | D2 / D6 / PM steels / carbide | High pressure and abrasive wear resistance |
| Forming rolls | D2 / D6 / Cr12MoV | Surface stability and wear resistance |
| Hot forging dies | H11 / H13 | Hot strength and thermal fatigue resistance |
| Die casting dies | H13 / H11 | Heat resistance and pressure resistance |
| Hot extrusion tools | H11 / H13 / H21 direction | Hot compressive strength |
When High Compressive Strength Is Not Enough
| Problem | Selection Meaning |
|---|---|
| Cracking or chipping first | High compressive strength is ineffective if cracking or chipping occurs before deformation. In such cases, A2, S7, or lower-hardness steels may prolong tool life compared to hard D-series steels. |
| Pressure with heat | D2, D3, D6, and Cr12MoV can resist cold pressure, but they lose strength as the temperature rises. H11 and H13 are better choices when high-temperature hot working is combined with pressure. |
| Local overload | If the tool still deforms after correct material selection and heat treatment, the load may be too concentrated for the working area. This usually requires better backing support, a larger contact area, improved radius design, or a material upgrade to PM steel or cemented carbide. |
Need Tool Steel for High-Pressure Dies or Forming Tools?
Aobo Steel supplies tool steel round bar and flat bar for high-pressure dies, forming tools, extrusion punches, and hot work applications. Send your required grade, size, quantity, and application.