Tool Steel Selection Reference

How to Select Tool Steels

This page is a practical reference for selecting tool steels by application, working condition, and required properties.

  • Find the tool application
  • Identify the working condition
  • Check the required property
  • Compare suitable grades
  • Confirm process limits
View Tool Steel Catalog Open Tool Steel Material Finder

1. Property Ratings of Common Tool Steels

The following charts compare common tool steels by relative property ratings. These values are useful for comparison, but they are not absolute mechanical test values.

Final performance still depends on steel quality, heat treatment, section size, tool design, and actual service conditions.

Abrasion Resistance

Higher value means stronger resistance to abrasive wear.
103
M4
100
D2
95
M2
65
A2
50
O1
48
A8
44
O6
44
S5
42
S7
30
H13

M4, D2, and M2 have the highest abrasion-resistance ratings in this comparison.

Toughness

Higher value means stronger resistance to cracking and impact failure.
103
S7
100
H13
90
S5
75
A8
40
A2
20
D2
20
M2
14
M4
14
O1
10
O6

S7, H13, and S5 have the highest toughness ratings in this comparison.

Machinability

Higher value means easier machining in tool manufacturing.
125
O6
90
O1
75
H13
75
S7
65
M2
65
S5
65
A2
60
A8
60
D2
60
M4

O6 and O1 are easier to machine than high-wear-resistance grades such as D2, M2, and M4.

Grindability

Higher value means easier grinding, finishing, and sharpening.
100
H13
92
S7
85
S5
76
O6
75
A8
72
O1
44
A2
10
D2
10
M2
10
M4

H13, S7, and S5 are easier to grind, while D2, M2, and M4 are more difficult.

2. Tool Steel Selection by Application

The table below gives a starting point for selecting tool steel. It does not replace application testing or heat-treatment confirmation.

Need a faster application-based recommendation?

Use the Tool Steel Material Finder to select an application first and compare suitable Aobo Steel grades with replacement logic.

Open Material Finder
Application / ToolWorking ConditionMain Required PropertyGeneral GradeHigher-Performance Grade
Cutting toolsLight cuts, slow speedsWear resistance with acceptable grindabilityO1, A2M2
Cutting toolsHeavy cuts, fast speedsWear resistance and hot hardnessM2M4, T1, M42
Boring toolsMetal cuttingHot hardness and wear resistanceM2M4
BroachesMetalworkingWear resistance and hot hardnessM2M4
Form cuttersProfile cuttingWear resistance and hot hardnessM2M4
Milling cuttersContinuous cuttingHot hardness and edge wear resistanceM2M4
Thread cuttersThread cuttingWear resistance and hot hardnessM2M4
Woodworking cuttersEdge wear with regrinding requirementWear resistance and grindabilityO1M2
Cold shear bladesLight gauge stockWear resistance with moderate toughnessA2D2
Cold shear bladesHeavy gauge stockImpact resistance and cracking resistanceS5S7
Hot shear bladesHot cuttingHot hardness and toughnessS7, A8H13, H21
Paper knivesEdge wearWear resistanceD2M2, M4
Rotary knivesContinuous cutting wearWear resistanceA8D2
Chipper knivesImpact and edge wearToughness with wear resistanceA2, A8D2, M2
Blanking diesCold work, short runsBalanced wear resistance and machinabilityO1, O6A2
Blanking diesCold work, long runsWear resistance and dimensional stabilityA2D2, M2
Bending diesCold formingToughness and dimensional stabilityO1, O6A2, D2
Coining diesHigh pressure cold workWear resistance and compressive strengthO1A2, D2
Embossing diesCold pressure and surface detailWear resistance and dimensional stabilityA2D2
Cold forming diesGeneral formingWear resistance with stabilityO1A2, D2
Hot forming diesHot workHot hardness and toughnessH13, S7H21
Cold extrusion diesHigh pressure and wearWear resistance with enough toughnessD2M2
Hot extrusion dies for aluminumHeat softening and thermal fatigueHot hardness and toughnessH13H11, H21
Hot extrusion dies for copper and brassHigher hot wear and thermal loadHot hardness and thermal resistanceH13H21
Die casting diesThermal fatigue, heat checking, crackingHot work stabilityH13Premium H13 / ESR H13
Brass die casting diesHigher hot wearHot hardness and heat resistanceH13H21
Hot forging diesHeat, impact, thermal fatigueToughness and hot hardnessH13, S7H21, H43
Hot trimming diesHot impact and edge damageToughness and hot hardnessS7, H13H21
Cold heading toolsImpact, pressure, wearToughness and wear resistanceA2, S7D2, M2
Cold punchesPiercing, trimming, formingWear resistance and toughnessA2, S7D2, M2
Heavy-duty punchesShock-loaded punchingToughness firstS5S7
Draw punchesDrawing pressure and wearWear resistance and toughnessA2, D2M2
Thread rollsSurface pressure and wearWear resistanceD2M2
Forming rollsRolling pressure and wearWear resistance and dimensional stabilityO1, A2D2, D7
Drive rollsWear under contact pressureWear resistanceD2D7
Wire drawing toolsSliding wear and surface pressureWear resistanceD2M4
Plug gaugesWear and dimensional stabilityWear resistance and stabilityA2D2
Master hobsAccuracy and wear resistanceWear resistance and stabilityS7A2, D2
Cutting hobsCutting wear and heatHot hardness and wear resistanceM2T1
Lathe toolsCutting heat and wearHot hardnessM2M42
Planer toolsCutting wearHot hardness and wear resistanceM2M4
Shaper toolsCutting wearHot hardness and wear resistanceM2M4
ReamersCutting accuracy and wearWear resistance and hot hardnessM2M4
TapsThread cutting wearWear resistance and hot hardnessO1M2
DrillsCutting heat and edge wearHot hardness and wear resistanceM2M4
Drill bushingsWear from repeated drillingWear resistanceS5A2
Brake diesBending pressureToughness and wear resistance4140 HTA2
Gripper dies, coldHolding pressure and wearWear resistance and toughnessO1, S7A2, D2
Gripper dies, hotHot gripping and wearHot hardness and toughnessS7, H13H21
Swaging dies, coldImpact and forming pressureToughness and wear resistanceS7D2
Swaging dies, hotHeat and impactHot hardness and toughnessH13, S7H21
Lamination diesWear and edge stabilityWear resistanceA2D2, M2
Plastic moldsMachining, polishing, mold surface qualityMachinability and polishabilityP20, H13420, special mold steels
Impact toolsRepeated shockToughnessS5S7
Battering tools, coldShock and breakageToughnessS5S7
Blacksmith toolsImpact and heatToughnessS5S7
Boiler-shop toolsImpact workToughnessS5S7
Chisels, cold workingImpact and edge chippingToughnessS5S7
Chisels, hot workingHeat and impactToughness and hot hardnessS7M2
Pneumatic toolsRepeated impactToughnessS5S7
Concrete breakersSevere impactToughnessS5S7
Screwdriver bitsTorsion and impactToughnessS5S7
ArborsSupport and wearToughness and dimensional stabilityO1, O6A2, D2
ColletsHolding pressure and wearToughness and wear resistanceO1S5, S7
Chuck jawsHolding pressure and impactToughnessS5S7

3. Selection Notes

Selection NoteMeaning
If the tool wears gradually, start by comparing wear-resistant grades.D2, M2, M4, and related grades are common starting points for abrasive wear.
If the tool chips, cracks, or breaks suddenly, check toughness before increasing hardness.S7, S5, H13, and other tougher grades may be more suitable for shock-loaded tools.
If the tool works under heat, room-temperature hardness is not enough.Hot hardness and resistance to softening become more important.
If the tool requires frequent sharpening, grindability affects maintenance cost.High-wear-resistance grades may be harder to grind.
If the tool is large or complex, heat-treatment distortion must be considered.Air-hardening grades are often used where dimensional stability is important.
If the production run is short, the highest-performance grade may not be economical.Machinability and material cost may be more important for short-run tooling.
If the production run is long, higher wear resistance may reduce total cost.More expensive grades can be justified when they reduce downtime and replacement frequency.

4. Final Technical Check Before Grade Selection

Check ItemConfirm Before Selection
Tool functionCutting, shearing, forming, drawing, extrusion, rolling, impact, molding
Working temperatureRoom temperature, warm work, hot work
Main failure modeWear, chipping, cracking, softening, deformation, distortion
Load levelLight, medium, heavy, shock-loaded
Production volumeShort run, medium run, long run
Section sizeSmall tool, thick section, large die block
Heat treatment targetRequired hardness, toughness, distortion control
Finishing requirementMachining, grinding, polishing, sharpening
Cost targetMaterial cost, machining cost, maintenance cost, cost per part

Tool Steel Supply Support

Aobo Steel supplies common tool steel grades for bulk orders, including D2, A2, S7, H13, H11, O1, and M2.

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