Carbide End Mills for Steel | GM/PM/HM Series up to 68 HRC

Choose the Right Series for Your Steel Hardness

Series	Hardness Range	Coating	Max Operating Temp	Available Geometries	Best For
GM Series	≤ 38 HRC	`TiSiN`	~650°C	Flat, Ball Nose, Corner Radius, Roughing, Long Reach	Carbon steel, alloy steel, general machining, high MRR roughing
PM Series	≤ 55 HRC	`AlTiCrN Composite`	~800°C	Flat (4F/6F), Ball Nose, Corner Radius, Long Reach	Pre-hardened steel, stainless, interrupted cuts, tough alloys
HM Series	55 – 68 HRC	`Balzers DR`	~900°C	Flat, Ball Nose, Corner Radius	Hardened tool steel, mold finishing, high-precision contouring

*All series feature h6 shank tolerance, ≤0.003mm cutting edge tolerance, and 5-axis precision grinding. Coating performance validated under standard flood coolant or high-pressure TSC conditions.

Explore Our Steel Milling Lineup

Select your hardness tier, then choose the geometry that matches your operation. Click any card to view full specifications, tolerances, and starting parameters.

Series：

ALL GM Series PM Series HM Series

Profile：

ALL Flat Ball Nose Corner Radius Roughing

PM Series, Carbide Corner Radius End Mill

For high-precision radius shoulder & profile finishing of hardened steels <55HRC. 45° helix with AlTiCrN composite coating. Ideal for mold finishin···

View Specs

💡 Engineering Note: HM series focuses on standard lengths to maximize core rigidity for hard milling. For deep hardened steel cavities, we recommend step-down strategies or custom long-reach HM tools upon request.

How to Select the Right Carbide End Mill for Steel

Don’t guess. Follow this 4-step matching logic used by CNC programmers and tooling engineers:

Match Hardness First: ≤38 HRC → GM. ≤55 HRC → PM. 55-68 HRC → HM. Running a GM tool on HRC 48 steel will cause rapid thermal softening & flank wear.
Match Coating to Heat Profile: TiSiN handles moderate heat in carbon/alloy steel. AlTiCrN composite resists oxidation & adhesion in stainless/interrupted cuts. Balzers DR provides extreme thermal barrier & edge retention for hard milling.
Match Geometry to Operation: Flat 4F/6F for slotting/facing. Ball Nose 2F for 3D contouring. Corner Radius 4F for shoulder strength. Roughing 4F for high MRR. Long Reach for deep cavities.
Verify Setup Discipline: Keep tool runout ≤0.003mm, use hydraulic/shrink-fit holders for HM series, and validate coolant alignment. Hard milling forgives nothing.

For detailed starting parameters, toolpath strategies, and troubleshooting signals, see our technical guides: Boost Steel Machining Efficiency | Best End Mill for Hardened Steel | Coating Comparison: TiSiN vs AlTiCrN vs Balzers DR

Precision Manufacturing & Quality Control

Every Amony steel end mill is built to deliver repeatable performance, not just catalog specs:

Substrate: Premium ultra-fine grain carbide (0.4-0.6μm) optimized for each hardness tier
Coating: PVD applied in certified partners’ facilities. Uniform thickness, no edge buildup
Tolerances: Shank h6 | Cutting diameter ±0.005mm (GM/PM) / ±0.003mm (HM) | Corner radius ±0.01mm
Runout Control: ≤0.003mm at 2×D. Verified on laser tool setters before shipment
Edge Preparation: Micro-hone optimized per series. GM: sharp for MRR. PM: balanced for toughness. HM: precision-honed for hard milling finish
100% Inspection: Every batch tested for geometry, coating adhesion, and dimensional accuracy. Certificate of conformity available upon request

Frequently Asked Questions

Can I use GM series tools for HRC 45 steel?

Not recommended. GM series substrates and TiSiN coatings are optimized for ≤38 HRC. For HRC 40-55, switch to PM series with AlTiCrN composite coating to prevent thermal softening and premature flank wear.

What’s the real difference between TiSiN, AlTiCrN, and Balzers DR?

TiSiN (~650°C) excels in carbon/alloy steel with high oxidation resistance. AlTiCrN Composite (~800°C) adds toughness & anti-adhesion for stainless, interrupted cuts, and pre-hardened steel. Balzers DR (~900°C) is a premium hard-milling coating with extreme thermal barrier & edge retention for 55-68 HRC tool steels.

Do you offer long-reach options for hardened steel (HM series)?

Standard HM tools focus on maximum core rigidity for hard milling. For deep cavities in 55-68 HRC steel, we recommend step-down machining strategies or custom long-reach HM tools. Contact our engineering team for application-specific designs.

What holder type do you recommend for these end mills?

For GM/PM: high-precision collet (ER-GB) or hydraulic holders. For HM series: hydraulic or shrink-fit holders are strongly recommended to maintain ≤0.003mm TIR. Runout is the #1 cause of hard milling failure.