end mill end mill end mill

End Mill for Hardened Steel 4 Flute Flat End Mill

SAMHO Diamond-Coated 4-Flute Flat End Mill for High-Hardness & Heat-Treated Steel — The Ultimate Tool for High-Precision CNC Machining

Stop letting the machining of high-hardness materials and heat-treated steels increase your costs. The SAMHO High-Hardness Steel Series is precision engineered for professional CNC operations and specifically designed for high-precision machining of hardened steels and heat-treated alloys.

Leveraging advanced high-adhesion coating technology, this 4-flute flat end mill delivers long-lasting durability and consistent performance in real-world applications, significantly extending tool life.

Applicable Materials: Optimized for high-hardness steels, heat-treated steels, and other highly wear-resistant materials.

Ultimate Durability: Made with a high-strength, fine-grain cemented carbide substrate. Combined with precision grinding and a high-adhesion coating, it ensures sharp cutting edges and chemical inertness, ideal for continuous high-load machining.

High-Efficiency Machining: The 4-flute design optimizes chip removal and cutting force distribution. It reduces cutting heat while improving machining efficiency and surface finish.

In the field of machining high-hardness and heat-treated steels, tool performance requirements are exceptionally stringent. Precision and durability are both critical. SAMHO 4-flute flat end mills (D1–D12 mm) are engineered specifically for these demanding applications. They are optimized for professional CNC operations, delivering increased machining efficiency while maintaining excellent surface finish and dimensional accuracy. These end mills are the ideal choice for precision machining of high-hardness and heat-treated steels.


Advanced Technical Features

Specialized High-Adhesion Coating for Ultra-Long Tool Life
Our proprietary coating technology gives the tool exceptional hardness and chemical resistance:

  • Wear Resistance: Cutting edges stay sharp even during long, continuous machining of heat-treated steels.
  • Micro-Chipping Prevention: The coating maintains a strong bond with the carbide substrate in high-speed cutting, extending tool life.

4-Flute Geometry Specifically Designed for High-Hardness Steels
The precision 4-flute design optimizes cutting force distribution and chip evacuation:

  • High-Efficiency Cutting: Reduces cutting heat and minimizes tool wear.
  • Stable Machining: Ensures dimensional accuracy and high-quality surface finish when machining heat-treated steels.

Ultra-Precision Carbide Substrate and High-Accuracy Grinding
High-strength, fine-grain carbide combined with precise grinding ensures consistent machining performance:

  • Dimensional Tolerance Control: Maintained within ±0.01 mm for reliable batch production.
  • Fracture Resistance: Significantly increases tool durability, ideal for high-hardness steels and abrasive materials.

4-Flute “Cool-Cutting” Design
The sharp 4-flute geometry reduces cutting heat and improves chip evacuation:

  • Maximized Chip Evacuation: Quickly removes heat and chips from the cutting zone.
  • Reduced Cutting Load: Minimizes heat buildup, preventing thermal cracking in brittle steel.

Target Applications & Industries

This series of 4 flute square end mills is designed for precision CNC operations and is widely applicable for:

  • Precision machining of high-hardness and heat-treated steels
  • Processing highly wear-resistant and brittle materials
  • Creating high-precision contours and complex geometries

Why Choose SAMHO as Your Wholesale Partner?

Superior Performance: Precision engineered for high-hardness and heat-treated steels. Delivers reliable high-precision machining and long-lasting durability.

High-Efficiency Machining: The 4-flute design optimizes chip evacuation, reduces cutting heat, and increases production efficiency.

Reliable Quality: Made with a high-strength, fine-grain carbide substrate. Dimensional tolerances are strictly controlled to ensure consistency in batch production.

Technical Customization: Supports OEM and ODM services to meet specific client requirements.

Global Supply: Provides stable delivery to support smooth operations for international B2B businesses.

Recommended Materials for Machining (Highly Recommended: ⭐️ | Recommended: ⭕️ | Suggested: )

Category Work Material Grade
DIE STEEL Carbon steels (S45C/S55C)
Alloy steels (SK/SCM/SUS)
Prehardened steels (NAK/HPM)
Hardened steels (~55/~60/~70HRC) ⭐️
SPECIAL MATERIAL Aluminum alloys
Graphite
Copper
Plastics
Carbon fiber
Titanium alloys
Heat resistant alloys
Cemented carbide
Hard brittle (non-metallic) material

4 flute flat end mill

Total 24 models

Model Number Outside Diameter Length Of Cut Effective Length Shank Taper Angle Overall Length Number Of Flutes Shank Diameter In Stock
SHHS4-0100300 1 3 12° 50 4 4
SHHS4-0150400 1.5 4 12° 50 4 4
SHHS4-0200500 2 5 12° 50 4 4
SHHS4-0250600 2.5 6 12° 50 4 4
SHHS4-0300800-3 3 8 50 4 3
SHHS4-0300800-4 3 8 12° 50 4 4
SHHS4-0300800-6 3 8 12° 60 4 6
SHHS4-0401000-4 4 10 50 4 4
SHHS4-0401000-6 4 10 12° 60 4 6
SHHS4-0401000-75 4 10 12° 75 4 4
SHHS4-0501300 5 13 12° 60 4 6
SHHS4-0601500 6 15 60 4 6
SHHS4-0601500-75 6 15 75 4 6
SHHS4-0601500-100 6 15 100 4 6
SHHS4-0802000 8 20 60 4 8
SHHS4-0802000-75 8 20 75 4 8
SHHS4-0802000-100 8 20 100 4 8
SHHS4-0802000-150 8 20 150 4 8
SHHS4-1002500 10 25 75 4 10
SHHS4-1002500-100 10 25 100 4 10
SHHS4-1002500-150 10 25 150 4 10
SHHS4-1203000 12 30 75 4 12
SHHS4-1203000-100 12 30 100 4 12
SHHS4-1203000-150 12 30 150 4 12

Contour Milling Parameters

Work Material HRC48-55 Hardened steels HRC56-62 Hardened steels HRC63-70 Hardened steels
Diameter (min-1) Speed (mm/min) Feed (min-1) Speed (mm/min) Feed (min-1) Speed (mm/min) Feed
1 22000 600 20000 500 15000 400
1.5 18000 700 16000 600 12000 400
2 15000 900 12000 600 10000 500
2.5 13000 900 10000 600 9000 500
3 11000 1000 8000 700 7000 600
4 8500 1200 7500 800 6000 600
5 7500 1500 6000 1200 5000 600
6 6500 1800 5500 1000 4500 600
8 5000 2000 4000 1200 3500 700
10 4000 2000 3200 1500 2500 800
12 3500 2000 2500 1500 2200 800

Milling Amount for Side Milling(mm)

Work Material \ Length of Cut 2.5D (Length of Cut=Diameter*2.5) 4D (Length of Cut=Diameter*4)
45HRC以下Below 45HRC ae​=0.07Dap​=2D ae​=0.07Dap​=2D
45HRC以上Above 45HRC ae​=0.03Dap​=1.5D ae​=0.03Dap​=1.5D

D: Diameter (mm)

ap:AxialDepth (mm)

ae: Radial Depth (mm)

Note:

*Decrease both spindle speed and feed rate proportionally when the milling parameters exceed the machine’s maximum spindle speed;

*Recommend oil coolant for Stainless Steels and Heat Resistance Alloys;

*Recommend using a non-contact measuring device to avoid damaging the precisiontip point;

*Decrease both spindle speed and feed rate proportionally in case of chattering;

*When the material hardness is greater than HRC58 degrees, it is recommended to use air blow cooling for roughing andoil mistor air blow cooling for finishing.

Download 2: End Mill for Hardened Steel 4 Flute Flat End Mill File

Related Product

Related Post

Get Your Custom Milling Tool Guide

Fill out the form below to receive SAMHO’s complete product catalog.