APMT Insert Excels in Hardened Steel H13 Milling

Introduction

Machining hardened H13 die steel (HRC48–51) is always a challenge due to its high hardness and tendency to generate extreme heat during cutting. Excessive cutting temperatures often result in rapid tool wear, edge chipping, or even thermal damage to the carbide substrate.

This case study compares the performance of our APMT1135PDER carbide inserts with a well-known international brand under identical cutting conditions. The results clearly demonstrate the advantages of our advanced AITiN-coated inserts in terms of tool life and wear resistance.

Workpiece & Machining Conditions

Workpiece

Material: H13 die-casting mold steel
Hardness: HRC48–51 (hardened)

Machining Setup

Operation: Dry rough milling (flat surface tool life measured)
Tool holder: BT40
Cutter body: D21-Z2-L60 (overhang)
Insert used: APMT1135PDER

Cutting Parameters

Cutting Speed (Vc)	148 m/min
Feed per Tooth (fz)	0.44 mm/z
Axial Depth of Cut (ap)	0.2 mm
Radial Depth of Cut (ae)	13 mm

Performance Comparison

Insert Brand	Tool Life (per edge)	Wear Condition	Notes
Our Insert APMT1135PDER · AITiN Coating	17 minutes	Minor flank wear Slight edge chipping	Stable cutting performance Good wear resistance
Foreign Brand	11 minutes	Severe flank wear Edge failure observed	Faster tool degradation

Tool life measured under identical cutting parameters during dry rough milling of hardened H13 die steel (HRC48–51).

Key Findings

The advanced AITiN coating provides superior hardness and strong adhesion, significantly improving tool life compared with the foreign brand.
In dry machining of hardened H13 steel, our insert achieved more than 50% longer tool life.
During prolonged cutting, extremely high temperatures may cause plastic deformation of the carbide substrate, potentially leading to thermal damage or tool burning.

Conclusion

The APMT1135PDER carbide insert with advanced AITiN coatingproves to be a strong alternative to international brands for machining hardened H13 die steel. It delivers higher wear resistance and extended tool life, offering manufacturers improved cost efficiency in dry milling operations.

For extremely long machining cycles, effective heat management strategies should still be considered to prevent potential thermal damage.