Korloy T9000 Series: Next-Generation Turning Grades for 2026

Korloy, one of South Korea’s leading carbide cutting tool manufacturers, introduced the T9000 series as its flagship turning grade family targeting the ISO P15-P35 steel-turning segment. The T9000 series builds on Korloy’s established reputation for cost-effective, production-proven grades while incorporating advanced coating and substrate technologies designed to compete directly with premium offerings from Sandvik, Kennametal, and Mitsubishi. This article provides a detailed technical analysis of the T9000 series grades, their capabilities, and where they fit in the competitive landscape.

T9000 Series Overview and Technology Platform

The T9000 series encompasses three primary grades: T9015, T9025, and T9035, each covering a different segment of the steel-turning application range. All three grades share a common coating platform based on Korloy’s proprietary nano-structured CVD coating process, which deposits alternating layers of TiCN and Al2O3 with a total thickness optimized for each specific grade’s target application.

The T9015 targets ISO P10-P20 for high-speed finishing and semi-finishing of carbon and low-alloy steels. The T9025 covers ISO P15-P30 as the general-purpose workhorse grade. The T9035 addresses ISO P25-P40 for heavy roughing and interrupted cutting operations. This three-grade structure mirrors the approach used by Sandvik Coromant with its GC4215/GC4225/GC4235 family, allowing shops to standardize on the T9000 platform while selecting the appropriate grade for each operation.

T9015: High-Speed Finishing Grade

T9015 uses a fine-grain carbide substrate with a hardness of approximately 1600 HV and transverse rupture strength of approximately 2200 MPa. The coating stack consists of a TiCN inner layer approximately 3 micrometers thick, an Al2O3 middle layer approximately 2 micrometers thick, and a TiN outer layer approximately 0.5 micrometers thick for visual wear detection. Total coating thickness is approximately 5.5 micrometers.

The fine-grain substrate maintains a sharp cutting edge even after extended cutting time, which is essential for achieving fine surface finishes in semi-finishing and finishing operations. T9015 achieves cutting speeds of 280 to 400 m/min on normalized 1045 steel at feeds of 0.12 to 0.25 mm/rev, producing surface finishes of Ra 0.4 to 1.2 micrometers depending on nose radius and feed rate.

T9025: General-Purpose Grade

T9025 is positioned as the first-choice grade for most steel-turning operations. It uses a medium-grain substrate with hardness of approximately 1520 HV and transverse rupture strength of approximately 2450 MPa. The coating is a multi-layer TiCN/Al2O3/TiN stack at approximately 8 micrometers total thickness, providing a thicker protective barrier than T9015 for enhanced wear resistance in medium-to-heavy cutting conditions.

In production testing on SCM440 (4140 equivalent) at 28 to 32 HRC, T9025 achieved tool life of approximately 25 minutes at 220 m/min, 0.25 mm/rev feed, and 2.5 mm depth of cut. This performance is within 10 to 15 percent of Sandvik GC4225 under identical conditions, while the T9025 inserts are typically priced 25 to 30 percent lower.

T9035: Heavy-Duty Roughing Grade

T9035 uses a coarse-grain substrate with hardness of approximately 1460 HV and transverse rupture strength of approximately 2700 MPa. The high TRS provides the impact resistance needed for interrupted cuts and heavy roughing operations. The coating is thinner than T9025 at approximately 6.5 micrometers, with a reduced Al2O3 layer to improve coating adhesion under high mechanical load.

T9035 is designed for depths of cut up to 6 mm and feeds up to 0.50 mm/rev on carbon and alloy steels. Its primary applications include roughing of forgings with scale, turning of castings with hard surfaces, and interrupted cuts on splined shafts and gears.

Chipformer Geometries

Korloy provides the T9000 series with five chipformer options covering the full range of turning operations. The GF chipformer handles finishing at feeds of 0.08 to 0.20 mm/rev with a 10 to 12 micrometer hone on the cutting edge. The GM chipformer covers semi-finishing at feeds of 0.15 to 0.30 mm/rev with a 15 to 18 micrometer hone. The MM chipformer targets medium turning at feeds of 0.20 to 0.40 mm/rev. The GR chipformer handles roughing at feeds of 0.30 to 0.50 mm/rev with a reinforced edge preparation. The HR chipformer is designed for heavy roughing at feeds of 0.35 to 0.60 mm/rev with the most robust edge geometry in the lineup.

Competitive Comparison

The data shows that T9025 delivers approximately 89 percent of GC4225’s tool life at roughly 70 percent of the cost, resulting in a cost-per-minute-of-cutting-time advantage of approximately 20 percent in favor of T9025. For high-volume operations where insert consumption is a major cost driver, this difference is economically significant.

Recommended Applications by Industry

For automotive component manufacturing, T9025 with the MM chipformer is recommended for turning shafts, bushings, and flanges from 1045 or 4140 steel. The typical parameters are 220 to 280 m/min, 0.20 to 0.30 mm/rev, and 1.5 to 3.0 mm depth of cut.

For oil and gas component machining such as valve bodies and fittings from 4130 or 8630 steel, T9025 or T9035 with the GR chipformer is recommended at 160 to 220 m/min, 0.25 to 0.40 mm/rev, and 2.0 to 4.0 mm depth of cut.

For hydraulic cylinder production using honed tubing of 1045 or STKM material, T9015 with the GF chipformer is the preferred choice for finish boring at 300 to 380 m/min, 0.10 to 0.18 mm/rev, and 0.3 to 0.8 mm depth of cut, achieving Ra 0.4 to 0.8 micrometers.

Implementation Recommendations

When adopting T9000 series grades, start with parameters 10 percent below the recommended values and increase incrementally after verifying stable cutting conditions. The T9000 grades perform best with flood coolant at pressures above 15 bar. For dry machining, reduce cutting speed by 20 to 25 percent and use air blast to clear chips from the cutting zone. Always ensure that the insert seating surface is clean before indexing, as the CVD coating’s thicker layers are more sensitive to seating irregularities than PVD coatings.

Conclusion

Korloy’s T9000 series offers a compelling value proposition for production turning operations. The three-grade structure provides coverage from high-speed finishing to heavy roughing, and the nano-structured CVD coatings deliver performance within 10 to 15 percent of premium Western brands at significantly lower cost. For shops seeking to reduce insert expenditure without sacrificing productivity, the T9000 series warrants serious evaluation as a primary steel-turning grade platform.