Cemented carbide (commonly known as "tungsten steel", with tungsten carbide as the main component) has different grade systems due to variations in national and industrial standards. The core principle is to adjust the particle size of tungsten carbide (WC), content of binder (mainly cobalt, Co), and additive elements (such as TiC, TaC, etc.) to match the hardness, strength, and wear resistance requirements of different processing scenarios. The following is a detailed explanation from three aspects: internationally used grades (ISO standards), Chinese national standards (GB/T), and typical grades and their applications, to facilitate quick matching with application scenarios.

1. Core Classification Logic of Cemented Carbide Grades

The performance of cemented carbide is determined by "tungsten carbide particle size + binder content". The core classification dimensions are as follows:

Performance Dimension Influencing Factors Application Tendency

Hardness/Wear Resistance Finer WC particle size + lower Co content → Higher performance High-speed cutting, precision cutting, wear-resistant parts

Strength/Toughness Coarser WC particle size + higher Co content → Higher performance Rough machining, scenarios with impact loads (e.g., chip breaking, drilling)

Red Hardness Addition of TiC, TaC, etc. → Improved high-temperature stability High-temperature cutting that high-speed steel cannot handle (e.g., stainless steel)

2. Internationally Used Grade System (ISO Standard)

ISO 513 standard classifies cemented carbide into three categories based on "application + performance", covering cutting, wear resistance, forming, and other scenarios, and it is the mainstream reference system worldwide.

2.1 P Category (Identified by Blue): Tungsten-Titanium-Cobalt (WC-TiC-Co) Cemented Carbide

Composition Feature: Contains titanium carbide (TiC), which reduces the affinity between WC and steel and improves the resistance to crater wear.

Core Performance: High red hardness and resistance to high-temperature oxidation, suitable for cutting steel materials (carbon steel, alloy steel, cast steel).

Grade Subdivision: Classified into P01~P50 based on increasing Co content (hardness decreases while toughness increases). The larger the number, the stronger the toughness.

P01/P10: Low Co content (3%~6), fine grain → High hardness, used for high-speed precision turning and milling of steel (e.g., precision turning of bearing steel).

P20/P30: Medium Co content (6%~10), balanced performance → General steel processing (e.g., rough turning and semi-precision turning of ordinary carbon steel).

P40/P50: High Co content (10%~15), coarse grain → High toughness, used for rough machining and interrupted cutting of steel (e.g., rough milling of cast steel blanks).

2.2 K Category (Identified by Red): Tungsten-Cobalt (WC-Co) Cemented Carbide

Composition Feature: Only contains WC + Co (no TiC), with low affinity for non-ferrous metals (e.g., copper, aluminum) and non-metallic materials.

Core Performance: High toughness and impact resistance, suitable for cutting non-ferrous metals, non-metallic materials (copper alloys, aluminum alloys, plastics, wood) and cast iron.

Grade Subdivision: Classified into K01~K50 based on increasing Co content. The larger the number, the stronger the toughness.

K01/K10: Low Co content (3%~6), fine grain → High hardness, used for precision turning of cast iron and precision milling of non-ferrous metals (e.g., precision turning of aluminum alloy wheel hubs).

K20/K30: Medium Co content (6%~10), balanced performance → General cast iron processing and semi-precision turning of non-ferrous metals (e.g., semi-precision turning of copper sleeves).

K40/K50: High Co content (10%~15), coarse grain → High toughness, used for rough machining and interrupted cutting of cast iron (e.g., rough milling of gray cast iron blanks).

2.3 M Category (Identified by Yellow): Tungsten-Titanium-Tantalum (Niobium)-Cobalt (WC-TiC-TaC(NbC)-Co) Cemented Carbide

Composition Feature: Contains TiC + TaC (or NbC), which balances the red hardness of P category and the toughness of K category, with strong thermal shock resistance.

Core Performance: "Universal type", suitable for cutting difficult-to-machine materials (e.g., stainless steel, heat-resistant steel, high-strength alloys) and mixed materials (steel + cast iron).

Grade Subdivision: Classified into M01~M50 based on increasing Co content. The larger the number, the stronger the toughness.

M01/M10: High hardness → High-speed precision cutting of stainless steel (e.g., precision turning of 304 stainless steel pipe fittings).

M20/M30: Balanced performance → Semi-precision turning of stainless steel and processing of heat-resistant steel (e.g., milling of steam turbine blades).

M40/M50: High toughness → Rough machining and interrupted cutting of stainless steel (e.g., rough milling of stainless steel flanges).

3. Chinese National Standard Grades (GB/T 18376.1-2008)

The Chinese standard corresponds to the ISO standard one-to-one, with only different prefix identifiers, facilitating domestic procurement and selection:

Category Chinese Grade Prefix Corresponding ISO Category Core Application Typical Grade Examples

Tungsten-Titanium-Cobalt Type YT P Category Cutting steel materials YT15 (equivalent to P20), YT5 (equivalent to P30)

Tungsten-Cobalt Type YG K Category Cutting non-ferrous metals, cast iron, wear-resistant parts YG6 (equivalent to K10), YG8 (equivalent to K20), YG15 (equivalent to K40)

Tungsten-Titanium-Tantalum-Cobalt Type YW M Category Cutting stainless steel, heat-resistant steel YW1 (equivalent to M10), YW2 (equivalent to M20)

4. Typical Grades and Subdivided Applications (Classified by Scenarios)

4.1 Cutting Processing Scenarios (Most Mainstream Application)

Processed Material Recommended Category Typical Grades (China/ISO) Specific Applications

Carbon Steel/Alloy Steel P Category (YT) YT15/P20 Semi-precision turning, precision turning (e.g., shaft parts made of 45# steel)

YT5/P30 Rough turning, interrupted cutting (e.g., rough machining of alloy steel gear blanks)

Cast Iron (Gray Iron/Ductile Iron) K Category (YG) YG6/K10 Precision turning, precision milling (e.g., precision turning of ductile iron crankshafts)

YG8/K20 Semi-precision turning, general processing (e.g., milling of gray iron boxes)

YG15/K40 Rough machining, impact cutting (e.g., rough milling of cast iron blanks)

Stainless Steel/Heat-Resistant Steel M Category (YW) YW1/M10 Precision turning, high-speed cutting (e.g., 316 stainless steel pipe fittings)

YW2/M20 Semi-precision turning, milling (e.g., processing of heat-resistant steel bolts)

Aluminum Alloy/Copper Alloy K Category (YG) YG6X/K05 Precision turning, high-finish processing (e.g., aluminum alloy casings)

YG8/K20 Semi-precision turning, general processing (e.g., turning of copper sleeves)

4.2 Wear-Resistant Part Scenarios (Non-Cutting Applications)

Mainly use tungsten-cobalt type (YG), which relies on high wear resistance, and is commonly used in machinery, mining, and electronics industries:

YG6/YG6X: Fine grain, high hardness → Used for wire drawing dies, cold stamping dies, nozzles (e.g., wire drawing dies for electric wires, printer nozzles).

YG8: Balanced wear resistance + strength → Used for bearing raceways, seal rings (e.g., cemented carbide rings for mechanical seals).

YG15: High toughness → Used for mining rock drill bits, crusher hammers (e.g., drill bits for granite mining).

4.3 Special Application Scenarios

Ultra-Fine Grain Cemented Carbide (e.g., YG03X): WC particle size ≤ 0.5μm, hardness ≥ 93HRA → Used for precision cutting tools, micro-drills (e.g., drilling of PCB circuit boards).

Non-Magnetic Cemented Carbide (e.g., YG11C): Contains Ni binder, non-magnetic → Used for medical equipment, parts of magnetic separation equipment (e.g., guide parts of MRI equipment).

5. Core Mnemonic for Grade Selection

Check the material: Use P (YT) for steel, K (YG) for cast iron/non-ferrous metals, and M (YW) for stainless steel.

Check the processing method: Choose low-cobalt grades (e.g., YT15, YG6) for precision machining, and high-cobalt grades (e.g., YT5, YG15) for rough machining.

Check the impact: Choose high-toughness grades (e.g., P50, K40) for interrupted cutting and large feed rates.

Through the above system, you can quickly match the corresponding cemented carbide grade based on the processed material and working conditions, avoiding problems such as "tool chipping or low processing efficiency due to incorrect grade selection".