M2 | 1.3343| S6-5-2 Tool Steel

M2 Tool Steel |1.3343 | S6-5-2 product introduction

M2 tool steel (AISI standard)

M2 tool steel is a molybdenum-based high-speed steel (ASTM standard) with a typical composition of C 0.78-0.90%, W 5.50-6.75%, Mo 4.50-5.50%, Cr 3.80 -4.40%, V 1.75-2.20%. Its red hardness as the core advantage, in the 500 ℃ high temperature still maintains ≥ 60 HRC hardness, at the same time with uniform carbide distribution and good toughness. However, the heat treatment is easy to overheat, requiring strict control of the quenching temperature (1190-1230 ℃) and protective measures. Mainly used in high-load cutting tools (drills, milling cutters, turning tools) and cold work moulds (punching die, extrusion die).

S6-5-2 Tool Steel (GB Standard)

S6-5-2 is a tungsten-molybdenum high-speed steel (corresponding to M2) under the Chinese GB/T 9943 standard, with the same composition as M2. Its wear resistance and impact resistance are better than traditional tungsten high-speed steel, annealed hardness ≤ 255 HB, hardness up to ≥ 64 HRC after quenching at 1210-1230℃ and double tempering at 540-560℃ (salt bath furnace). It is suitable for high impact tools (e.g. gear knives, saw blades) and precision cold heading moulds, and is particularly suitable for thermoplastic forming processes.

1.3343 Tool steel (DIN standard)

1.3343 is a molybdenum-tungsten high-speed steel (grade HS6-5-2C) of the German DIN standard with a composition equivalent to M2/S6-5-2. It is characterised by high hardenability and fine grain organisation, with a hardness of 66 HRC after quenching (oil/gas quenching), but has a significant tendency to decarburise and requires stringent heat treatment protection. Typical applications include complex and valuable tools (broaches, tapping tools), hot rolled drills and EDM moulds, with emphasis on plasticity control in the dynamic recrystallisation temperature range (1150-950°C).

M2 Tool Steel |1.3343 | S6-5-2 Product Types and Options

FCS Factory has a comprehensive line of M2, 1.3343, S6-5-2 tool steel to meet the needs of a wide range of forms and processing options. Whether you need tool steel in standard round, plate, or custom machining specifications, FCS TOOL STEEL FACTORY can meet your needs. The table below shows the size range, surface condition and tolerance details for M2, 1.3343, S6-5-2 tool steel:

Shape	Pocess	Size range	Surface	Tolerance
Flat Bar	Hot Rolled	Thickness: 10-400mm Width: 200-800mm Length: 3000-5800mm	Black; Sandblasted	Thickness :0-+2MM Width:0-+5MM/0-+10MM
	Hot Forged	Thickness: 50-500mm Width: 50-1500mm Length: 3000-5800mm	Black	Thickness:+2-+5MM Width:0-+5MM/0-+10MM
			Turned/Machined/Milled/Bright	Thickness :0-+2MM Width:0-+5MM/0-+10MM
Round Bar	Hot Rolled	Diameter:10-65mm Length:3000-5800mm	Black	0-+2MM
			Turned/Machined	0-+2MM
	Hot Forged	Diameter:70-700mm Length:3000-5800mm	Grinded	0-+5MM/+2-+5MM
			Turned/Machined/Milled/Bright	0-+2MM

M2 Tool Steel |1.3343 | S6-5-2 Customized Options

1.  Customized chemical composition: GB, DIN, ASTM, JIS and other standard grades can be produced. Chemical composition can be customized individually.
2. Customized specifications: round steel (diameter), plate (thickness, width) can be customized production.
3. Specialized packaging for long term storage or extreme transportation conditions: includes spraying black paint all around, wrapping plastic film, spraying anti-rust oil, and shipping in wooden crates.
4. Customized production based on samples or technical agreements.
5. 1.3343,M2,S6-5-2 High-speed Tool Steel Electroslag Remelting (ESR): premium option with higher purity and isotropic properties for critical applications.

M2 Tool Steel |1.3343 | S6-5-2 Chemical composition

Standard/Steel Grade		Chemical Composition(%)
		C	Si	Mn	Cr	Mo	V	W
ASTM	M2	0.78~0.88	0.20~0.45	0.15~0.40	3.75~4.50	4.50~5.50	1.75~2.20	5.50~6.75
DIN/W-Nr.	S6-5-2/1.3343	0.86~0.94	≤0.45	≤0.40	3.80~4.50	4.70~5.20	1.70~2.00	6.00~6.70
JIS	SKH51	0.80~0.90	≤0.40	≤0.40	3.80~4.50	4.50~0.50	1.60~2.20	5.50~6.70
GB	W6Mo5Cr4V2	0.80~0.90	0.20~0.40	0.15~0.40	3.80~4.40	4.50~5.50	1.75~2.20	5.50~6.75

M2 Tool Steel |1.3343 | S6-5-2 Heat Treatment Process

1.Annealing

Purpose: to eliminate internal stresses generated during forging or rolling, reduce hardness, improve cutting performance, and prepare for subsequent processing and heat treatment.
Process parameters:
Heating temperature: 800-850 ℃, holding time 2-4 hours, with the furnace cooling to below 500 ℃, and then air-cooled.
Hardness after annealing: ≤ 248 HBS.

2.Quenching

Purpose: to make the steel to obtain martensitic organization, improve hardness and wear resistance.
Process parameters:
Heating temperature: 1000-1050 ℃ (commonly used 1020-1040 ℃), holding time according to the size of the workpiece to determine, generally 30-60 minutes.
Cooling: oil cooling or air cooling (for small size or simple shape of the workpiece), large workpieces can be graded quenching (in the 260-300 ℃ salt bath cooling for a period of time and then air-cooled), in order to reduce the quenching stress, to prevent deformation and cracking.

3.Tempering

Purpose: to eliminate quenching stress, adjust the hardness and toughness, stable organization and size.
Process parameters:
low-temperature tempering: 150-250 ℃, insulation 2-3 hours, air-cooled, tempered hardness of 58-62HRC, for molds requiring high hardness and wear resistance.
Medium temperature tempering: 300-500 ℃, insulation 2-3 hours, air-cooled, tempered hardness of 50-58HRC, can improve the toughness, suitable for molds subject to impact load.
High-temperature tempering: 500 ℃ or more, insulation 2-3 hours, air-cooled, tempered hardness 45-50HRC, mainly for the need for higher toughness of the occasion.

4.Precautions

Heating process should control the rate of heating to avoid too rapid a rise in temperature leading to workpiece surface oxidation and decarburization. Protective atmosphere heating can be used or placed in the furnace charcoal and other anti-decarburization agent.
When quenching and cooling, choose the appropriate cooling medium and cooling method according to the shape and size of the workpiece to ensure the quenching effect while reducing the risk of deformation and cracking.
Tempering must be sufficient to ensure the elimination of internal stresses to avoid mold failure due to stress release during use. For large molds or workpieces with complex shapes, multiple tempering can be used.

M2 Tool Steel |1.3343 | S6-5-2 Quality Inspection

1.Surface Condition Inspection

FCS factory has a very strict quality inspection team, we will carefully check the surface condition of each piece of tool steel to ensure that the steel surface is free from cracks, folds, knots, oxidized skin, pitting, scratches and other defects.

2.Chemical Composition Testing

To verify whether the content of alloying elements meets the standard requirements and to safeguard the basis of the mechanical properties of the material. We will let the staff use full-spectrum direct reading spectrometer to analyze multiple elements at the same time. Sampling needs to remove the surface oxidation layer, using a block specimen to stimulate the test.

3.Dimension and Tolerance Inspection

FCS factory will use professional measuring tools to inspect the dimensions and tolerances of the steel to ensure compliance with the customer's contract requirements. Corresponding gauges will be selected according to the dimensional accuracy requirements, including tape measure, high-precision vernier calipers (0.02mm), micrometers (0.001mm), and special inspection gauges. Inspection items cover: diameter, thickness, width, length, hole diameter, chamfering dimensions, etc., to ensure that the tolerances and dimensions meet the contract requirements.

4.Hardness test

Our FCS factory will use professional hardness tester to test the hardness of steel to ensure that it meets the customer's contract requirements.

5.Ultrasonic Testing

Ultrasonic Testing Standard (UT Test Standard) is: Sep 1921-84 Class3 D/d,E/e.
FCS factory uses ultrasonic testing equipment to detect macro defects inside the material (such as cracks, shrinkage holes, inclusions, white spots, etc.), and every piece of round steel and plate will be examined by a second flaw detection test before shipment to ensure that the quality is qualified before shipment.

6.Microstructure Inspection

(1) Metallographic Analysis

FCS factory will use metallographic analysis instrument to detect the microstructure state after heat treatment, including carbide distribution, martensite morphology, residual austenite content, etc.

 (2) Grain size rating

FCS factory will use the comparative method to determine the austenite grain size by comparing the microstructure of the specimen with the standard rating chart, to ensure that it meets the customer's requirements.

M2 Tool Steel |1.3343 | S6-5-2 Technical Specifications

Property	Value	Test Method
Density	8.16 g/cm³	ASTM B311
Young's Modulus	217 GPa	ASTM E111
Thermal Conductivity	24 W/m·K (at 20°C)	ASTM E1461
Coefficient of Thermal Expansion	11.5×10⁻⁶/K (20-600°C)	ASTM E831
Maximum Service Temperature	500°C	Internal Testing
Machinability (Annealed)	35-40% (relative to 1% carbon steel)	Internal Testing
Compressive Strength	3100 MPa	ASTM E9
Tensile Strength	1290 MPa	ASTM E8

M2 Tool Steel |1.3343 | S6-5-2 Product Applications

Cutting Tool Manufacturing

M2 tool steel excels in high speed cutting tool applications where heat resistance and edge retention are critical. Our customers use M2 round bar to manufacture drills, end mills, broaches and saw blades that stay sharp even in continuous high-speed operation. The balance of tungsten and molybdenum components provides optimum hot-hardening, enabling cutting tools to operate at speeds up to 30 per cent higher than conventional tool steels.

Industrial moulds and dies

For demanding metal forming operations, M2 steel's excellent compressive strength and wear resistance make it ideal for cold forging dies, precision stamping dies and drawing dies. Our customers report a 40-60% increase in die life when switching to our premium M2 steels, especially in applications where dimensional stability and resistance to pressure distortion are required. Consistent microstructure ensures predictable performance even in complex geometries.

Woodworking Tools

Cabinetmakers and woodworking companies use M2 steels for planer knives, milling cutters and speciality cutting tools where edge retention is critical. The balanced carbide structure provides a clean cutting surface even when grinding engineered and exotic hardwoods. Our precision ground M2 blanks eliminate the need for extensive surface preparation prior to heat treatment, reducing manufacturing time.
Speciality mechanical components

In addition to conventional cutting applications, our M2 steels are increasingly used for highly abrasive mechanical components such as guideways, cam followers and wear plates in speciality machinery. The combination of surface hardness and sufficient core toughness gives excellent service life in applications where conventional steels fail prematurely. Our custom machining service delivers these parts to exact specifications.

M2 Tool Steel |1.3343 | S6-5-2 Comparison Summary

Comparison Dimension	M2 Tool Steel (AISI Standard)	S6-5-2 Tool Steel (GB Standard)	1.3343 Tool Steel (DIN Standard)
Standard System	American AISI M2	Chinese GB/T 9943 S6-5-2	German DIN 1.3343 (HS6-5-2C)
Core Chemical Composition	C 0.78–0.88% W 5.50–6.75% Mo 4.50–5.50% Cr 3.75–4.50% V 1.75–2.20%	Same as M2, C 0.86–0.94% W 6.00–6.70% Mo 4.70–5.20% V 1.70–2.00%	C 0.86–0.94% W 6.00–6.70% Mo 4.70–5.20% Cr 3.80–4.50% V 1.70–2.00%
Hardness (Typical Values)	- Annealed: ≤248 HBS - Quenched & Tempered: ≥63 HRC - Red Hardness (500°C): 65 HRC	- Annealed: ≤248 HBS - Quenched & Tempered: ≥64 HRC (salt bath furnace)	- Annealed: ≤248 HBS - Quenched & Tempered: 64–66 HRC - Red Hardness (550°C): 65 HRC
Heat Treatment Specifications	Quenching: 1190–1230°C (oil cooling) Tempering: 540–570°C × 2–3 times	Quenching: 1210–1230°C (salt bath furnace) Tempering: 540–560°C × 2 times	Quenching: 1190–1230°C (oil/gas quenching) Tempering: 530–560°C × 2 times
Main Application Fields	High-load cutting tools (drills, milling cutters, lathe tools), cold stamping dies	High-impact cutting tools (gear cutters, saw blades), thermoplastic forming molds	Precision valuable cutting tools (broaches, taps), EDM molds
Key Characteristics and Limitations	Advantages: Balanced red hardness and wear resistance Limitations: Prone to overheating, requires strict temperature control	Advantages: Excellent impact resistance, cost-controlled Limitations: Significant decarburization tendency

Customer Success Stories

Skip the middleman link, source factory purchasing, reduce purchasing cost and improve market competitiveness.

Pricing Structure Information

Serving the world, whole cabinet sales, factory wholesale price.

Frequently Asked Questions

Q: What are the main differences between M2 and other high speed tool steels?
A: Due to its balanced tungsten and molybdenum composition, M2 offers the best balance of wear resistance and toughness. Compared to T-series steels (higher tungsten) or M-series variants such as M4 (higher carbon and vanadium), M2 offers excellent red-hardness and wear resistance, while maintaining adequate toughness and good manufacturability for most applications.

Q: What is the appropriate hardness range for M2 in cutting tool applications?
A: For most cutting tool applications, M2 performs best in the 62-65 HRC range. Critical edges may be targeted at the high end of the highest wear resistance target (64-65 HRC), while applications with shock loads or interrupted cuts may be targeted at the low end (62-63 HRC) to improve toughness. Specific application requirements should determine the final hardness target.