O1 Tool Steel | 1.2510 |100MnCrW4

O1 Tool Steel | 1.2510 |100MnCrW4 Product Introduction

O1 tool steel (American ASTM Standard)

O1 is a high carbon, low alloy, oil hardened tool steel (UNS T31501) under the American ASTM standard, with core compositions of carbon (0.85-1.00%), manganese (1.00-1.40%), chromium (0.40-0.60%) and traces of tungsten (0.40-0.60%) and vanadium (≤0.30%). Its properties centre on high dimensional stability and oil hardenability, with a heat-treated hardness of 57-62 HRC, but with moderate wear resistance (industry rating 4/6) and no corrosion resistance due to low chromium content.

1.2510 Tool Steel (German W-Nr/DIN Standard)

1.2510 is a German W-Nr/DIN numbered cold work tool steel classified as a medium alloy oil hardened steel, the same material as 100MnCrW4. Its composition is based on high carbon (0.90-1.05%), manganese (1.00-1.20%), with the addition of chromium (0.50-0.70%), tungsten (0.50-0.70%) to enhance wear resistance, hardness after quenching up to 60 -65 HRC; properties include low heat distortion (~1% volume change) and high compressive strength (740 N/mm²) with a density of 7.85 g/cm³.

100MnCrW4 tool steel (German DIN material number)

100MnCrW4 is the equivalent grade of 1.2510 and follows the DIN standard, labelled as a high carbon tungsten-chromium-manganese alloy steel. Its composition is identical to that of 1.2510, but highlights the synergistic strengthening properties of manganese and tungsten: the manganese improves hardenability and the tungsten refines the carbide distribution, resulting in a hardness of 62-65 HRC and a thermal conductivity (30 W/m-K) slightly higher than that of O1 (33 W/m-K).

O1 Tool Steel | 1.2510 |100MnCrW4 Product Types and Options

The table below shows the size range, surface condition and tolerance details for O1,1.2510,100MnCrW4 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

O1 Tool Steel | 1.2510 |100MnCrW4 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. O1,1.2510,100MnCrW4 Cold Work Tool Steel Electroslag Remelting (ESR): premium option with higher purity and isotropic properties for critical applications.

O1 Tool Steel | 1.2510 |100MnCrW4 Chemical Composition

Standard/Steel Grade		Chemical Composition(%)
		C	Si	Mn	Cr	V	W
ASTM	O1	0.85~1.00	0.10~0.50	1.00~1.40	0.40~0.60	≤0.30	0.40~0.60
DIN/W-Nr.	100MnCrW4/1.2510	0.90~1.05	0.15~0.35	1.00~1.20	0.50~0.70	0.05~0.15	0.50~0.70
JIS	SKS3	0.90~1.00	≤0.35	0.90~1.20	0.50~1.00	-	0.50~1.00

O1 Tool Steel | 1.2510 |100MnCrW4 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: ≤ 230 HBS.

2.Quenching

Purpose: to make the tool 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.

O1 Tool Steel | 1.2510 |100MnCrW4 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.

O1 Tool Steel | 1.2510 |100MnCrW4 Technical Specifications

Parameters	O1 (AISI)	1.2510 (DIN)	100MnCrW4 (ISO)
Hardness Range	58-62 HRC	58-62 HRC	58-62 HRC
Annealed Hardness	≤230 HB	≤230 HB	≤230 HB
Density	7.81 g/cm³	7.81 g/cm³	7.81 g/cm³
Elastic Modulus	190-210 GPa	190-210 GPa	190-210 GPa
Coefficient of Thermal Expansion	11.5 × 10⁻⁶/K (20-100°C)	11.5 × 10⁻⁶/K (20-100°C)	11.5 × 10⁻⁶/K (20-100°C)
Thermal Conductivity	34.5 W/(m·K)	34.5 W/(m·K)	34.5 W/(m·K)
Quenching Temperature	780-820°C	780-820°C	780-820°C
Tempering Temperature	160-200°C	160-200°C	160-200°C

O1 Tool Steel | 1.2510 |100MnCrW4 Product Applications

Precision Stamping Dies

O1/1.2510/100MnCrW4 tool steel is the ideal material for precision stamping dies due to its excellent wear resistance and dimensional stability. In applications for automotive component manufacturers, precision stamping dies made from our tool steel can handle medium carbon steel plates up to 3mm thick and complete more than one million stamping operations without replacement or reconditioning. They are particularly suitable for stamping processes requiring high surface quality and dimensional accuracy, such as the production of electronic connectors and precision sheet metal parts.

Plastic mould inserts

In plastic injection moulds, O1 tool steel is often used for mould inserts that are subjected to high wear. A supplier of electronic housings uses our tool steel for mould cavity inserts and maintains a mould life of more than 1 million cycles with a dimensional accuracy of ±0.02 mm, even under conditions of reinforced plastic injection moulding with 30% glass fibre. This application is particularly suitable for consumer electronics moulds that require high surface finish and long mould life.

Precision Gauge Manufacturing

1.2510 tool steel excels in gauge manufacturing. A manufacturer of precision measuring instruments uses our tool steel to produce the measuring faces of high-precision calipers and micrometers, which show excellent wear resistance and dimensional stability after heat treatment to 60 HRC. These gauges maintain ±0.001mm measurement accuracy even after prolonged use, meeting the stringent requirements of the aerospace and precision machinery industries.

Woodworking tool applications

In the woodworking industry, 100MnCrW4 tool steel is widely used for planers, milling cutters and carving tools. Woodworking tools made from our tool steel by a high-end furniture manufacturer maintain sharp cutting edges in hardwood machining, significantly reducing downtime due to regrinding and improving productivity and quality. These tools are particularly suited to solid wood furniture and musical instruments that require fine surface finishes.

O1 Tool Steel | 1.2510 |100MnCrW4 Competitive Advantage Comparison

Performance Indicators	O1/1.2510/100MnCrW4 Tool Steel from FCS Factory	Ordinary Similar Tool Steel
Hardness Consistency	Small difference	Large difference
Dimensional Stability	Low heat treatment deformation rate	High heat treatment deformation rate
Internal Defects	Ultrasonic flaw detection pass rate >99.5%	Ultrasonic flaw detection pass rate 96-98%
Machinability	Cutting speed can be increased by 15-20%	Standard cutting parameters
Technical Support	24-hour response, providing complete heat treatment recommendations	Basic technical support, response time 48-72 hours
Customization Service	Custom services available according to customer needs	Only standard sizes available

O1 Tool Steel | 1.2510 |100MnCrW4 Customer Success Stories

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O1 Tool Steel | 1.2510 |100MnCrW4 Pricing Structure Information

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O1 Tool Steel | 1.2510 |100MnCrW4 Frequently Asked Questions

Q:What is the difference between O1, 1.2510 and 100MnCrW4 tool steel?
A: These three standards describe basically the same kind of tool steel, just according to the naming system of different countries or organisations named. O1 tool steel is the American AISI standard, 1.2510 and 100MnCrW4 is the German DIN standard. Their chemical composition and performance characteristics are basically the same, the main difference is that the standards of the composition of the allowable range of subtle differences. 2.

Q: What are the advantages over D2 or A2 tool steels?
A: Compared to D2 tool steel, O1 tool steel offers better toughness and lower risk of deformation, but slightly lower wear resistance. Compared to A2, O1 offers better grindability and a higher surface finish that is easier to achieve, but is slightly less resistant to softening at high temperatures.The main advantages of O1 are simplicity of heat treatment, low distortion, good machinability and cost-effectiveness.

Q:Can you provide customised sizes?
A:Yes, as a specialised tool steel supplier, we offer flexible delivery options to a wide range of customers. In addition to wholesale service for standard sizes, we also accept customised size requests. For special projects, we offer a cutting service that allows us to supply material to the exact size required by the customer, reducing material waste and processing costs.

Q:How do international customers handle imports?
A:First of all, FCS TOOL STEEL has its own tool steel manufacturing plant. In addition, FCS Factory has extensive experience in international trade and can provide comprehensive import and export services to international customers. Our international trade team can assist in the preparation of all necessary import and export documentation. We are familiar with customs requirements in all major markets and can help our clients through the import process. At the same time, we work with a number of international logistics companies to provide competitive shipping solutions.