Corten Steel Plate
Atmospheric corrosion resistant plate that builds its own protective rust instead of paint
Specifications
Alloy Steel Sheet
Cobalt Bearing Molybdenum High Speed Tool Steel
Molybdenum cobalt high speed tool steel for drills reamers broaches and gear cutters
1.3243 is a molybdenum based high speed tool steel with a cobalt addition, also listed as M35, HS6-5-2-5, SKH55 and W6Mo5Cr4V2Co5. Tool grinders and cutting tool makers choose it over plain M2 because the 5% cobalt content carries hardness and cutting performance further at the temperatures a working edge actually reaches. It is the grade to reach for when tools made from a lower alloy high speed steel are softening or losing their edge before the batch is finished, since the alloy holds hardness up to 64-66 HRC after heat treatment. Material is supplied to 0-1000mm in the annealed or quenched and tempered condition and in raw, milled or ground surface.
- Product Name — High speed steel
- Grade — M35 1.3243 HS6-5-2-5 SKH55 W6Mo5Cr4V2Co5
- Type — Molybdenum mix cobalt based high speed tool steel
- Hardness After Heat Treatment — 64-66 HRC
- Cobalt Content — 5%
Why It Is Specified
Key Benefits of 1.3243 high speed steel
Cobalt Content Above Standard M2
The ability to carry 5% cobalt is what separates this grade from HSS M2. It is the reason the tool keeps cutting when heat builds at the edge.
Hardness To 64-66 HRC After Heat Treatment
Post heat treatment hardness reaches 64-66 HRC, which is what a drill or reamer needs to hold a clean edge geometry through a production run.
Red Hardness Under Working Heat
High heat resistance and red hardness mean the tool does not lose its temper as cutting speed and feed push the edge temperature up.
Fine Evenly Distributed Carbides
The carbides in this conventional steel are small and evenly distributed, which supports a keen ground edge and consistent grinding behaviour.
Tensile Strength and Wear Resistance Together
High tensile strength and high abrasion resistance sit in the same grade, so the tool resists both edge wear and breakage in interrupted cuts.
Supplied Raw Milled or Ground
Surface is available as raw material, milled or ground, so a tool shop can buy stock ready for grinding instead of spending machine time squaring it up.
Problems It Solves
What This Material Removes From Your Process
Tools Softening Before the Batch Is Finished
A lower alloy high speed steel loses hardness as the edge heats up. The cobalt bearing grade holds hardness and red hardness so the tool finishes the run.
Edge Wear Forcing Early Regrinds
High abrasion resistance and hardness up to 64-66 HRC extend the interval between regrinds, which means fewer tool changes in the machine.
Inconsistent Grinding From Coarse Carbides
Carbides in this grade are small and evenly distributed, so ground edges come out consistent rather than chipping along a coarse structure.
Paying Premium Prices for Cobalt Grades
This grade is described as effective and economically priced, which is why it is one of the most commonly used high speed steel grades worldwide.
Drawings Naming Four Different Designations
1.3243 M35 HS6-5-2-5 SKH55 and W6Mo5Cr4V2Co5 are the same material. One enquiry covers whichever name your print uses.
Application Scenarios
Where It Is Used
Twist Drills and Drilling Tools
Drill blanks where the point runs hot in deep holes and a plain high speed steel would soften first.
Reamers and Finishing Tools
Reamers that must hold a size and a fine edge across a long production batch.
Gear Cutters and Hobs
Gear cutting tools where many teeth must stay identical and a lost edge on one flank spoils the part.
Broaches and Broaching Tools
Broaches carrying heavy chip loads on every tooth in a single pass through the work.
Die Steel and Tool Inserts
Die steel applications and inserts calling for high hardness with abrasion and heat resistance.
General Cutting Tool Manufacture
Manufacturing various cutting tools in a tool room where one economical grade needs to cover most of the range.
Who It Is For
Buyers Who Specify This Product
- Cutting tool manufacturers buying HSS stock for drills reamers and hobs
- Tool room supervisors sourcing blanks that will be ground to a finished profile
- Die and mould shops buying die steel for inserts working under heat and abrasion
- Maintenance workshops making replacement broaches and form tools in house
- Tool steel stockists holding M35 and 1.3243 for regional tool grinders
- Purchasing engineers matching a drawing that names SKH55 HS6-5-2-5 or W6Mo5Cr4V2Co5
Technical Data
Specifications and Technical Features
Values below come from the product data published by Shandong Tianyu Metal Products. Confirm the exact grade and size against your order.
| Product Name | High speed steel |
|---|---|
| Grade | M35 1.3243 HS6-5-2-5 SKH55 W6Mo5Cr4V2Co5 |
| Type | Molybdenum mix cobalt based high speed tool steel |
| Hardness After Heat Treatment | 64-66 HRC |
| Cobalt Content | 5% |
| Thickness | 0-1000mm |
| Size | Customized Size |
| Technique | Annealed quenched and tempered |
| Surface | Raw material milling grinding |
| Chemical Composition | C 0.82-0.95 W 5.50-6.50 Cr 3.80-4.50 Mo 4.75-5.25 V 1.75-2.15 Si 0.20-0.45 Mn 0.15-0.40 P 0.030 S 0.030 |
| Application | Manufacturing various cutting tools |
| Processing Service | Bending welding decoiling cutting punching |
| Certificate | Mill Test Certificate |
| Place of Origin | China |
Technical Features
- Molybdenum based cobalt alloyed high speed tool steel
- Grades 1.3243 M35 HS6-5-2-5 SKH55 and W6Mo5Cr4V2Co5
- Cobalt content giving the grade its advantage over HSS M2 at 5%
- Hardness up to 64-66 HRC after heat treatment
- Thickness 0-1000mm with customized size
- Delivery condition annealed or quenched and tempered
- Surface raw material milled or ground
- Processing service bending welding decoiling cutting and punching
Materials
- Cobalt bearing molybdenum high speed tool steel 1.3243 also listed as M35
- Alloyed with molybdenum tungsten cobalt and vanadium
- Chromium content in the range C 0.82-0.95 with Cr 3.80-4.50 and Mo 4.75-5.25
- Fine evenly distributed carbides through the conventional wrought structure
Certification
- Mill test certificate supplied with each shipment
Manufacturing
How It Is Made and Processed
Melting and rolling of the cobalt bearing high speed steel
Annealing to leave the material machinable for tool blanking
Cutting to the ordered blank size within 0-1000mm
Milling or grinding of the surface where ordered
Quenching and tempering to the working hardness
Punching and bending where the part calls for it
Marking and export packing with corrosion protection
Quality Control
Checks Before It Ships
- Mill test certificate raised against the ordered high speed steel grade
- Chemical composition checked against the stated element ranges
- Hardness verified after heat treatment against the 64-66 HRC target
- Blank dimensions checked against the cutting list before grinding
- Surface condition inspected as raw milled or ground per the order
- Oiled and wrapped packing checked before container loading
Customization
What We Can Change on Your Order
- Blanks cut to size within the 0-1000mm range
- Surface supplied raw milled or ground to your allowance
- Annealed for machining or quenched and tempered to working hardness
- Grade designation quoted as 1.3243 M35 HS6-5-2-5 SKH55 or W6Mo5Cr4V2Co5
- Punched or bent parts where the tool design requires it
Comparison
1.3243 high speed steel Against the Alternatives
| HSS M2 high speed steel | 1.3243 is described as a better tool steel than HSS M2 because of its ability to carry 5% cobalt, which is what holds hardness at the hot working edge. |
|---|---|
| Uncoated carbon tool steel | Carbon tool steel loses hardness quickly as the edge warms, while this grade keeps red hardness and high heat resistance under cutting load. |
| Solid carbide cutting tools | High speed steel tolerates interrupted cuts and less rigid setups where carbide chips, and it can be reground in a normal tool room. |
| Higher cobalt powder metallurgy grades | This conventional grade is described as effective and economically priced, which is why it is the most commonly used high speed steel grade rather than a specialty purchase. |
Use Guide
Specifying Handling and Welding Notes
- Order annealed material where the tool is machined before hardening and heat treated stock where it is ground only
- Plan heat treatment to reach the 64-66 HRC working hardness the grade is rated for
- Leave a grinding allowance when ordering milled surface so the finished geometry can be ground true
- Use this grade where edge temperature is the limit rather than where only abrasion matters
- Keep stock oiled and dry in store since high speed steel will rust like any tool steel
- Quote the chemical ranges and the grade name together when matching an existing tool specification
Questions Buyers Ask
1.3243 high speed steel FAQ
How is 1.3243 different from ordinary M2 high speed steel?
It is a molybdenum mix cobalt based grade and its ability to have 5% cobalt is what makes it a better tool steel than HSS M2 for hot cutting edges.
What hardness can we expect after heat treatment?
The grade is rated to generate hardness up to 64-66 HRC after heat treatment, which is what makes it suitable for drills reamers and gear cutters.
Which designations are the same material?
1.3243 M35 HS6-5-2-5 SKH55 and W6Mo5Cr4V2Co5 all refer to this grade. Quote whichever appears on your tool drawing.
What sizes do you supply?
Thickness runs to 0-1000mm and size is customized, so blanks can be cut to your tool dimensions rather than bought as full stock lengths.
Can we get it ground or does it come as raw material?
Surface is available as raw material, milled or ground. Choose milled or ground when you want to cut down the preparation work in the tool room.
What is the chemical composition?
The stated ranges are C 0.82-0.95, W 5.50-6.50, Cr 3.80-4.50, Mo 4.75-5.25, V 1.75-2.15, Si 0.20-0.45, Mn 0.15-0.40, P 0.030 and S 0.030.
Do you provide a certificate and samples?
A mill test certificate ships with the material and samples are available. Send the grade, size and surface condition you want to evaluate.
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