Corten Steel Plate
Atmospheric corrosion resistant plate that builds its own protective rust instead of paint
Specifications
Alloy Steel Sheet
1.2311 P20 Plastic Injection Mold Steel
Pre hardened low alloy mold steel that goes straight to machining without heat treatment
1.2311 and 718 are designations for the versatile low alloy pre-hardened tool steel most often called P20, where the P stands for plastic. Mold makers building plastic injection molds, die casting dies and mold frames specify it for its combination of toughness, wear resistance and machinability, and for the way it holds hardness at elevated temperatures. Because it arrives pre-hardened it can go straight into mold processing with no heat treatment step, which shortens the construction period and removes the distortion risk that comes with hardening a finished cavity. Grades are supplied as 1.2311, 3Cr2Mo, 35CrMo7, 618, 718 and P20 so a drawing written to any of those calls out the same plate.
- Product Name — Mold steel
- Grade — 1.2311 3Cr2Mo 35CrMo7 618 718 P20
- Condition — Pre-hardened ready for mold processing
- Thickness — 0-1000mm
- Size — Customized size
Why It Is Specified
Key Benefits of 1.2311/718 Mold Steel
Supplied Pre Hardened Ready for Mold Processing
The steel is delivered in a pre-hardened state and can be used directly for mold processing without heat treatment. That takes a whole stage out of the build schedule.
Clean Steel for Polished and Etched Cavities
The steel is pure enough for plastic molds that require polishing or etching, which is what a textured or optical cavity surface depends on.
Dense Structure After Forging and Rolling
Forging and rolling produce a dense structure, and the material is ultrasonically inspected with no pores and no surface defects.
Machinability and Mirror Polishing Performance
It machines well and takes a mirror polish, so cavity cutting and the polishing sequence that follows both run without fighting the material.
Hardness Retained at Elevated Temperature
The grade keeps its hardness at elevated temperature, which is why it is used for die casting dies as well as injection tooling.
Toughness Under Clamping and Injection Load
Toughness and wear resistance together let the mold plate carry clamp tonnage and injection pressure over a long production life.
Problems It Solves
What This Material Removes From Your Process
Heat Treatment Adding Weeks to a Mold Build
Sending a machined cavity out for hardening extends the program and risks movement in the quench. Pre-hardened supply removes the operation entirely.
Polishing Defects Showing Up in the Cavity
Inclusions and porosity appear as pits once a cavity is polished or etched. The steel is refined for polishing work and checked ultrasonically for pores and surface defects.
Molds Softening in Hot Running Tools
A tool that loses hardness as it heats wears at the gate and parting line. This grade is chosen because it retains hardness at elevated temperatures.
Waiting on Plate Sizes That Do Not Match the Drawing
Standard plate rarely matches a mold plate drawing. Material is cut from 0-1000mm stock to your plate list before it ships.
Application Scenarios
Where It Is Used
Plastic Injection Mold Cavities and Cores
Cavity and core blocks for injection tooling where the surface finish of the part comes directly off the steel.
Mold Bases and Mold Frames
Frames and plates that hold the cavity stack square under clamp load through millions of cycles.
Die Casting Dies
Die casting tooling where the steel has to keep its hardness while the die runs hot.
Textured and Etched Tool Surfaces
Cavities that are chemically etched for grain, which need a steel clean enough to take an even texture.
Mirror Polished Optical and Clear Part Tooling
Lens covers, clear housings and cosmetic parts where the cavity is polished to a mirror finish.
Mold Repair and Insert Replacement
Replacement inserts cut from stock so a damaged section of a running mold can be remade without rebuilding the tool.
Who It Is For
Buyers Who Specify This Product
- Injection mold makers buying pre-hardened plate for cavity and core blocks
- Mold base manufacturers cutting frames and plates to standard and custom sizes
- Die casting toolmakers specifying a grade that holds hardness at working temperature
- Product engineers approving tool steel for cosmetic parts that need mirror polish or etch
- Mold maintenance workshops holding stock for insert replacement on running tools
- Tool steel distributors supplying P20 plate to regional mold shops
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 | Mold steel |
|---|---|
| Grade | 1.2311 3Cr2Mo 35CrMo7 618 718 P20 |
| Condition | Pre-hardened ready for mold processing |
| Thickness | 0-1000mm |
| Size | Customized size |
| Technique | Annealed quenched and tempered |
| Surface | Raw material milling grinding |
| Inspection | Ultrasonic inspection no pores no surface defects |
| Application | Plastic molds and mold frames |
| Place of Origin | China |
| Processing Service | Bending welding decoiling cutting punching |
| Certificate | Mill test certificate |
| Sample | Available |
Technical Features
- Grades 1.2311 3Cr2Mo 35CrMo7 618 718 and P20
- Low alloy pre-hardened plastic mold tool steel
- Supplied ready for mold processing without further heat treatment
- Thickness 0-1000mm supplied to customized size
- Delivery condition annealed or quenched and tempered
- Surface as raw material milled or ground
- Ultrasonically inspected with no pores and no surface defects
- Bending welding decoiling cutting and punching available
Materials
- Low alloy chromium molybdenum plastic mold steel
- Designations 1.2311 3Cr2Mo 35CrMo7 618 718 and P20
- Forged and rolled to a dense structure before machining
- Supplied in the pre-hardened state
Certification
- Mill test certificate supplied with each shipment
Manufacturing
How It Is Made and Processed
Steel making and forging to mold plate section
Rolling to close the structure through the thickness
Heat treatment to the pre-hardened delivery condition
Ultrasonic inspection for internal soundness
Cutting to the ordered mold plate sizes
Milling or grinding the faces where ordered
Rust protection marking and export packing
Quality Control
Checks Before It Ships
- Mill test certificate raised for the ordered grade
- Ultrasonic inspection for pores and internal defects
- Surface examined for defects before the plate is cut
- Plate dimensions checked against the mold plate list
- Pre-hardened condition confirmed before dispatch
- Rust preventive and packing checked at loading
Customization
What We Can Change on Your Order
- Mold plates cut to the sizes on your mold base drawing
- Surface supplied as raw material milled or ground
- Thickness selected across the 0-1000mm range
- Six sides milled where the plate goes straight to cavity machining
- Holes drilled or punched before shipment
- Marking to the designation your mold shop uses
Comparison
1.2311/718 Mold Steel Against the Alternatives
| Annealed tool steel hardened after machining | Annealed stock has to be hardened once the cavity is cut, which adds lead time and movement risk, while pre-hardened plate is machined and used as delivered. |
|---|---|
| Cold work die steel such as D2 | Cold work die steel is built for blanking wear at ambient temperature, whereas this grade is made for cavity work and holds hardness as the mold runs hot. |
| Stainless mold steel | Stainless grades are chosen for corrosive resins and water line corrosion, while P20 covers general plastic tooling at lower material cost. |
| Structural steel used for mold frames | Structural plate deflects under clamp load and does not polish, whereas this grade carries the load and takes a mirror finish on the same plate. |
Use Guide
Specifying Handling and Welding Notes
- Confirm on the order whether the plate is supplied raw milled or ground because a milled plate saves a squaring setup
- Stress relieve after heavy roughing on large cavity blocks so the plate stays flat through finishing
- Work up through polishing grits without skipping a stage to reach a mirror finish without leaving scratches under the shine
- Preheat before any weld repair on a pre-hardened plate and temper the repair area afterward
- Keep water line drilling clear of the cavity surface so the wall thickness carries injection pressure
- Ask for the mill test certificate so the grade is filed with the mold build documentation
Questions Buyers Ask
1.2311/718 Mold Steel FAQ
Do we need to heat treat 1.2311 after machining the cavity?
No. It is supplied pre-hardened and can be used directly for mold processing, which is what shortens the construction period on a mold build.
Are 718 and P20 the same steel as 1.2311?
They are designations for the same low alloy plastic mold steel, along with 3Cr2Mo, 35CrMo7 and 618, so a drawing calling any of them is filled from the same plate.
Will this grade take a mirror polish or an etched texture?
The steel is pure enough for molds that require polishing or etching, and it is noted for its machinability and mirror polishing performance.
How do you check the plate for internal defects?
Plate is ultrasonically inspected after forging and rolling, with no pores and no surface defects accepted before it ships.
What plate thickness can you cut for mold bases?
Thickness covers 0-1000mm and size is customized, so mold plates and frames are cut to your drawing rather than bought as standard sizes.
Does the grade hold up in a hot running tool?
It retains hardness at elevated temperatures, which is why it is used for die casting dies as well as plastic injection molds.
Can you supply one insert blank as a sample?
Samples are available. Confirm the section size and surface condition and we will advise what can be released for the trial.
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