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E: enquiry@qilumetal.com
E: enquiry@qilumetal.com
No. 18 Xiangfu Middle Road,Yuhua District, Changsha City
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1.2312 is a widely used plastic mold steel that belongs to the German standard DIN 17350. It is known for its excellent machinability, good polishability, and uniform hardness distribution. Due to its common usage and reliable performance, many countries have equivalent steel grades to DIN 1.2312, such as: P20+S from the American standard ASTM A681.
1.2312 tool steel contains chromium and manganese, which enhance its hardenability and wear resistance. The sulfur content improves machinability, making it suitable for high-precision plastic molds and tooling applications. Its pre-hardened state allows for direct machining without additional heat treatment, reducing production time and costs. This steel is commonly used in the manufacturing of injection molds, blow molds, and compression molds, particularly for producing plastic parts with high surface quality requirements.
1: Steel equivalent
Country | USA | Germany |
Standard | ASTM A681 | DIN17350 |
Grade | P20+S/P21 | 1.2312/40CrMnMoS8-6 |
2: Chemical composition
Grade | C | Si | Mn | P | S | Cr | Mo |
| 1.2312/ 40CrMnMoS8-6 | 0.35-0.45 | 0.30-0.50 | 1.40-1.60 | 0.030Max | 0.030Max | 1.80-2.00 | 0.15-0.25 |
| P21 | 0.18-0.22 | 0.20-0.40 | 0.20-0.40 | 0.030Max | 0.030Max | 0.20-0.30 | / |
3: Surface hardness and hardenability
Heat Treatment | Hardness |
| Soft Annealed(+A) | HB285Max |
| Quenched and tempred (+QT) | HRC28-32(Common Range) |
4: Supply size & Tolerance & Stock size
Product type | Size range | Length |
Hot rolled bar | Φ10-Φ190mm | 2000-5800mm |
Hot forged bar | Φ200-Φ600mm | 2000-5800mm |
Hot rolled plate/sheet | T:10-60mm; W:310-810mm | 2000-5800mm |
Hot forged plate | T:70-250mm; W:310-810mm | 2000-5800mm |
Hot Forged block | T: 260-500mm; W: 300-1000mm | 2000-5800mm |
Surface Finish | Turned | Milled | Grinding(Best) | Polished(Best) | Peeled(Best) | Black Forged | Black Rolled |
Tolerance | +0/+3mm | +0/+3mm | +0/+0.05mm | +0/+0.05mm | +0/+0.1mm | +0/+5mm | +0/+1mm |
Straighness | 1mm/1000mm max. | 3mm/1000mm max. | |||||
Qilu steel stock hot rolled bar and forged bars more than ten thousands tons every month, below our our stock size.
1): Stock diameter for hot rolled bar
10 | 12 | 15 | 18 | 20 | 22 | 25 | 28 | 30 | 32 | 35 | 38 | 40 | 45 | 50 |
55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 100 | 105 | 110 | 120 | 130 | 140 |
150 | 160 | 170 | 180 | 190 |
2): Stock diameter for hot forged bar
200 | 210 | 220 | 230 | 240 | 250 | 260 | 270 | 280 | 290 |
300 | 310 | 320 | 330 | 340 | 350 | 360 | 370 | 380 | 390 |
400 |
Since the stocks change everyday, if you want to know our stock available information, please contact our salesman.
5: Ultrasonic Test
EN10228-3 class III or Sep 1921-84 D/D
6：Steel making & Forging processing
1): Steel making process:
EF+LF+VD
EAF+LF+VD
EF+LF+VD+ESR
EAF+LF+VD+ESR
2): Forging processing:
Put the 1.2312 ingot into the furnace
Continue heating the ingot to initial temperature: 1050-1100℃
Forge the ingot, forging temperature should be not less than 850℃
Cooling in the sand or in the furnace after forging
7: Heat treatment
1): Annealed:
Heat 1.2312 steel to 780-820℃ in the furnace
Soak at this temperature in the furnace
Cooling in the furnace (≤30°C/h) to approximately 500°C, then air cooling
2): Quenching and tempering:
Heat 1.2312 steel to 840-850℃ in the furnace
Soak at this temperature in the furnace
Quench in oil
Temper steel at 500-600℃ in the furnace
Take out from furnace and cool in the air
It normally suppolied in the quenched and tempered condition with a hardnedd of about 300HB
The heating time of test pieces in a salt batch shall be as give in below table:
Total heating time of test pieces in a salt bath
Nature of steel | Hardening Time min | Tempering Time min |
Cold or hot work steels | 25 +/- 1 | 60 |
High-speed steels | 3 | Minimum 2 periods of 60 each |
If the test pieces are not heated in a salt batch, the heating time must be extended accordingly, and the times for heating give above are not valid for thicker tools.
8：Application
1.2312 is a pre-hardened plastic mold steel. It offers good machinability, polishability, and weldability, making it widely used in mold manufacturing. Main Applications of 1.2312 Steel
1. Plastic Injection Molds: manufacturing injection molds for thermoplastics and thermosets.
2. Compression Molds & Blow Molds: used for PVC, ABS, PP, PE, PC, and other engineering plastics.
3. Die-Casting Inserts (Low-Temp Alloys): used for zinc/aluminum die-casting inserts (not for high-temp alloys like magnesium/copper).
4. Mold Bases & Components
1) Core/cavity inserts, ejector pins, sliders, and guide components.
2) Used in automotive, electronics, and consumer goods molds.
5. Prototype & Low-Cost Molds
1.2312 is a widely used plastic mold steel that belongs to the German standard DIN 17350. It is known for its excellent machinability, good polishability, and uniform hardness distribution. Due to its common usage and reliable performance, many countries have equivalent steel grades to DIN 1.2312, such as: P20+S from the American standard ASTM A681.
1.2312 tool steel contains chromium and manganese, which enhance its hardenability and wear resistance. The sulfur content improves machinability, making it suitable for high-precision plastic molds and tooling applications. Its pre-hardened state allows for direct machining without additional heat treatment, reducing production time and costs. This steel is commonly used in the manufacturing of injection molds, blow molds, and compression molds, particularly for producing plastic parts with high surface quality requirements.
1: Steel equivalent
Country | USA | Germany |
Standard | ASTM A681 | DIN17350 |
Grade | P20+S/P21 | 1.2312/40CrMnMoS8-6 |
2: Chemical composition
Grade | C | Si | Mn | P | S | Cr | Mo |
| 1.2312/ 40CrMnMoS8-6 | 0.35-0.45 | 0.30-0.50 | 1.40-1.60 | 0.030Max | 0.030Max | 1.80-2.00 | 0.15-0.25 |
| P21 | 0.18-0.22 | 0.20-0.40 | 0.20-0.40 | 0.030Max | 0.030Max | 0.20-0.30 | / |
3: Surface hardness and hardenability
Heat Treatment | Hardness |
| Soft Annealed(+A) | HB285Max |
| Quenched and tempred (+QT) | HRC28-32(Common Range) |
4: Supply size & Tolerance & Stock size
Product type | Size range | Length |
Hot rolled bar | Φ10-Φ190mm | 2000-5800mm |
Hot forged bar | Φ200-Φ600mm | 2000-5800mm |
Hot rolled plate/sheet | T:10-60mm; W:310-810mm | 2000-5800mm |
Hot forged plate | T:70-250mm; W:310-810mm | 2000-5800mm |
Hot Forged block | T: 260-500mm; W: 300-1000mm | 2000-5800mm |
Surface Finish | Turned | Milled | Grinding(Best) | Polished(Best) | Peeled(Best) | Black Forged | Black Rolled |
Tolerance | +0/+3mm | +0/+3mm | +0/+0.05mm | +0/+0.05mm | +0/+0.1mm | +0/+5mm | +0/+1mm |
Straighness | 1mm/1000mm max. | 3mm/1000mm max. | |||||
Qilu steel stock hot rolled bar and forged bars more than ten thousands tons every month, below our our stock size.
1): Stock diameter for hot rolled bar
10 | 12 | 15 | 18 | 20 | 22 | 25 | 28 | 30 | 32 | 35 | 38 | 40 | 45 | 50 |
55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 100 | 105 | 110 | 120 | 130 | 140 |
150 | 160 | 170 | 180 | 190 |
2): Stock diameter for hot forged bar
200 | 210 | 220 | 230 | 240 | 250 | 260 | 270 | 280 | 290 |
300 | 310 | 320 | 330 | 340 | 350 | 360 | 370 | 380 | 390 |
400 |
Since the stocks change everyday, if you want to know our stock available information, please contact our salesman.
5: Ultrasonic Test
EN10228-3 class III or Sep 1921-84 D/D
6：Steel making & Forging processing
1): Steel making process:
EF+LF+VD
EAF+LF+VD
EF+LF+VD+ESR
EAF+LF+VD+ESR
2): Forging processing:
Put the 1.2312 ingot into the furnace
Continue heating the ingot to initial temperature: 1050-1100℃
Forge the ingot, forging temperature should be not less than 850℃
Cooling in the sand or in the furnace after forging
7: Heat treatment
1): Annealed:
Heat 1.2312 steel to 780-820℃ in the furnace
Soak at this temperature in the furnace
Cooling in the furnace (≤30°C/h) to approximately 500°C, then air cooling
2): Quenching and tempering:
Heat 1.2312 steel to 840-850℃ in the furnace
Soak at this temperature in the furnace
Quench in oil
Temper steel at 500-600℃ in the furnace
Take out from furnace and cool in the air
It normally suppolied in the quenched and tempered condition with a hardnedd of about 300HB
The heating time of test pieces in a salt batch shall be as give in below table:
Total heating time of test pieces in a salt bath
Nature of steel | Hardening Time min | Tempering Time min |
Cold or hot work steels | 25 +/- 1 | 60 |
High-speed steels | 3 | Minimum 2 periods of 60 each |
If the test pieces are not heated in a salt batch, the heating time must be extended accordingly, and the times for heating give above are not valid for thicker tools.
8：Application
1.2312 is a pre-hardened plastic mold steel. It offers good machinability, polishability, and weldability, making it widely used in mold manufacturing. Main Applications of 1.2312 Steel
1. Plastic Injection Molds: manufacturing injection molds for thermoplastics and thermosets.
2. Compression Molds & Blow Molds: used for PVC, ABS, PP, PE, PC, and other engineering plastics.
3. Die-Casting Inserts (Low-Temp Alloys): used for zinc/aluminum die-casting inserts (not for high-temp alloys like magnesium/copper).
4. Mold Bases & Components
1) Core/cavity inserts, ejector pins, sliders, and guide components.
2) Used in automotive, electronics, and consumer goods molds.
5. Prototype & Low-Cost Molds
