1.2312 Plastic Mould Steel
Sulphur-alloyed, pre-hardened (quenched and tempered) plastic mould steel (40CrMnMoS8-6, P20+S). It is machined directly at its supplied hardness of 280–325 HB and needs no heat treatment. Its machinability is very good, and it is used for mould frames and bolsters, clamping plates and plastic moulds.
Grade and sizes
1.2312
Sulphur-alloyed, pre-hardened (quenched and tempered) plastic mould steel. Machined directly in the as-supplied condition, with very good machinability.
Composition: steelmakers’ data sheets (not listed as a separate grade in EN ISO 4957)
- FORM
- Round bar · flat bar / block
- SIZE
- On request; cut to the size you need
- SUPPLY CONDITION
- Pre-hardened (quenched and tempered), 280–325 HB
- WORKING HARDNESS
- Used at the supplied hardness (approx. 28–34 HRC)
Chemical composition (%)
Ranges from steelmakers’ data sheets; P max. 0.030.
| GRADE | C | Si | Mn | Cr | Mo | S |
|---|---|---|---|---|---|---|
| 1.2312 | 0.35–0.45 | 0.30–0.50 | 1.40–1.60 | 1.80–2.00 | 0.15–0.25 | 0.05–0.10 |
Heat treatment (guide values)
Compiled from steelmakers’ data sheets; actual values depend on the section size and furnace conditions.
| PROCESS | TEMPERATURE | COOLING AND RESULT |
|---|---|---|
| As supplied | – | Pre-hardened, 280–325 HB · no heat treatment needed |
| Stress relieving | 30–50 °C below the last tempering temperature | Furnace cooling |
| Hardening (if required) | 840–870 °C | Oil or salt bath at 180–220 °C · max. approx. 50 HRC |
| Nitriding | – | Possible |
Weight calculator
Calculate the weight from the size, or the length and number of pieces needed for a target weight. Your selections are added to the quote message automatically.
Size: Ø50 × 200 mm, quantity: 1 (theoretical ~3.08 kg)
Technical data
Chemical composition, mechanical properties and material certificates are available on request.
+90 530 671 13 78 · info@pointmetal.com.tr
Applications
- Plastic mould cavities with a technical surface finish
- Frames and bolsters for plastic and die-casting moulds
- Clamping plates and base plates
- Tool holders
- Press-brake dies
- Hydroforming tools
- Plastic extrusion dies
- Machine components and fixtures
Frequently asked questions
Does 1.2312 need hardening before use?
No. 1.2312 is supplied quenched and tempered to about 280–325 HB (≈ 29–34 HRC), so it can be machined and used as delivered. After heavy roughing, a stress-relief anneal below about 550 °C helps keep the part dimensionally stable.
What is the difference between 1.2312 and 1.2311?
The chemistry is almost the same, but 1.2312 has added sulphur. This makes chips break better and tools last much longer, at the cost of surface quality: for mirror polishing or photo-etched texture, 1.2311 is chosen, or 1.2738 for large sections.
Can 1.2312 be nitrided?
Yes. Gas, plasma or salt-bath nitriding raises the surface hardness to roughly 700–850 HV. The process temperature is kept below the steel’s tempering temperature (about 550 °C or lower) so that the core keeps its hardness.
Does 1.2312 rust?
Yes. It is a low-alloy steel with about 2 % chromium, so it can rust in humid conditions and in cooling channels. Where corrosion resistance is needed, 1.2085 is used for mould bases and 1.2316 or 1.2083 for cavities.
What are the designations for 1.2312?
1.2312: 40CrMnMoS8-6, AISI ≈ P20+S. Any of these designations can be used in your enquiry; we will match the correct material.
Why can the invoiced weight differ from the calculated weight?
The calculator gives the theoretical weight. The actual weight varies with dimensional tolerances and cutting allowance; we invoice on the actual weight as weighed.
What information should I send for a quote?
We only need the size (diameter × length), quantity and delivery location. If you fill in the calculator above, these details are added to the WhatsApp message automatically.