Is 1.2311 the same as P20?

They are close equivalents, not identical: 1.2311 carries higher manganese (1.30–1.60%) and lower molybdenum than AISI P20. For most plastic mold applications they are interchangeable.

Does 1.2311 need heat treatment after machining?

No. It is supplied prehardened to 280–325 HB and used as-machined. Surface treatments such as nitriding can be added for wear resistance.

Grades · Mold Steel · 1.2311

1.2311

Data verified

1.2311 is a prehardened Cr-Mn-Mo plastic mold steel, the European workhorse for injection molds and die holders. It is delivered ready to machine at 280–325 HB, with uniform hardness through large sections.

Hardness280–325 HB

DIN1.2311

AISIP20 (close)

GB3Cr2Mo

CategoryMold Steel

Chemical composition

Element	Content (%)
C	0.28–0.40
Si	0.20–0.40
Mn	1.30–1.60
P	≤0.035
S	≤0.035
Cr	1.80–2.10
Mo	0.15–0.25

Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.

Properties

Delivery condition	Prehardened
Hardness	280–325 HB
Tensile strength	950–1100 MPa
Density	7.85 g/cm³
Thermal conductivity	34 W/m·K

Heat treatment

Supplied prehardened. If re-hardening is required: quench 840–870 °C in oil, temper 550–620 °C.

Equivalent grades

Standard	Designation
din	1.2311
aisi	P20 (close)
gb	3Cr2Mo

Compare side by side: 1.2311 vs P20 · 1.2311 vs 1.2312 · 1.2311 vs 1.2738

Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.

Applications & Processing

Applications: Plastic injection molds, blow molds, die holders, extrusion dies, large mold bases.

Processing: Good machinability in the prehardened state; can be polished, textured, nitrided or hard-chrome plated. Weld repair with matching filler is routine.

FAQ

Is 1.2311 the same as P20?: They are close equivalents, not identical: 1.2311 carries higher manganese (1.30–1.60%) and lower molybdenum than AISI P20. For most plastic mold applications they are interchangeable.
Does 1.2311 need heat treatment after machining?: No. It is supplied prehardened to 280–325 HB and used as-machined. Surface treatments such as nitriding can be added for wear resistance.

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Source: DIN / EN published grade ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.