Scope:
Domestic steel mold：3Cr2Mo（P20）
Standard: GB / T 1299-1985Hot work tool steel, is the introduction of P20 in the United States Department of the carbon Cr-Mo steel, plastic mold. For the production of plastic mold and die casting low melting point metal mold material. This steel has good cutting and mirror polishing performance.
How to use:
P20 pre-hardened to 285-330HB (30-36HRC), and Sweden 618 German GS-2311 status rather, can be directly used for molding processing, and has good dimensional stability characteristics, pre-hardened steel can meet the general purpose demand, die life die times of up to 50W
Features:
● pure steel vacuum degassing refining process for polishing or etch processing requirements of the plastic mold.
● Pre-hard state supply without heat treatment can be used directly in the mold, shorten the construction period.
● by forging rolling processing, compact structure, 100% ultrasonic inspection, non-porous, needle defects.
Uses:
● thermoplastic injection molding, extrusion die.
● thermoplastic blow molding.
● Overloading the main components of the mold.
● Cold structural parts.
● commonly used in the manufacture of television chassis, washing machine, refrigerator shells, buckets and so on.
3cr2mo physical properties
Hardening process:
To improve die life 800,000 times or more modes can be implemented on pre-hardened steel, quenched and tempered low and hard to achieve. Quenching when the first warm-up 2-4 hours of 500-600 ℃, 850-880 ℃ and then holding a certain time (at least 2 hours), put the oil in the oil cooled to 50-100 ℃ air-cooled, quenched hardness of up to 50 -52HRC, in order to prevent cracking should be immediately 200 ℃ tempering treatment, tempering, the hardness can be maintained for more than 48HRC
Nitriding:
Nitrided surface tissue obtained high hardness, surface hardness after nitriding to achieve 650-700HV
(57-60HRC) Mold life is up to 100 million times more dense nitride layer with a tissue and smooth characteristics, mold mold release and anti-corrosive wet air and lye can improve.
Chemical composition:
Carbon C: 0.28 ~ 0.40
Si Si: 0.20 ~ 0.80
Manganese Mn: 0.60 ~ 1.00
Sulfur S: ≤ 0.030
Phosphorus P: ≤ 0.030
Chromium Cr: 1.40 ~ 2.00
Ni: to allow the residual content of ≤ 0.25
Copper Cu: to allow the residual content of ≤ 0.30
Mo Mo: 0.30 ~ 0.55
Mechanical properties:
● Heat treatment and microstructure specifications:
● Delivery status: the annealed steel, hot rolled delivery.
Code No. or abroad just: HP-AMA
Pre-hardened plastic mold steel;
The P20 steel is improved, pre-hardened hard 27 ~ 34HRC, uniform hardness, good wear resistance.
Used: the TV shell, telephones, vacuum cleaner housing, drinking fountains, plastic mold.
Thermal processing
3Cr2Mo steel thermal processing are shown in Table 4-4-5
Tang Ning metal to provide raw materials Figure 32CrMo
3Cr2Mo steel thermal processing
| Project | Heating temperature / ℃ | On forging temperature / ℃ | Final forging temperature / ℃ | Cooling |
| Ingot | 1180～1200 | 1130～1150 | ≥850 | Cold pit |
| Billet | 1120～1160 | 1070～1110 | ≥850 | Cold or slow sand cold |
