Material 1.2085 Selection & Purchasing Risk Avoidance Guide

Corrosion working environment

Will your mold form plastics like PVC or flame retardant ABS that release acid gas? If yes, material 1.2085 is the right pick. Its 16% chromium forms a protective film to stop acid corrosion, and the mold cavity stays free of pits for 2 to 3 years.

If you only mold non-corrosive plastics such as PP and PE, P20 or 718 is cheaper, cutting material cost by 30-40%.

Expected mold service life

For molds that need more than 500,000 shots, pre-hardened material 1.2085 can be used directly. Without ESR treatment, mold life limits only come from cooling maintenance and process settings, not the steel itself.

For molds under 200,000 shots, P20 meets all demands.

Polishing demand

If mirror polish over 1000# is required, standard material 1.2085 only reaches 800#. Its 0.05-0.10% sulfur makes sulfide bits that leave tiny pits during polishing.

You have to pick ESR grade for mirror finish, costing an extra 30-50%. Standard grade is a better steel choice for regular molds without mirror polish needs.

Internal machining ability

Do you own carbide cutters and stable CNC programs? If yes, use pre-hardened material 1.2085 (28-34 HRC) directly to save steps.

If not, buy annealed stock and do heat treatment yourself, which adds 5-7 days and an extra cost of 500-800 RMB per ton.

Standard stock plate sizes: width 210-810mm, length 3000-5800mm.

80mm thickness is the split line of hot rolling and forging: plates thinner than 80mm use hot rolling to lower cost; plates 80mm and thicker must go through forging to guarantee sound inner structure.

If you order 100mm thick plates, the quotation must include forging cost, 15-25% higher than hot rolled plates.

Bars with diameter 20-80mm are hot rolled; bars over 80mm are forged.

Bars thicker than 200mm need upset and draw steps to ensure inner quality. When you order Φ250mm big bars for mold cores, ask sellers to confirm if they use 3-upset-3-draw forging process.

C

0.28–0.38%. Too low leads to insufficient hardness (＜28HRC); too high causes cracking easily.

Si

0.40–0.80%. Deoxidize and refine grain, stabilize material, prevent porosity defects.

Mn:

0.80–1.20%. Offset brittleness caused by sulfur, improve machinability and impact resistance.

P

≤0.030%. Harmful impurity; material becomes scrap if over limit, poor toughness and prone to fracture.

S(Key mark to distinguish genuine material)

0.05–0.10% . Exclusive feature of 1.2085; fake material if sulfur content is low (≈0.02%).

Cr(Core element for rust resistance)

15–17%. Rust resistance fails and corrosion occurs easily if below 15%.

Ni

≤0.60%. Trace amount stabilizes structure; excess reduces hardness and wear resistance.

Mo

≤0.30%. Refine grain and stabilize performance; excess makes machining hard, material hard and brittle.

Hardness of Material 1.2085:

material 1.2085 is regular mold stock. Standard plates and round bars (thickness 20-200mm, width 210-610mm, diameter 30-200mm) are fully stocked and can ship within 3 days.

Custom non-standard sizes need production scheduling, with 15-25 days lead time.

ESR grade takes longer delivery time: the extra ESR process alone adds 5-7 days, total lead time 25-35 days.

If you use material 1.2085 monthly in stable volume, sign fixed quantity contracts with sellers for locked price, priority delivery and bulk discounts.

For occasional small orders, choose in-stock standard sizes rather than custom-made ones. Saved lead time outweighs small unit price gaps.