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1.2085 Material: Mechanical & Process Property Parameter Guide

Do not choose steel grades only by name without checking data. European grade 1.2085 Material (X33CrS16) has clear limits on hardness, strength and machining performance. This guide only lists practical data: mechanical values, thermal physical indexes, machinability ratings and property shifts under different heat treatments. Charts and simple notes help engineers for direct reference.

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1.2085 Material
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1.2085

Core Mechanical Property Data of 1.2085 Material

 
The table below shows key mechanical figures for pre-hardened 1.2085 (28–34 HRC). Data for annealed and quenched states are covered in the later heat treatment section.
 
Property IndexPre-hardened ValueUnitExplanation
Hardness28–34 / 280–325HRC / HBReady-to-use, no extra heat treatment needed
Tensile Strength900–1100MPaMedium-high strength mold steel level
Yield Strength750–900MPaYield ratio ~0.82, good rigidity
Elongation12–18%Better toughness than high carbon steel at same hardness
Impact Toughness15–25J/cm²Top level toughness among sulfur-added mold steels
Elastic Modulus~210GPaMatches most common mold steels

Three Key Points of 1.2085 Material:

 
  1. 1.2085 hits medium-high strength range. The 28–34 HRC balance delivers both wear resistance and easy machining. Hardness below 28 HRC drops tensile strength fast; above 34 HRC brings obvious brittleness.
  2. 12–18% elongation ranks top for sulfur-bearing mold steel. Its 16% chromium and medium-low carbon (0.28–0.38%) create a tougher base than high carbon steel.
  3. Sulfur content 0.05–0.10% improves cutting performance but slightly lowers transverse impact toughness. Watch thin cross sections for deep thin-walled molds.

Hardness Ranges & Application of 1.2085 Material

 
1.2085 does not stay fixed at 28–34 HRC. Four distinct hardness groups form under different heat treatment cycles.
 
Heat Treatment StateHardness RangeSuitable UsesExplanation
Annealed≤250 HBMolds requiring post heat treatmentSoft, easy to machine, low cracking risk after welding
Pre-hardened28–34 HRCStandard factory stock, direct useChoice for 90% of mold buyers
Quenched48–50 HRCHeavy wear working conditionsBrittle; tempering required before service
Tempered28–45 HRCCustom hardness demandsFinal hardness controlled by temper temperature

Simple selection logic:

 
  • Mass production & tight lead time: Pick pre-hardened stock for immediate use.
  • Molds needing later welding repair: Choose annealed grade, then quench & temper after welding.
  • Ultra-high wear demand (glass fiber filled plastic molding): Buy annealed steel, quench to 48–50 HRC then medium temper to 42–45 HRC.
     

    Avoid re-quenching pre-hardened steel. Saved processing cost cannot offset cracking risk and uneven hardness issues.

Thermal Conductivity, Expansion & Heat Treatment of 1.2085 Material

Thermal Conductivity

Thermal conductivity ~25 W/(m·K): Mid-range for martensitic stainless steel. 40% slower heat transfer than P20 (~40 W/(m·K)), slightly lower than H13 (~28 W/(m·K)). Preheat molds 10–15% longer than P20, but steady heat holding after warming. Normal injection cycle works with well-designed cooling channels.

Thermal Expansion

Thermal expansion coefficient ~11×10⁻⁶ /K (20–200°C): Stable value, far lower than austenitic stainless steel (16–18×10⁻⁶/K), nearly equal to P20. A 500mm mold block expands roughly 0.33mm when heated from room temperature to 80°C. Fits standard tolerance ±0.1–0.5mm for most plastic parts; calculate expansion compensation for precision molds over 500mm long.

Heat Treatment Temperatures

Ac₁ ≈820°C (start of austenite transformation)

 

Ac₃ ≈950°C (full austenitization temperature)

 

Heat to 1000–1050°C during quenching to fully dissolve carbide particles.

 

Ms ≈250°C (martensite transformation start point). Martensite forms once cooling below 250°C in oil quench, reaching full martensite structure with 48–50 HRC at room temperature.

 

Milling, EDM & Welding Performance of 1.2085 Material

Excellent machinability is 1.2085’s core advantage. Sulfur (0.05–0.10%) acts as built-in lubricant: clean chip breaking, no material sticking on cutters. Cutter service life rises 30–50% vs sulfur-free grades like 1.2316 at identical hardness.
 

Recommended CNC cutting parameters for pre-hardened 28–34 HRC stock

 
  • Rough milling: Cutting speed 80–120 m/min, feed per tooth 0.08–0.15 mm, cutting depth 1–2 mm. Use TiAlN coated solid carbide end mills.
  • Finish milling: Cutting speed 120–160 m/min, feed per tooth 0.03–0.06 mm, cutting depth 0.3–0.5 mm.
     

    Machining 1.2085 feels similar to tempered 40Cr (25–30 HRC), smooth and efficient.

 

EDM performance of 1.2085 Steel

Moderate electrical conductivity with stable spark discharge. Copper electrode loss rate sits at 0.5–1.0%. Note the thin white recast layer (5–20 μm) after EDM: extremely hard and brittle. Remove fully via fine machining or grinding, or micro-cracks and surface peeling will appear during mold operation.
 

Welding rules

 
  • Annealed stock: No preheating needed, slow cool after welding.
  • Pre-hardened stock: Preheat to 200–300°C, then stress relief temper at 500–550°C right after welding. Skipping preheating pushes cracking rate over 80% due to uneven hardness in heat affected zones.
     

    Use ER316L wire or special filler wire matching 1.2085 chemical composition.

 

Horizontal Comparison: 1.2085 vs P20 vs 1.2316

 
Below is direct performance comparison for the three most common plastic mold steel grades.
 
Comparison Item1.2085 MaterialP20 (3Cr2Mo)1.2316 (3Cr17NiMo)
Hardness Range28–34 HRC28–32 HRC28–34 HRC
Corrosion Resistance★★★ (15–17% Cr)★ (2% Cr, no rust protection)★★★★★ (16–18% Cr + Mo)
Machinability★★★★★ (sulfur added)★★★★★★★ (easy sticking to cutters)
Thermal Conductivity~25 W/(m·K)~40 W/(m·K)~25 W/(m·K)
Cost Level★★ (baseline price)★ (30–40% cheaper)★★★ (25–40% higher cost)
Best ApplicationInjection molding with mild corrosionDry-condition plastic moldingHeavy corrosion, high surface cleanliness demand

Summary of 1.2085 vs P20 vs 1.2316

  • P20 costs less but cannot resist rust. PVC or flame retardant ABS molds will develop surface pits within half a year.
  • 1.2316 delivers top overall performance yet costs more and machines slowly.
  • 1.2085 balances all demands: reliable anti-corrosion from 16% chromium, much faster cutting speed than 1.2316, and 25–40% lower price than 1.2316. It is the most cost-effective choice for mild-corrosion mold projects with limited budget

FAQ:

Q1: How does temper temperature change 1.2085 hardness?

A: 200°C temper → ~48 HRC; 400°C → ~42 HRC; 550°C → ~35 HRC; 650°C → ~28 HRC. Higher temper temperature creates softer steel. Minor secondary hardening (1–2 HRC hardness rise) may occur at 450–500°C from chromium carbide precipitation, far less obvious than molybdenum grades like 1.2316.

A: Its ductile-brittle transition temperature (DBTT) ranges -20°C ~ -40°C, far lower than regular workshop temperature (30–80°C). No low-temperature brittleness risk for standard molding jobs. Switch to nickel-alloy steel (1.2316 or austenitic stainless steel) if molds work below -30°C freezing conditions.

A: Gas nitriding or ion nitriding works well. Nitride layer hits 900–1100 HV with depth 0.1–0.3 mm, boosting surface wear resistance but slightly reducing anti-corrosion performance (chromium consumed to form chromium nitride).

PVD coatings (TiN, CrN) fit perfectly for 1.2085. Coating temperature 400–500°C matches its temper window without shifting base hardness. Coating raises material cost by 15–25%; run trial production first to check wear demand before mass coating.

Conclusion

Talk to Keyspark Steel engineers if you need 1.2085 material or 1.2085 equivalent for mold selection. We hold 20 years of special steel manufacturing experience, helping you match steel data with real production needs to avoid wrong material picks.

📧 Email: Sales@keysparksteel.com
📱 Mobile/WhatsApp: +86 150 2405 6480

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