Si vous êtes aux prises avec la corrosion des moisissures causée par des produits chimiques, humidité, ou des plastiques durs (comme le PVC), JIS S136 mold steel is the solution you need. This premiumstainless mold steel combines exceptional corrosion resistance with outstandingpolissabilité miroir—making it ideal for medical, nourriture, et moules pour produits de consommation haut de gamme. Dans ce guide, nous allons décomposer ses propriétés clés, applications du monde réel, étapes de fabrication, and how it compares to other materials—so you can build molds that last and deliver flawless parts.
1. Material Properties of JIS S136 Mold Steel
JIS S136’s unique performance comes from its high-chromium composition and carefully tuned properties. Let’s explore these in detail:
1.1 Composition chimique
The elements in JIS S136 work together to boost corrosion resistance, polissabilité, et durabilité. Below is its standard composition (per JIS G4404):
| Élément | Gamme de contenu (%) | Key Role |
|---|---|---|
| Carbone (C) | ≤ 0.08 | Low content reduces carbide formation, enhancing corrosion resistance and polishability. |
| Manganèse (Mn) | ≤ 1.00 | Improves hardenability without compromising corrosion resistance. |
| Silicium (Et) | ≤ 1.00 | Enhances strength and resistance to oxidation in high-temperature molds. |
| Chrome (Cr) | 12.00 – 14.00 | The primary element for corrosion resistance; forms a protective chromium oxide layer on the surface. |
| Molybdène (Mo) | 0.40 – 0.60 | Boosts corrosion resistance in acidic environments; improves high-temperature strength. |
| Vanadium (V) | 0.10 – 0.30 | Refines grain structure, enhancing mirror polishability and dimensional stability. |
| Soufre (S) | ≤ 0.030 | Minimized to avoid surface defects (par ex., pits) during polishing. |
| Phosphore (P.) | ≤ 0.030 | Kept low to prevent brittleness and ensure uniform corrosion resistance. |
1.2 Propriétés physiques
These properties determine how JIS S136 behaves in manufacturing and use—such as heat transfer and resistance to warping. All values are measured at room temperature unless noted:
- Densité: 7.85 g/cm³ (consistent with most stainless steels, making it easy to calculate mold weight).
- Point de fusion: 1450 – 1510 °C (high enough to withstand forging and heat treatment without deformation).
- Conductivité thermique: 25 Avec(m·K) (lower than carbon steel, but sufficient for even cooling in plastic injection molds).
- Coefficient de dilatation thermique: 11.5 × 10⁻⁶/°C (depuis 20 à 600 °C; low expansion ensures stabilité dimensionnelle in heat cycles).
- Specific Heat Capacity: 460 J/(kg·K) (efficient at absorbing heat, reducing plastic cooling time in molds).
1.3 Propriétés mécaniques
JIS S136 is often supplied in a pre-hardened state (HRC 30–35) for convenience, but it can also be heat-treated to higher hardness. Below are its typical properties after standard heat treatment (trempe + tempering at 500 °C):
| Propriété | Valeur typique | Test Standard | Pourquoi c'est important |
|---|---|---|---|
| Dureté (CRH) | 30 – 35 (pre-hardened); 45 – 50 (fully hardened) | JIS Z2245 | Balanced hardness—pre-hardened for easy machining; fully hardened for high-wear molds. |
| Résistance à la traction | ≥ 1000 MPa | JIS Z2241 | Handles the pressure of plastic injection or die casting without deformation. |
| Limite d'élasticité | ≥ 850 MPa | JIS Z2241 | Resists permanent damage, keeping molds dimensionally stable for thousands of cycles. |
| Élongation | ≥ 15% | JIS Z2241 | Bonne ductilité, reducing the risk of cracking during mold clamping or polishing. |
| Résistance aux chocs (Charpy V-notch) | ≥ 45 J. (à 20 °C) | JIS Z2242 | Excellent toughness—prevents mold failure from sudden impacts (par ex., part jams). |
| Fatigue Strength | ~450 MPa (10⁷ cycles) | JIS Z2273 | Resists wear from repeated use (key for high-cyclefood packaging molds or medical device molds). |
1.4 Autres propriétés
- Résistance à la corrosion: Excellent. The high chromium content forms a passive oxide layer that resists rust, acides, et produits chimiques (par ex., PVC additives or medical disinfectants)—far better than standard mold steels.
- Résistance à l'usure: Good to Very Good. Molybdenum and vanadium form hard carbides; for high-wear applications, fully hardening (HRC 45–50) or nitriding boosts wear resistance further.
- Usinabilité: Équitable. Pre-hardened JIS S136 (HRC 30–35) is machinable with carbide tools, but it’s slower to machine than P20 mold steel due to its stainless properties.
- Trempabilité: Very Good. It hardens evenly across thick sections (jusqu'à 60 mm), so large molds have consistent performance.
- Mirror Polishability: Outstanding. Low carbon and fine grain structure let it achieve mirror finishes (Ra ≤ 0.01 µm)—critical for consumer product molds (par ex., contenants cosmétiques) ou des dispositifs médicaux.
- Stabilité dimensionnelle: Excellent. Low thermal expansion and uniform hardening prevent mold warping during machining or heat cycles.
2. Applications of JIS S136 Mold Steel
JIS S136’s corrosion resistance and polishability make it a top choice for demanding industries. Voici ses utilisations les plus courantes, avec des exemples réels:
2.1 Medical Device Molds
- Exemples: Molds for plastic syringes, poignées d'instruments chirurgicaux, or diagnostic test kits.
- Why it works: Corrosion resistance stands up to frequent disinfection (par ex., ethanol or steam), while mirror polishability ensures parts are free of bacteria-trapping defects. Un États-Unis. medical manufacturer used JIS S136 for syringe molds—mold life increased by 300% contre. standard steel.
2.2 Food Packaging Molds
- Exemples: Molds for plastic food containers, bouchons de boissons, or disposable cutlery.
- Why it works: Resists corrosion from food acids (par ex., tomato sauce, citrus) and cleaning chemicals. A European packaging company used JIS S136 for yogurt cup molds—mold maintenance dropped by 50%.
2.3 PVC or Corrosive Plastic Molds
- Exemples: Molds for PVC pipes, vinyl siding, or chemical storage containers.
- Why it works: PVC releases corrosive gases during molding—JIS S136’s stainless properties prevent mold rusting. A Chinese manufacturer used JIS S136 for PVC pipe molds—mold failure from corrosion stopped entirely.
2.4 High-End Consumer Product Molds
- Exemples: Molds for smartphone casings, pots cosmétiques, or luxury watch components.
- Why it works: Mirror polishability delivers premium surface finishes, while corrosion resistance keeps molds looking clean. A Japanese electronics brand used JIS S136 for smartphone case molds—part defect rates fell to 0.2%.
3. Manufacturing Techniques for JIS S136 Mold Steel
Turning JIS S136 into high-performance molds requires specialized processing to preserve its corrosion resistance and polishability. Voici une ventilation étape par étape:
- Fusion: Matières premières (iron, chrome, molybdène, etc.) are melted in an electric arc furnace (AEP) with strict control to keep carbon and impurity levels low—critical for corrosion resistance.
- Fonderie: Molten steel is poured into ingot molds or continuous casters to form slabs. Refroidissement lent (50–100 °C/hour) prevents internal defects and ensures uniform grain structure.
- Forgeage: Slabs are heated to 1100–1200 °C and pressed/hammered into mold blanks (par ex., 500x500x200 mm for injection molds). Forging improves toughness and eliminates voids.
- Traitement thermique:
- Pre-hardened Cycle: Anneal (800–850 °C) → Quench (1000–1050 °C) → Temper (550–600 °C) → Final hardness HRC 30–35.
- Fully Hardened Cycle: Anneal → Quench (1000–1050 °C) → Temper (400–450 °C) → Final hardness HRC 45–50.
- Usinage: Use carbide tools for pre-hardened JIS S136 (HRC 30–35). Reduce cutting speeds by 20–30% vs. P20 steel to avoid tool wear. CNC machines are recommended for tight tolerances (±0,001 mm).
- Polissage: To achieve mirror finish:
- Start with 400-grit sandpaper to remove machining marks.
- Progress to 1000-grit, 3000-grincer, and 8000-grit sandpaper.
- Finish with diamond paste (1–3 μm) using a soft felt pad—this ensures no scratches compromise the mirror surface.
- Traitement de surface (Facultatif):
- Nitruration: Heat to 500–550 °C in a nitrogen-rich environment. Adds a hard surface layer (HRC 60–65) pour augmenter la résistance à l'usure (ideal for die casting molds).
- Galvanoplastie: Chrome or nickel coating for extra corrosion protection in harsh chemical environments.
4. Étude de cas: JIS S136 in Medical Syringe Molds
A German medical device manufacturer faced a crisis: their standard steel syringe molds were rusting after 50,000 cycles due to steam sterilization, leading to contaminated syringes and product recalls. They switched to JIS S136, and here’s what happened:
- Processus: Molds were forged, pre-hardened to HRC 32, machined to syringe cavity geometry, polished to Ra 0.008 µm, and passivated (pour améliorer la résistance à la corrosion).
- Résultats:
- Mold life increased to 250,000 cycles (400% amélioration) with no rust.
- No more recalls—syringes met strict medical cleanliness standards.
- Maintenance time dropped by 60% (no need to repair rust damage).
- Why it works: JIS S136’s chromium oxide layer resisted steam and disinfectants, while its mirror polishability eliminated bacteria-trapping surface defects—solving both corrosion and contamination issues.
5. JIS S136 vs. Other Mold Materials
How does JIS S136 compare to common alternatives for corrosion-prone or high-precision applications? Let’s evaluate key properties:
| Matériel | Résistance à la corrosion | Mirror Polishability (Ra μm) | Usinabilité | Coût (contre. JIS S136) | Idéal pour |
|---|---|---|---|---|---|
| Acier pour moules JIS S136 | Excellent | ≤ 0.01 | Équitable | 100% | Medical molds, PVC molds, emballage alimentaire |
| P20 Pre-hardened Steel | Pauvre | ≤ 0.05 | Excellent | 50% | General plastic molds (no corrosion risk) |
| Acier de moule JIS NAK80 | Bien | ≤ 0.01 | Excellent | 80% | High-polish molds (no harsh chemicals) |
| Aluminum Mold Materials (7075) | Pauvre | ≤ 0.02 | Excellent | 60% | Moules prototypes (faible volume, pas de corrosion) |
| Acier au carbone (1045) | Very Poor | ≥ 0.10 | Excellent | 30% | Faible coût, low-precision molds |
Key takeaway: JIS S136 is the only material that combines excellent corrosion resistance with mirror polishability. It’s more expensive than P20 or NAK80, but the cost is justified for corrosion-prone applications like medical or PVC molds.
Yigu Technology’s View on JIS S136 Mold Steel
Chez Yigu Technologie, JIS S136 is our go-to for clients in medical, nourriture, and chemical industries. Its corrosion resistance solves the biggest pain point—premature mold failure from rust or chemicals—while its polishability ensures flawless parts. We often recommend pre-hardened JIS S136 for faster production and pair it with passivation or nitriding to enhance performance. For businesses prioritizing durability and compliance (par ex., normes médicales), JIS S136 isn’t just a material—it’s a way to avoid costly recalls and build long-lasting molds.
FAQ About JIS S136 Mold Steel
1. Can JIS S136 be used for hot runner systems in plastic injection molds?
Oui! JIS S136’s high-temperature stability (jusqu'à 500 °C) and corrosion resistance make it ideal for hot runners—especially for PVC or other corrosive plastics. We recommend fully hardening it to HRC 45–50 or adding a nitrided layer to boost wear resistance.
2. Is JIS S136 more difficult to machine than P20 steel?
Oui, JIS S136 is slower to machine than P20 because of its stainless properties (higher chromium content increases cutting force). To improve machinability, use sharp carbide tools, vitesses de coupe inférieures (100–120 m/min vs. 150–180 m/min for P20), and high-quality cutting fluid.
3. Do I need to passivate JIS S136 after machining?
Passivation (treating with nitric acid) is optional but recommended—especially for medical or food molds. It strengthens the chromium oxide layer, enhancing corrosion resistance by 20–30%. For non-critical applications (par ex., consumer product molds), thorough cleaning after machining may be sufficient.