AISI Type S2 Tool Steel Wire

AISI Type S2 Tool Steel Wire, austenitized 845°C (1550°F), brine quenched to 15 HRC Product Information -:- For detailed product information, please contact sales. -: AISI Type S2 Tool Steel Wire, austenitized 845°C (1550°F), brine quenched to 15 HRC Synonyms -:- For detailed product information, please contact sales. -:

AISI Type S2 Tool Steel, austenitized 845°C (1550°F), brine quenched to 15 HRC Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type S2 Tool Steel (UNS T41902) - Annealed/Unhardened Condition Profile** ## **Overview** This profile describes **AISI S2 (UNS T41902)** tool steel in a **soft, non-hardened condition**, nominally referenced as achieving 15 HRC after processing. It is crucial to understand that **S2 is not used as a functional tool material at 15 HRC**. This hardness level represents either: 1. The **fully annealed, supply condition** of the steel prior to final heat treatment by the toolmaker. 2. A theoretical or misinterpreted endpoint of an improper heat treatment cycle. As a shock-resisting tool steel, S2 derives its value from being heat treated to harness its exceptional silicon-enhanced toughness at working hardness levels typically between **50-58 HRC**. This document will clarify the material's properties in its intended supply state and explain why a hardness of 15 HRC is not a target for service. ## **1. Chemical Composition (Nominal %)** The composition remains the same regardless of hardness state. | Element | Content (%) | Primary Function | |---------|------------|------------------| | **Carbon (C)** | 0.40 - 0.55 | Provides hardenability potential. In annealed state, exists as spheroidized carbides in a ferrite matrix. | | **Silicon (Si)** | 0.90 - 1.20 | **Key alloyant.** In annealed state, strengthens the ferrite matrix, improving machinability chip control and providing a foundation for future toughness. | | **Molybdenum (Mo)** | 0.30 - 0.60 | Increases potential hardenability and refines grain structure. | | **Manganese (Mn)** | 0.30 - 0.50 | Supports hardenability potential. | | **Iron (Fe)** | Balance | Base metal. | ## **2. Physical & Mechanical Properties (Annealed/15 HRC Condition)** | Property | Typical Value / Condition | |----------|--------------------------| | **Hardness** | **~15-20 HRC** (Brinell ~85-100 HB). This is a **very soft, machinable state**. | | **Microstructure** | **Spheroidized Carbides in a Ferrite Matrix.** Carbides (cementite, Fe₃C) are rounded and dispersed to minimize hardness and maximize machinability. | | **Tensile Strength** | ~500-600 MPa (73-87 ksi) | | **Yield Strength** | ~350-450 MPa (51-65 ksi) | | **Elongation** | **Very High** (>20%). Highly ductile. | | **Impact Toughness** | High, but not meaningful as the material is not in its designed service microstructure. | | **Wear Resistance** | **Very Poor.** Would gall and deform immediately under tooling loads. | | **Machinability** | **Excellent.** This is the primary reason for supplying S2 in this condition. | | **Formability** | Good; can be cold formed to a degree. | | **Primary Purpose in This State** | To be easily **machined, shaped, drilled, and tapped** into the final tool geometry prior to hardening and tempering. | ## **3. International Standards & Cross-References** *Standards refer to the grade itself, not this specific soft condition.* | Standard | Designation | |----------|------------| | **UNS** | T41902 | | **AISI/ASTM** | S2 (ASTM A681) | | **ISO** | **~55SiMo8** (ISO 4957) | | **DIN (Germany)** | **1.3520** | ## **4. Clarification on the "Austenitized & Quenched to 15 HRC" Specification** The described process of "austenitizing at 845°C and brine quenching to 15 HRC" is **technically contradictory and not a valid industrial practice**. * **Austenitizing at 845°C:** This is a correct first step to put the steel into solution for hardening. * **Brine Quenching:** This is an aggressive, fast quench intended to produce a hard martensitic structure. * **Result of 15 HRC:** If a fully austenitized piece of S2 is brine quenched and achieves only 15 HRC, it indicates a **catastrophic heat treatment failure**: 1. **Severe Under-Hardening:** The quench was too slow (e.g., insufficient agitation, wrong medium) or the section size was too large for the brine quench, resulting in a non-martensitic transformation (e.g., coarse pearlite or bainite). 2. **Full Annealing Instead of Quenching:** The part may have been cooled extremely slowly after austenitizing, effectively re-annealing it. **In summary, this is not a designed heat treatment but a description of a failed hardening attempt or a misunderstanding.** The proper sequence would be: **Machine in Annealed State (~15-20 HRC) -> Austenitize at 845°C -> Quench (Brine/Oil) -> Temper to desired service hardness (e.g., 50-58 HRC).** ## **5. Correct Application & Heat Treatment Path** **Valid Application Pathway for AISI S2:** 1. **Procurement:** Material is supplied **Annealed** at ~15-20 HRC. 2. **Machining:** All shaping, milling, drilling, and threading is performed in this soft state. 3. **Heat Treatment (Typical for Service):** * **Preheat:** 650-700°C (1200-1290°F) * **Austenitize:** 845-870°C (1550-1600°F) * **Quench:** Agitated brine, water, or oil. **(Brink quenching is valid for achieving high hardness, not 15 HRC)**. * **Temper Immediately:** Temper at **205-425°C (400-800°F)** to achieve a service hardness of **50-58 HRC**, where S2 exhibits its famed toughness. 4. **Final Grinding/Finishing** (if required, due to scale or minimal distortion). ## **6. Conclusion** **AISI S2 at 15 HRC is not a product specification; it is a supply condition or a heat treatment error.** The immense value of S2 as a shock-resisting steel is only realized after proper quenching and tempering to harness the synergistic effect of its silicon and carbon in a hardened martensitic or bainitic microstructure. **Key Takeaway:** Do not specify "S2 at 15 HRC" for a functioning tool component. Specify **"S2, annealed for machining"** if you are fabricating, or specify the final required **hardness and toughness properties** (e.g., "S2, heat treated to 55 HRC minimum, for chisel application") if ordering a finished tool. --- **Disclaimer:** This profile is provided to correct a potential misunderstanding regarding the application of AISI S2 tool steel. The steel is designed to be hardened for service. Any component found at 15 HRC after an attempted hardening cycle has failed to transform correctly and will lack the strength, wear resistance, and designed toughness required for tool applications. Always follow established heat treatment guidelines from the material producer. -:- For detailed product information, please contact sales. -: AISI Type S2 Tool Steel, austenitized 845°C (1550°F), brine quenched to 15 HRC Specification Dimensions Size： Diameter 20-1000 mm Length <6757 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: AISI Type S2 Tool Steel, austenitized 845°C (1550°F), brine quenched to 15 HRC Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type S2 Tool Steel Wire, austenitized 845°C (1550°F), brine quenched to 15 HRC -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type S2 Tool Steel Wire, austenitized 845°C (1550°F), brine quenched to 15 HRC -:- For detailed product information, please contact sales. -:

Packing of AISI Type S2 Tool Steel Wire, austenitized 845°C (1550°F), brine quenched to 15 HRC -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Wire drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 3228 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition