AISI 1078 Steel, Hot Rolled,UNS G10780

AISI 1078 Steel, Hot Rolled Bar (UNS G10780) Product Information -:- For detailed product information, please contact sales. -: AISI 1078 Steel, Hot Rolled Bar (UNS G10780) Synonyms -:- For detailed product information, please contact sales. -:

AISI 1078 Steel, Hot Rolled Bar (UNS G10780) Product Information -:- For detailed product information, please contact sales. -: ### **Product Data Sheet: AISI 1078 Steel, Hot-Rolled Bar (UNS G10780)** #### **1. Overview** AISI 1078 (UNS G10780) is a premium high-carbon, non-alloy steel supplied in the hot-rolled bar form. Characterized by its very high carbon content, it is a foundational material engineered for applications demanding **ultimate strength, hardness, and wear resistance after heat treatment**. In its as-rolled condition, it provides a cost-effective and readily machinable or forgeable starting point with inherent moderate strength. AISI 1078 is distinguished from lower-carbon grades by its exceptional capacity for deep hardening and achieving the highest levels of hardness in the quenched and tempered state, making it a preferred choice for heavy-duty tools, springs, and critical wear components. --- #### **2. Chemical Composition (AISI/SAE Standard)** The precise chemistry is the source of its superior performance. | Element | Content (%) | | :--- | :--- | | **Carbon (C)** | **0.72 - 0.85** | | **Manganese (Mn)** | 0.60 - 0.90 | | **Phosphorus (P)** | ≤ 0.040 | | **Sulfur (S)** | ≤ 0.050 | | **Silicon (Si)** | 0.15 - 0.35 | | **Iron (Fe)** | Balance | **Key Distinction:** The carbon range (0.72-0.85%) positions AISI 1078 at the upper end of standard high-carbon steels, providing maximum hardenability and final hardness potential among commonly available grades like 1060, 1065, and 1070. --- #### **3. Typical Physical & Mechanical Properties (As-Hot Rolled)** *Properties are for the "black," mill-scaled, as-rolled condition prior to any further processing.* | Property | Typical Value / Description | | :--- | :--- | | **Condition** | Hot-Rolled (Pearlitic Microstructure) | | **Density** | 7.85 g/cm³ (0.284 lb/in³) | | **Modulus of Elasticity** | 190-210 GPa (27.5-30.5 x 10⁶ psi) | | **Tensile Strength** | **650 - 800 MPa (94 - 116 ksi)** | | **Yield Strength (0.2% Offset)** | **370 - 450 MPa (54 - 65 ksi)** | | **Elongation (in 50mm)** | **~ 10 - 12%** | | **Reduction in Area** | **~ 25 - 30%** | | **Hardness** | **200 - 245 HB** (Brinell) | | **Machinability** | **Fair (~50% of AISI 1212).** Acceptable for roughing operations. Machinability improves significantly if the material is normalized or annealed. | | **Surface Finish** | Standard hot-rolled finish with adherent mill scale. | --- #### **4. Key Characteristics & Heat Treatment Response** * **Exceptional Hardenability:** The primary advantage. AISI 1078 achieves deeper and more uniform hardness upon quenching compared to lower-carbon steels. It can be hardened to **60-65 HRC**, providing exceptional wear and abrasion resistance. * **High Strength & Elastic Limit:** After proper quenching and tempering (e.g., to a spring temper of ~45-52 HRC), it develops a very high yield strength and elastic limit, making it an outstanding spring material. * **Moderate As-Rolled Ductility:** Provides sufficient formability for straightening, bending, or forging at elevated temperatures. * **Poor Weldability:** **Not recommended for welding.** The high carbon content creates a high susceptibility to heat-affected zone (HAZ) cracking, martensite formation, and loss of toughness. If welding is unavoidable, it requires stringent procedures: high preheat (400-450°C / 750-850°F), post-weld heat treatment, and use of low-hydrogen electrodes. * **Final Properties are Heat-Treatment Dependent:** The as-rolled state is a precursor; the steel's full potential is unlocked only through controlled austenitizing, quenching, and tempering. --- #### **5. Primary Product Applications** AISI 1078 hot-rolled bar is the material of choice for manufacturing the most demanding high-strength and wear-resistant components. * **Heavy-Duty Springs:** The premier application for high-stress springs: **heavy truck and railway leaf springs, large coil springs, torsion bars.** * **Forging Stock:** Ideal feedstock for closed-die forging of high-strength tools and parts: **wrenches, crowbars, hooks, agricultural tool blanks (plow shares, cultivator shovels).** * **Cutting Tools & Blades:** Used for **industrial shear blades, knives, mower and cutter bars** where maximum edge retention is required. * **Wear Parts & Shafts:** Components subjected to severe abrasion: **axles, rollers, mill pins, chain links, scraper blades, grader edges.** * **Hand Tools & Tooling:** **Chisels, punches, impact tools, and die components** that require extreme hardness. --- #### **6. Relevant International & Industry Standards** This product conforms to major international specifications for hot-rolled carbon steel bars. | Standard System | Standard Designation | Title / Scope | | :--- | :--- | :--- | | **AISI / SAE / UNS (USA)** | **1078, SAE J403, UNS G10780** | Standard Grade Designation | | **ASTM (USA)** | **ASTM A29/A29M** | Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought | | **ASTM (USA)** | **ASTM A576** | Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality (Grade 1078) | | **ASTM (USA)** | **ASTM A689** | Specification for Carbon and Alloy Steel Bars for Springs | | **DIN / EN (Germany/EU)** | **1.1231 / C75W2** | EN 10083-2: Steels for quenching and tempering. The most common direct equivalent. | | **JIS (Japan)** | **SWRH77A / SWRH77B** | High Carbon Steel Wire Rods (similar composition). For springs: **SUP3, SUP4** (JIS G4801). | | **GB (China)** | **75# / 80#** | Quality Carbon Structural Steel (GB/T 699). **65Mn** is a commonly specified spring steel alternative. | --- ### **Manufacturing & Processing Note** The standard workflow for using AISI 1078 hot-rolled bar is: 1. **Forming:** The component is shaped via **forging, hot bending, or machining** from the as-rolled bar. 2. **Heat Treatment (Mandatory for Service Performance):** * **Austenitizing:** Heat to ~790-815°C (1450-1500°F). * **Quenching:** Rapidly cool in **oil** (for complex shapes to minimize distortion/cracking) or **water** (for maximum hardness on simple shapes). * **Tempering:** **Immediately** reheat to a specific temperature (e.g., 200-500°C / 400-930°F) to relieve stresses, increase toughness, and achieve the exact hardness required. 3. **Finishing:** Final grinding or polishing may be performed. **Summary:** AISI 1078 (UNS G10780) hot-rolled bar is the quintessential high-carbon steel for extreme performance applications. It is selected when the design criteria call for the maximum attainable hardness, strength, and wear resistance from a standard, non-alloy steel. Its value lies in its transformational potential through skilled heat treatment, making it a cornerstone material for the tooling, heavy vehicle, and agricultural equipment industries. -:- For detailed product information, please contact sales. -: AISI 1078 Steel, Hot Rolled Bar (UNS G10780) Specification Dimensions Size： Diameter 20-1000 mm Length <4869 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 1078 Steel, Hot Rolled Bar (UNS G10780) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 1078 Steel, Hot Rolled Bar (UNS G10780) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 1078 Steel, Hot Rolled Bar (UNS G10780) -:- For detailed product information, please contact sales. -:

Packing of AISI 1078 Steel, Hot Rolled Bar (UNS G10780) -:- 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 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 1340 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