AISI 81B45 Steel Flange

1,We Manufacturing processes are primarily classified into four types: 1:Forging, 2:Casting, 3:Cutting, 4:Rolling. 2,We can manufacture in accordance with these standards. Standards: GB Series (Chinese Standards), JB Series (Machinery Standards), HG Series (Chemical Industry Standards), ASME B16.5 (American Standards), BS4504 (British Standards), DIN (German Standards), and JIS (Japanese Standards). Internationally, there are two primary systems of pipe flange standards: the European system, represented by the German DIN standards (including those of the former Soviet Union), and the American system, represented by the US ANSI pipe flange standards. Other common standards include: the Chinese Ministry of Machinery Industry standards (JB series), the Ministry of Chemical Industry standards (HG series), the Chinese National Standard *GB/T 9112–9124-2010 Steel Pipe Flanges*, as well as US standards (ASME B16.5), British standards (BS4504), German standards (DIN), Japanese standards (JIS), and marine standards (CBM), among others. The nominal pressure ratings for the PN series are designated by "PN" and comprise the following nine levels: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160. The nominal pressure ratings for the Class series are designated by "Class" and comprise the following six levels: Class150, Class300, Class600, Class900, Class1500, and Class2500. Flange Classification 1. **According to Chemical Industry Standards:** Flanges are classified as follows: Plate Flat Welding Flange (PL), Necked Flat Welding Flange (SO), Necked Butt Welding Flange (WN), Integral Flange (IF), Socket Welding Flange (SW), Threaded Flange (Th), Butt Welding Ring Loose Flange (PJ/SE), Blind Flange (BL), Flat Welding Ring Loose Flange (PJ/PJ), and Lined Blind Flange (BL(s)). 2. **According to Petrochemical (SH) Industry Standards:** Flanges are classified as follows: Threaded Flange (PL), Butt Welding Flange (WN), Flat Welding Flange (SO), Socket Welding Flange (SW), Loose Flange (LJ), and Blind Flange (no specific designation). 3. **According to Machinery (JB) Industry Standards:** Flanges are classified as follows: Integral Flange, Butt Welding Flange, Plate Flat Welding Flange, Butt Welding Ring Plate Loose Flange, Flat Welding Ring Plate Loose Flange, Lap Joint Ring Plate Loose Flange, and Blind Flange. 4. **According to Connection Method/Type:** Flanges are classified as follows: Plate Flat Welding Flange, Necked Flat Welding Flange, Necked Butt Welding Flange, Socket Welding Flange, Threaded Flange, Blind Flange, Necked Butt Welding Ring Loose Flange, Flat Welding Ring Loose Flange, Ring-Type Joint (RTJ) Flange and Blind Flange, Large-Diameter Plate Flange, Large-Diameter High-Neck Flange, Figure-8 Blind Plate, Butt Welding Ring Loose Flange, etc. 5. **According to the Component Being Connected:** Flanges can be classified into Vessel Flanges and Pipe Flanges. 6. **According to Structural Type:** Flanges include Integral Flanges, Threaded Flanges, Flat Welding Flanges, Butt Welding Flanges, Lap Joint (Loose/Swivel) Flanges, and Blind Flanges. A flange—also referred to as a flange plate or rim—is a component used to connect shafts to one another, or, more commonly, to join the ends of pipes. Flanges are also utilized at the inlet and outlet ports of equipment to facilitate connections between two devices—for instance, the flange on a speed reducer. A "flange connection" or "flanged joint" refers to a detachable joint assembly comprising three interconnected elements—a flange, a gasket, and bolts—that together form a sealed structural unit. In the context of piping systems, a "pipe flange" specifically denotes a flange used for plumbing within the installation; when applied to equipment, it refers to the inlet or outlet flange of that specific device. Flanges feature a series of holes through which bolts are inserted to securely fasten the two flanges together, while a gasket placed between the flanges ensures a leak-proof seal. Flanges are broadly categorized into three types: threaded (screw-in) flanges, welded flanges, and clamp-type flanges. Flanges are invariably used in pairs; threaded flanges are suitable for low-pressure piping applications, whereas welded flanges are required for systems operating at pressures exceeding 4 kilograms per square centimeter. A sealing gasket is inserted between the two flange plates, which are then firmly secured using bolts. The thickness of a flange—as well as the specifications of the bolts used to fasten it—vary depending on the specific pressure rating required for the application. When connecting equipment such as water pumps or valves to piping systems, the corresponding connection points on these devices are often manufactured in the shape of a matching flange; this method of attachment is also referred to as a "flange connection." Generally, any connecting component that utilizes bolts to join and seal the perimeters of two flat surfaces—such as the joints in ventilation ducts—is termed a "flange"; such components may collectively be classified as "flange-type parts." However, since such a connection often constitutes merely a *portion* of a larger device—for instance, the interface between a flange and a water pump—it would be inappropriate to classify the entire water pump itself as a "flange-type part." Conversely, smaller components—such as valves—that feature such flanged interfaces may indeed be appropriately categorized as "flange-type parts." -:- For detailed product information, please contact sales. -: AISI 81B45 Steel Flange Product Information -:- For detailed product information, please contact sales. -: AISI 81B45 Steel Flange Synonyms -:- For detailed product information, please contact sales. -:

AISI 81B45 Steel Product Information -:- For detailed product information, please contact sales. -: ## **Product Specification: AISI 81B45 Boron-Treated Hardenability Steel** ### **Product Designation** * **Standard Name:** AISI 81B45 / SAE 81B45 * **UNS Number:** H50450 * **Type:** Medium-Carbon, Boron-Treated Alloy Steel * **Primary Processing:** Typically supplied hot-rolled or cold-drawn, annealed or normalized for machining. * **Key Feature:** **Boron addition** for enhanced hardenability at low alloy cost. ### **Overview** AISI 81B45 is a medium-carbon, **boron-treated alloy steel** belonging to the SAE "81Bxx" series. The defining characteristic of this grade is the intentional addition of a minute amount of **boron (typically 0.0005% - 0.003%)**, which drastically increases the hardenability of the steel with only a minimal increase in cost. This allows it to achieve through-hardening properties comparable to more highly alloyed steels, making it a **cost-effective alternative** for components requiring good strength and toughness in larger cross-sections. It is primarily used in the quenched and tempered condition. --- ### **1. Chemical Composition (Typical % by Weight, SAE/AISI Standard)** The composition is based on a standard medium-carbon manganese steel, with boron as the key performance enhancer. | Element | Content (%) | Role & Effect | | :--- | :--- | :--- | | **Carbon (C)** | 0.43 - 0.48 | Provides the fundamental capacity for strength and hardness through martensite formation upon quenching. | | **Manganese (Mn)** | 0.75 - 1.00 | Provides base hardenability and solid solution strengthening. The range is optimized to work synergistically with boron. | | **Phosphorus (P)** | ≤ 0.040 | Impurity; kept low. | | **Sulfur (S)** | ≤ 0.040 | Impurity; standard low level. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer and strengthens the ferrite matrix. | | **Boron (B)** | 0.0005 - 0.003 | **Core Element.** Segregates to austenite grain boundaries during quenching, dramatically increasing hardenability by delaying the transformation of austenite to softer phases (ferrite, pearlite). | | **Other Elements**| Trace amounts of Al, Ti, or Zr may be present to "protect" the boron by tying up nitrogen, ensuring its effectiveness. | | **Iron (Fe)** | Balance | | *Note: The "81" prefix historically indicated a specific Ni-Cr-Mo base, but in the boron "B" series, it primarily denotes a specific hardenability range. The chemistry is essentially that of a 15Bxx series steel with adjusted manganese.* --- ### **2. Physical & Mechanical Properties** **A. Physical Properties (Annealed/Normalized State)** * **Density:** 7.85 g/cm³ (0.284 lb/in³) * **Elastic Modulus (E):** ~205 GPa (29.7 x 10⁶ psi) * **Poisson's Ratio:** 0.29 * **Thermal Conductivity:** ~48 W/m·K * **Coefficient of Thermal Expansion:** 11.5 x 10⁻⁶ /K (20-100°C) **B. Mechanical Properties (As-Supplied, Annealed)** * **Hardness (Brinell):** 179 - 217 HB * **Tensile Strength:** 585 - 725 MPa (85 - 105 ksi) * **Yield Strength:** ~415 MPa (60 ksi) min. * **Elongation:** 20% min. * **Machinability:** Fair to good in the annealed condition. **C. Mechanical Properties (After Quenching & Tempering)** *Properties are highly dependent on section size and tempering temperature.* * **Typical Heat Treatment:** Austenitize at 830-850°C (1525-1560°F), **oil quench**, and temper. * **Surface Hardness (As-Quenched):** Up to 58-60 HRC. * **Tempered Hardness Range:** 25 - 50 HRC (Widely adjustable). * **Tensile Strength (e.g., at ~300-350 HB):** 1000 - 1200 MPa (145 - 174 ksi). * **Core Toughness:** Good at moderate hardness levels; impact strength decreases at very high hardness/strength levels typical of through-hardened steels. * **Key Advantage:** Achieves a deeper uniform hardness ("harder core") in larger sections than a standard 1045 or 1541 steel at similar cost. --- ### **3. Product Applications** AISI 81B45 is selected for medium-to-heavy section components where good through-hardening is needed economically. It often replaces more expensive Cr-Mo or Ni-Cr-Mo steels. * **Automotive Components:** * **Shafts:** Axle shafts, torsion bars, steering components, and less critical drive shafts. * **Fasteners:** High-strength bolts, pins, and studs. * **Gears & Forgings:** Medium-duty gears, differential cases, and other forged parts. * **Agricultural & Off-Highway Machinery:** * Implement parts, linkage components, and hydraulic cylinder rods. * **General Machinery:** * Spindles, pins, bushings, and lever arms requiring wear resistance and strength. * **Construction Equipment:** * Bucket teeth adapters, linkage pins, and other high-wear, high-strength parts. --- ### **4. International Standards & Designations** The boron steel concept is used globally, but the "81B45" designation is specific to the SAE system. Other standards have their own numbering for boron steels. | Standard System | Designation | Notes / Key Comparison | | :--- | :--- | :--- | | **SAE / AISI (USA)** | **SAE 81B45** | The standard designation. "B" denotes boron treatment. | | **UNS (USA)** | **H50450** | Unified Numbering System for boron steels. | | **ASTM (USA)** | **ASTM A304** (for H-band grades) or **ASTM A29** | Often supplied as a standard grade bar. | | **DIN / EN (Germany/EU)** | No direct equivalent. Conceptually similar to **~1.5530 (38MnB5)** or **1.5525 (34MnB5)**. | European boron steels are common (xxMnBx), but the exact manganese/carbon balance of 81B45 is not directly mirrored. | | **JIS (Japan)** | No direct equivalent. | Similar boron-treated steels exist (e.g., **S45C-B**), but are not standardized with an identical "81" prefix composition. | | **GB (China)** | **40MnB** or **45MnB** | These are the standard Chinese boron steels and are the **closest functional equivalents** to AISI 81B45. | --- ### **Key Considerations & Processing** 1. **Hardenability vs. Toughness:** Boron significantly increases hardenability but does not inherently improve toughness. The toughness of 81B45 is largely a function of its carbon and manganese content and the final tempered microstructure. 2. **Heat Treatment Sensitivity:** Boron's effectiveness is highly sensitive to austenitizing temperature and time. Overheating can reduce its hardenability-enhancing effect. 3. **Weldability:** Fair to poor. The carbon content and high hardenability make it prone to cracking in the heat-affected zone (HAZ). Pre-heat and post-heat treatments are usually necessary. 4. **Economic Advantage:** Its primary benefit is achieving the hardenability of a more expensive alloy steel (like a 41xx or 86xx series) at a cost closer to a plain carbon-manganese steel. ### **Summary** **AISI 81B45** is a **cost-optimized, high-hardenability steel** made possible by boron microalloying. It fills an important niche in engineering design, providing the ability to through-harden larger cross-sections for applications requiring good strength and wear resistance, where core toughness requirements are moderate and cost is a significant factor. While not as versatile or tough as higher-alloy grades like 4140 or 4340, it serves as a reliable and economical workhorse material for a wide range of automotive and general industrial components. Its closest global analogues are the **GB 40MnB/45MnB** grades. -:- For detailed product information, please contact sales. -: AISI 81B45 Steel Specification Dimensions Size： Diameter 20-1000 mm Length <4143 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 81B45 Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 81B45 Steel Flange -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 81B45 Steel Flange -:- For detailed product information, please contact sales. -:

Packing of AISI 81B45 Steel Flange -:- 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 Flange 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 614 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