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."
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Bethlehem Steel Flange RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, Steel Flange plate Product Information
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Bethlehem Steel Flange RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, Steel Flange plate Synonyms
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Bethlehem Steel RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, steel plate Product Information
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## **Product Datasheet: Bethlehem Steel RQC ASTM A678 RQC80 Steel Plate**
**Product Overview**
Bethlehem Steel RQC ASTM A678 RQC80 is a premier, high-strength, quenched and tempered (Q&T) structural steel plate from the proprietary RQC (Rapid Quenched Carbon) series. Engineered to deliver a superior balance of **80 ksi minimum yield strength**, exceptional low-temperature toughness, and excellent weldability, this grade represents the high-strength tier of the RQC family. Utilizing Bethlehem's optimized heat treatment process, it achieves a fine-grained, tempered martensitic microstructure that provides outstanding resistance to fracture and fatigue. The RQC80 is specifically designed for critical applications where maximum strength-to-weight ratio and structural integrity under extreme conditions are required. This plate is available in thicknesses ranging from **3/16 inch (4.8 mm) to 3/4 inch (19.1 mm)**.
**Key International Standards & Specifications**
* **Primary Performance Standard:** **ASTM A678 / A678M** - While "RQC80" is a proprietary Bethlehem Steel designation, the product is manufactured to meet and exceed the mechanical and toughness requirements aligned with the 80 ksi yield strength category within the ASTM A678 framework.
* **Proprietary Designation:** The **"RQC80"** trademark signifies Bethlehem Steel's specialized production route for achieving high toughness at this strength level, differentiating it from standard A678 Grade D.
* **Mandatory Supplementary Requirements:** Certification typically included stringent impact testing, aligning with:
* **ASTM A6 Supplementary Requirement S1 (Charpy V-Notch Impact Testing):** Guaranteed with high minimum energy values at low temperatures (typically **-50°F / -46°C**).
* **ASTM A6 S5 (Maximum Carbon Equivalent):** Strictly controlled to ensure superior weldability for its strength class.
* **Industry Context:** Often specified as a premium alternative to **ASTM A678 Grade D** where guaranteed ultra-high toughness was non-negotiable, or as a more weldable and tough counterpart to ultra-high-strength alloy steels.
**Chemical Composition (Weight % - Typical RQC80 Aim for Thickness ≤ 0.75")**
Chemistry is meticulously balanced to achieve the high hardenability needed for full martensitic transformation upon quenching in this thickness range, while maintaining lean alloying for weldability and toughness.
| Element | Typical RQC80 Aim / Range | Key Purpose |
| :--- | :--- | :--- |
| **Carbon (C)** | 0.14 - 0.19% | Lowered to maximize toughness and weldability while providing a strong martensitic base. |
| **Manganese (Mn)** | 1.20 - 1.50% | Primary agent for strength and hardenability. |
| **Phosphorus (P)** | ≤ 0.015% | Ultra-low for enhanced fracture resistance. |
| **Sulfur (S)** | ≤ 0.008% | Ultra-low for improved ductility and reduced anisotropy. |
| **Silicon (Si)** | 0.15 - 0.30% | Deoxidizer. |
| **Aluminum (Al)** | 0.02 - 0.05% | Grain refiner (fine grain practice). |
| **Nickel (Ni)** | 0.40 - 0.70% | Significantly improves hardenability and, crucially, low-temperature toughness without a severe carbon equivalent penalty. |
| **Chromium (Cr)** | 0.40 - 0.65% | Enhances hardenability and tempering resistance. |
| **Molybdenum (Mo)** | 0.15 - 0.25% | Critical for achieving full hardenability and suppressing temper embrittlement. |
| **Vanadium (V)** | 0.03 - 0.07% | Contributes to strength via precipitation. |
| **Boron (B)** | 0.001 - 0.003% | Trace addition to significantly boost hardenability efficiently. |
| **Carbon Equivalent (C.E. IIW)** | Typically 0.48 - 0.55 | Well-managed for an 80 ksi Q&T steel, facilitating controlled welding. |
**Physical & Mechanical Properties**
| Property | RQC80 Minimum/Target Requirement | Typical Performance |
| :--- | :--- | :--- |
| **Yield Strength (Min)** | 80 ksi (550 MPa) | 85 - 95 ksi (586 - 655 MPa) |
| **Tensile Strength** | 95 - 115 ksi (655 - 795 MPa) | 100 - 110 ksi (690 - 759 MPa) |
| **Elongation in 2" (Min)** | 16% | 17 - 20% |
| **Yield-to-Tensile Ratio** | -- | Typically 0.85 - 0.88 |
| **Modulus of Elasticity** | ~29,000 ksi (200 GPa) | ~29,000 ksi (200 GPa) |
| **Density** | 0.284 lb/in³ (7.85 g/cm³) | 0.284 lb/in³ (7.85 g/cm³) |
| **Charpy V-Notch Toughness (Hallmark)** | **Exceptionally High (e.g., 35-50 ft-lb @ -50°F / -46°C)** | The defining achievement of the RQC80 grade. It delivers impact values often associated with much lower strength steels, providing a massive safety margin against brittle fracture. |
| **Key Feature** | **Ultra-High Toughness at 80 ksi Yield:** Successfully combines the highest commonly specified structural yield strength (80 ksi) with Charpy toughness levels that rival many 50-60 ksi steels, enabling breakthrough designs for critical, weight-sensitive applications in severe environments. |
**Product Applications**
Bethlehem Steel RQC80 was specified for the most highly stressed components in safety-critical structures and equipment operating under dynamic or impact loading, often in low-temperature conditions.
* **Advanced Mobile Equipment:** Critical boom and arm sections, pivot points, and main frames for the largest excavators, cranes, and forestry equipment where weight savings directly translate to performance and payload.
* **Offshore & Marine Structures:** Critical node joints, tendon sleeves, and other highly constrained welds in offshore oil & gas platforms and ice-class vessel components.
* **Defense & Aerospace:** Armor vehicle structural members, landing gear components, and launch system structures requiring high strength with certified toughness.
* **Energy Infrastructure:** Critical sections for advanced reactor components, high-pressure manifolds, and high-stress parts in hydroelectric turbines.
* **Heavy Transportation:** Key structural members in heavy-haul truck frames, logging equipment, and specialized railcar components.
**Advantages & Fabrication Notes**
* **Optimized Weldability for its Strength Class:** While requiring strict low-hydrogen procedures, its controlled chemistry makes it significantly more weldable than other 80 ksi Q&T steels with higher carbon or alloy content. Preheat and interpass temperature control (typically 300-400°F / 149-204°C) are essential.
* **Unmatched Fracture Resistance:** Provides an unparalleled combination of strength and toughness, effectively pushing the boundary of the structural steel performance envelope.
* **Fatigue Performance:** The clean, homogeneous Q&T microstructure offers excellent resistance to crack initiation under cyclic loading.
* **Formability Considerations:** Cold forming is limited and requires large bend radii. Hot forming is not recommended without subsequent re-austentizing, quenching, and tempering.
* **Legacy Product Note:** The RQC80 was a flagship high-performance product of Bethlehem Steel. Modern equivalents include proprietary **"HSLA 80"** or **"HY-80" type grades** from specialty plate producers, and advanced **"S690QL"** or **"S690Q"** grades per EN 10025-6, though chemistry and processing may differ.
**Disclaimer:**
This datasheet describes the historical **Bethlehem Steel RQC80** product. For current projects requiring this performance level, engineers must specify **80 ksi min YS, 95-115 ksi UTS, and guaranteed high Charpy V-Notch values at the design low temperature** (e.g., **40 ft-lb min @ -50°F**). Additionally, specify **maximum CE** (e.g., 0.55) to ensure weldability. Engage with mills specializing in high-performance Q&T plate to source an equivalent material, such as a plate meeting **ASTM A678 Grade D with enhanced supplemental toughness requirements** or a mill-proprietary grade. Fabrication requires welding procedure qualification on representative material, and all thermal processes must follow the producer's strict guidelines.
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Bethlehem Steel RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, steel plate Specification
Dimensions
Size：
Diameter 20-1000 mm Length <4675 mm
Size:We can customized as required
Standard：
Per your request or drawing
We can customized as required
Properties（Theoretical）
Chemical Composition
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Bethlehem Steel RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, steel plate Properties
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Applications of Bethlehem Steel Flange RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, Steel Flange plate
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Chemical Identifiers Bethlehem Steel Flange RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, Steel Flange plate
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Packing of Bethlehem Steel Flange RQC ASTM A678 RQC80 3/16 to 3/4 in. thick, Steel Flange plate
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Standard Packing:
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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 1146 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
