Alloy 52 Round Bar (W.NR 2.4478, UNS N14052)
Product Introduction
As a diligent procurement specialist, encountering this alloy 52 round bar means your project is entering the realm of high-reliability, high-performance electronics or specialised industrial applications.
Typical Application Scenarios (determining your purchasing direction):
- Vacuum Electronics and Power Electronics: The core material for ceramic-to-metal (Cer-Met) seals. Used in high-power thyristors, IGBT modules, vacuum relays, microwave tube envelopes, and electrode terminals. This is its primary application area.
- Aerospace and Military: Hermetic sealing structures for high-reliability sensors, gyroscopes, and lasers.
- Semiconductor Equipment: Certain components require high-strength, high-hermeticity connections with ceramics.
Key Tip: If your customer is a "sealing engineer" or "power electronics designer," their main concerns will be the "hermeticity," "strength," and "long-term thermal fatigue life" of the parts machined from this rod material when sealed with ceramics or glass. Everything revolves around "matching."
Please grasp the core concept: when you purchase alloy 52 rods, you're not just buying a metal rod, but rather its "perfectly matched coefficient of thermal expansion (CTE) with certain special glasses and ceramics," and the resulting stress-free, long-lasting sealing capabilities.
Procurement Specifications and Industry Standards
Based on our past successful experience procuring alloy 52 bar, your inquiry must go beyond the norm and directly address the core performance requirements. The following points should be emphasised before communicating with the supplier:
1. Clarify Material Standards and Grades:
The internationally recognised standard is ASTM F30 "Constant Elasticity, Sealing, and Thermal Bimetallic Alloys," specifically Alloy 52. We consider the unified grade to be UNS K94600. The corresponding standard in China is GB/T 15018 (4J52). It can be stated that "the chemical composition and properties are equivalent to ASTM F30 Alloy 52."
2. Specifications and Condition (Critical Requirements):
Our alloy bar inventory generally stocks sizes ranging from diameter Ф4mm to Ф600mm. We provide simple processing services, so you can freely specify the length. Please pay attention to the diameter (Dia) and tolerance (usually h11 or tighter), and length (fixed or variable).
3. Delivery Condition: Must be clearly stated in capital letters and bold: "Annealed Condition".
Also, clearly define the core performance requirements of the alloy 52 round bar (core of the technical agreement):
Must specify CTE: "The material must provide thermal expansion coefficient data matching [specify ceramic grade, such as '96% alumina ceramic'], and within the [specify temperature range, such as '25-450°C'], the average CTE should be (target value ±0.3) × 10⁻⁶/°C."
Chemical Composition Window: Specifically define the control range for nickel (Ni) content (e.g., 51.3-51.7%).
4. Special Requirements (Optional, but recommended for greater assurance):
Ultrasonic Testing: The alloy bar requires 100% UT testing to ensure no internal inclusions, cracks, or other defects. Sealing components are used in high-pressure or vacuum environments, and internal defects are catastrophic.
Surface Quality: The delivered alloy bar must be free of deep scratches, folds, and scale. A machined surface is a common requirement.
Processing difficulty and key points
(understanding the reasons for high prices)
Alloy 52 is a nickel-iron alloy with fair machinability and is relatively easy to cut. However, it is quite sticky, requiring sharp carbide tools, ample coolant, and appropriate chip breakers to achieve a good surface finish. Whether purchasing raw materials, machining simple parts, or precision-machined parts, the following points should be noted by skilled machining personnel regarding secondary processing:
Pre-sealing cleaning and oxidation treatment are core processes: Your customer (or your downstream workshop) requires strict degreasing and pickling of the processed parts, followed by pre-oxidation in a specific temperature and atmosphere to form a thin, dense oxide film on the surface. This is crucial for good bonding with the solder or glass. The supplier should be able to provide guidance.
Heat treatment must be carefully controlled: The alloy rod material is already annealed, and any subsequent heat treatment that could alter its microstructure and CTE (such as improper welding, which can compromise the matching properties) is strictly prohibited.
One-stop procurement recommendation: If your requirement is for finished sealed components (such as ceramic-metal electrodes), it is strongly recommended to find a professional ceramic-metal packaging manufacturer or a mature supply chain management company (such as Lork Group). We typically procure Alloy 52 rods, process them into parts, and complete the entire process of cleaning, oxidation, and ceramic brazing/sealing. This is far more reliable than procuring raw materials yourself and then outsourcing the subsequent processes.
For more information, please contact:
Email: susan@lorkgroup.com
WhatsApp: +86 19937075488
Chemical Composition
(Nickel content is a critical factor that directly determines the CTE [Coefficient of Thermal Expansion] and must be strictly controlled around the median value of 51.5%.)
| Weight% |
Typical values |
| Ni | 50.5 - 52.5% |
| Co | ≤ 0.50% (Impurity control) |
| Mn | 0.20 - 0.50% (deoxidation) |
| Si | ≤ 0.15% (Low silicon content is beneficial for sealing.) |
| C | ≤ 0.03% (Key harmful impurities; high levels can impair toughness and sealing properties) |
Mechanical Properties
Procurement requirements: The bar stock you purchase must be in the "annealed" condition. This is not only for ease of subsequent machining, but also because only the annealed state can provide a stable and uniform CTE (Coefficient of Thermal Expansion), which is a prerequisite for successful sealing.
| Material | (Annealed state) |
| Coefficient of thermal expansion | The average value between 20-500°C is approximately ~9.5 × 10⁻⁶/°C. |
| Tensile Strength | ≥ 520 MPa |
| Yield Strength (0.2%) | ≥ 240 MPa |
| Elongation | ≥ 30% |
| Hardness | HB 140-180 |
Lork Group Price Alert:
The price drivers for alloy 52 round bar include - nickel price (main cost). Additionally, small diameters, tight tolerances, and ultrasonic testing (UT) will increase costs.
Note the key negotiation points: The focus should not be on haggling over every penny of the unit price, but rather on "guaranteeing the accuracy of CTE data" and "establishing a technical resolution and compensation mechanism for quality issues."
Minimum Order Quantity: There is usually a MOQ(30~50/kg), calculated by weight (kilograms) or minimum diameter.
Hot Tags: Alloy 52, round bar, w.nr 2.4478, uns n14052, China alloy round bar manufacturers
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