1J85 Strip
1J85 Strip is a cold-rolled,thin ribbon form of a high-permeability nickel-iron soft magnetic alloy,widely referred to as Permalloy 80,Mu-Metal,or Ni80Mo5.It is engineered primarily for applications that require extreme sensitivity to weak magnetic fields and elite electromagnetic shielding capabilities.
Core Magnetic Characteristics
- Ultra-High Initial Permeability:
It can achieve an initial magnetic permeability exceeding 100,000,conducting magnetic flux exponentially better than standard structural steel. - Low Coercivity & Hysteresis Loss:
It magnetizes and demagnetizes effortlessly.This prevents energy loss under rapid alternating fields. - Near-Zero Magnetostriction:
The physical dimensions do not deform when exposed to a magnetic field,ensuring structural and performance stability.
Applications of 1J85 Strip
- MRI Shielding
- Transformer Cores
- Aerospace Instruments
- Security Tags
- Circuit Shielding
- Recording Heads
- Signal Relays
- Sensor Protection
- Vehicle Sensors
- Lab Enclosures
Processing & Handling Limitations
To unleash its peak magnetic behavior,1J85 must undergo a high-temperature vacuum or dry hydrogen annealing treatment.This aligns its internal crystal grain borders.A critical drawback is that its post-annealed magnetic states are highly stress-sensitive. Dropping,bending,or vibrating the strip after heat treatment can disrupt its grain orientation and degrade its shielding performance.
We offer 1J85 strips in thicknesses ranging from 0.02 to 3.0.We offer not only stainless steel strips but also precision strips made of Hastelloy, Incoloy, Inconel, Monel, and other high-performance alloys.Our products comply with ASTM F1684, EN 10204, ISO 9001, PED 2014/68/EU, CE,and other standards.With over a decade of experience in manufacturing and import/export,we are your best wholesaler in China.
Chemical Composition of 1J85 Strip
The standard chemical composition of 1J85 Strip is governed by Chinese standard GB/T 15018.It is a classic high-permeability Ni-Fe soft magnetic alloy containing approximately 80% Nickel and 5% Molybdenum.
| Ni | Mo | Fe | Mn | Si | Cu | C | P | S |
|---|---|---|---|---|---|---|---|---|
| 79.0 – 81.0 | 4.80 – 5.20 | Balance | 0.30 – 0.60 | 0.15 – 0.30 | ≤ 0.20 | ≤ 0.03 | ≤ 0.02 | ≤ 0.02 |
The Role of Carbon and Impurities
Carbon and Sulfur are kept deliberately low.If these elements exceed limits,they precipitate out at the internal grain boundaries.These precipitates anchor magnetic domain walls,drastically driving up coercivity and destroying the alloy’s signature low-field sensitivity.
Phase Stability
At room temperature,the high percentage of Nickel traps the strip entirely within a single-phase Austenitic matrix.This continuous face-centered cubic pattern allows magnetic fields to move rapidly through the material without encountering disruptive phase changes.
Magnetostriction Nullification
The specific ratio of ~80% Ni to ~15% Fe results in near-zero magnetostriction.This means the 1J85 strip does not expand or contract when magnetized,preventing internal acoustic noise or stress-induced permeability drops.
1J85 Strip Standards & Equivalent Designations
| 1J85 (High-Permeability Soft Magnetic Crystalline Alloy) | |||||
|---|---|---|---|---|---|
| Standard / System | Equivalent Designation | Product Form | GB / GB/T (China) | GJB (Military) | GOST (Russia) |
| Chinese Standard | 1J85 | Plates, Sheets & Strips | GB/T 32286.1 | GJB 5873 | GOST 10160 |
| Russian / CIS Standard | 79NM / 81NMA (79НМ / 81НМА) | Bars & Rods | GB/T 15018 | – | GOST 10994 |
| ISO Chemical Name | Ni80Mo5Fe / Ni79Mo5 | Seamless Pipes & Tubes | – | – | – |
| UNS System | UNS N14080 | Welded Pipes & Tubes | – | – | – |
| Aviation / Aerospace | Moly-Permalloy / Supermalloy | Forgings & Rings | – | – | – |
| European / ASTM Designation | ASTM A753 Alloy 4 / DIN 2.4504 | ||||
| Generic Trade Name | Permalloy 80, HyMu 80 | ||||
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Mechanical Properties of 1J85 Strip
1J85 strip is a high-nickel soft magnetic alloy specifically engineered for exceptional magnetic permeability in weak magnetic fields.Because its final application depends entirely on its magnetic properties,its mechanical properties shift drastically depending on whether it is in the cold-rolled state or the post-annealed state.
| Mechanical Property | Cold-Rolled State (Hardened) | Post-Annealed State (Softened) |
|---|---|---|
| Tensile Strength | 980 – 1150 MPa | 450 – 550 MPa |
| Yield Strength | 880 – 1020 MPa | 150 – 240 MPa |
| Elongation | 1 – 4% | 25 – 43% |
| Hardness | 280 – 320 HV | 110 – 130 HV |
Engineering and Processing Insights
- Stress Sensitivity:
Magnetic properties are highly sensitive to internal stress;bending or dropping the material post-anneal ruins its performance. - Heat Treatment:
Final annealing in hydrogen or vacuum at 1100°C–1200°C is required to achieve peak soft magnetic properties,reducing hardness and increasing permeability.
Our Advantages in Manufacturing 1J85 Strip
Precision Thickness Control
Our facility utilizes advanced cold-rolling mills equipped with automatic gauge control systems to achieve exceptionally tight thickness tolerances.This precise engineering ensures uniform material consistency across the entire length of the 1J85 strip,which is critical for stabilizing core loss and maintaining predictable magnetic performance in high-frequency applications.
Advanced Vacuum Melting
We employ state-of-the-art vacuum induction melting technologies to strictly minimize impurities such as carbon,sulfur,and oxygen in the chemical composition.This high-purity melting process guarantees an optimal grain matrix,resulting in superior initial magnetic permeability and low coercivity that consistently meets stringent international standards.
Specialized Heat Treatment
Our production line features specialized high-vacuum and pure hydrogen atmosphere annealing furnaces designed to eliminate internal stresses without introducing oxidation.This precisely controlled thermal processing ensures the 1J85 strip transitions perfectly to its high-permeability state,maximizing its ultimate soft magnetic shielding performance.
Strict Quality Assurance
Every batch of 1J85 strip undergoes rigorous non-destructive and magnetic performance testing using professional permeameters and metallographic analyzers.We maintain a comprehensive quality tracing system from raw materials to finished coils,ensuring excellent mechanical stability and flawless surface quality for our global clientele.
Microstructure and Crystallography
- Austenitic Lattice:
1J85 features a single-phase Austenitic matrix with a Face-Centered Cubic crystal structure.This highly symmetric lattice allows magnetic domains to rotate smoothly,yielding high permeability and exceptionally low coercivity. - Near-Zero Magnetostriction:
The specific 80% Ni and 5% Mo ratio targets the exact composition where both the magnetocrystalline anisotropy constant and the magnetostriction coefficient approach zero.This prevents the material from expanding or contracting when magnetized,minimizing internal friction during magnetic cycles.
Detailed Stamping & Fabrication Constraints
Fabrication must be carefully managed due to drastic property changes after heat treatment.
- Work-Hardening:
The material behaves like stainless steel in its cold-rolled state,requiring sharp carbide tools and proper technique to avoid rapid work-hardening,with fabrication completed before the final anneal. - Contamination:
Sulfur or chlorine-based cutting fluids must be avoided to prevent embrittlement during subsequent high-temperature annealing.
Alternating Current Limitations & Insulation
While excellent for DC applications,1J85 has limitations in high-frequency AC scenarios.
- Eddy Current Issues:
The material’s relatively low electrical resistivity (~0.56 to 0.60 μΩ · m) leads to significant eddy current losses and reduced permeability at high frequencies. - Insulation:
To mitigate these losses in AC cores,thin strips (0.05 mm to 0.1 mm) must be used,and each layer should be insulated,often using magnesium oxide (MgO) electrophoresis.
FAQs About 1J85 Strip
No.This is the most common mistake in manufacturing.Final hydrogen annealing removes internal stresses to unlock the alloy’s magnetic properties.Any mechanical force applied afterward—such as bending,stamping,cutting,or even dropping the part—reintroduces internal stresses.This structural strain severely degrades the magnetic permeability,forcing you to re-anneal the parts.
- Increases Electrical Resistivity:
It raises the material’s resistivity,which helps suppress eddy current losses in alternating current applications. - Simplifies Heat Treatment:
It lowers the critical cooling rate required to achieve the optimum atomic ordering state,making it much easier to obtain high permeability during industrial annealing.
1J85 has a relatively low electrical resistivity (~0.56 to 0.60 μΩ⋅m).In high-frequency AC fields,this low resistance allows strong eddy currents to form inside the material.These eddy currents generate heat and create opposing magnetic fields, causing the effective permeability to drop sharply.For high-frequency applications, extremely thin strips (e.g., 0.05 mm or less) must be used alongside surface insulation coatings.
Chemically,the high nickel content gives 1J85 decent atmospheric corrosion resistance,though it is not as rust-proof as stainless steel and should be protected from high humidity.Magnetically,its properties do not degrade over time unless it is subjected to mechanical shocks,strong physical vibrations,or temperatures exceeding its Curie Point (approx. 400°C),which would scramble its magnetic domain alignment.
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