1J77 Soft Magnetic Alloy Bar High Permeability Nickel Iron Round Rod
1J77 Soft Magnetic Alloy Bar is a high-nickel iron soft magnetic alloy containing controlled additions of molybdenum and copper. It is commonly identified as Ni77Mo4Cu5 Bar, Ni77Cu5Mo4 Bar, high permeability nickel iron alloy bar, Permalloy bar and precision soft magnetic alloy rod. The alloy is designed to provide high magnetic permeability, low coercivity, low magnetic loss and effective response in weak magnetic fields.
Product Parameters
| Item | Product Details |
|---|---|
| Product Name | 1J77 Soft Magnetic Alloy Bar / High Permeability Nickel Iron Round Rod |
| Grade | 1J77 / Ni77Mo4Cu5 / Ni77Cu5Mo4 |
| Material Family | High-nickel soft magnetic precision alloy |
| Available Shapes | Round bar, rod, forged bar, flat bar, strip, sheet, wire and machined components |
| Round Bar Diameter | Approximately 3 mm to 300 mm; customized forged dimensions available |
| Length | 1000 mm to 6000 mm or customized cut-to-length |
| Surface Finish | Black, bright, peeled, turned, polished, centerless ground or machined |
| Delivery Condition | Hot rolled, forged, cold drawn, annealed, stress relieved or customer specified |
| Reference Standards | GB/T 32286.1, GB/T 15018 or customer-approved technical specification |
| Tolerance | Commercial tolerance, h9, h11, ground tolerance or drawing-specific tolerance |
| Key Magnetic Features | High permeability, low coercivity and low magnetic loss |
| Certificates | MTC, EN 10204 3.1, PMI report, dimensional report and magnetic test report |
Chemical Composition
The chemical composition of 1J77 is carefully controlled to obtain high permeability and low coercivity after the appropriate magnetic annealing process. Nickel forms the main alloying element, while molybdenum and copper help improve magnetic performance and electrical resistivity. The following data is a typical reference and final chemistry should be confirmed by the applicable specification and Mill Test Certificate.
| Element | Typical Content (%) | Technical Function |
|---|---|---|
| Nickel (Ni) | 75.5–78.0 | Provides high magnetic permeability and soft magnetic behavior |
| Copper (Cu) | 4.8–6.0 | Supports controlled magnetic structure and processing response |
| Molybdenum (Mo) | 3.9–4.5 | Improves permeability, electrical resistivity and magnetic stability |
| Iron (Fe) | Balance | Forms the base of the nickel-iron soft magnetic alloy |
| Manganese (Mn) | 0.30–0.60 | Supports melting control and hot-working performance |
| Silicon (Si) | 0.15–0.30 | Controlled residual affecting magnetic and processing properties |
| Carbon (C) | ≤ 0.03 | Restricted to reduce magnetic aging and maintain ductility |
| Phosphorus (P) | ≤ 0.020 | Controlled impurity for cleanliness and mechanical reliability |
| Sulfur (S) | ≤ 0.020 | Controlled impurity for forming and magnetic performance |
Mechanical Properties
Mechanical properties of 1J77 soft magnetic alloy bar vary significantly with cold-working ratio, bar diameter, annealing temperature and final magnetic heat treatment. Soft annealed material provides improved ductility, while cold-worked material provides higher strength but may require final annealing to restore magnetic permeability.
| Property | Typical Reference | Engineering Meaning |
|---|---|---|
| Tensile Strength, Annealed | Approximately 540 MPa | Reference for soft and magnetically annealed material |
| Tensile Strength, Cold Worked | Up to approximately 980 MPa | Higher strength before final magnetic annealing |
| Elongation, Annealed | Approximately 40% | Supports forming and machining in soft condition |
| Elongation, Cold Worked | Approximately 2% or condition dependent | Indicates reduced ductility after heavy cold work |
| Density | Approximately 8.6 g/cm³ | Used for weight, machining and logistics calculations |
| Electrical Resistivity at 20°C | Approximately 0.55 Ω·mm²/m | Helps reduce eddy-current loss in magnetic components |
| Curie Temperature | Approximately 350°C | Magnetic properties decline significantly near this region |
| Magnetic Performance | High permeability and low coercivity | Suitable for weak-field magnetic circuits and shielding |
Common Size Table
| Diameter | Typical Length | Common Finish | Typical Use |
|---|---|---|---|
| 3–10 mm | 1000–3000 mm | Bright, cold drawn or ground | Relay pins, magnetic cores and sensor components |
| 12–30 mm | 2000–6000 mm | Bright, peeled, polished or ground | Solenoid cores, armatures and magnetic pole parts |
| 32–80 mm | 2000–6000 mm | Black, peeled or rough turned | Transformer parts, magnetic housings and machined cores |
| 85–150 mm | Cut-to-length | Forged, turned or rough machined | Large magnetic poles and precision instrument components |
| Above 150 mm | Customized | Forged and rough machined | Project-specific magnetic forgings and large components |
Different Specifications Comparison
| Product Form | Main Feature | Recommended Application | Selection Advice |
|---|---|---|---|
| 1J77 Round Bar | Standard solid stock for machining | Magnetic cores, poles, rods and armatures | Recommended for CNC-machined magnetic parts |
| 1J77 Forged Bar | Suitable for large cross-sections | Large magnetic poles, rings and custom parts | Choose when rolled stock dimensions are insufficient |
| 1J77 Bright Bar | Improved surface and dimensional accuracy | Precision relay, sensor and instrument parts | Suitable for automatic machining and visible surfaces |
| 1J77 Ground Bar | Tight tolerance and smooth surface | Precision shafts, magnetic plungers and cores | Recommended for close-tolerance components |
| 1J77 Sheet or Strip | Thin section reduces eddy-current loss | Magnetic shielding and laminated cores | Preferred for alternating-current magnetic circuits |
| 1J77 Wire | Small section for wound or formed components | Magnetic sensors, coils and miniature components | Choose according to diameter and final annealing process |
Comparison with Other Soft Magnetic Alloys
| Grade | Nominal Alloy Type | Main Characteristic | Typical Application |
|---|---|---|---|
| 1J46 | Medium nickel-iron alloy | Moderate permeability and higher saturation | Relays, transformers and magnetic components |
| 1J50 | FeNi50 soft magnetic alloy | Balanced permeability and saturation induction | Transformers, chokes and electromagnetic components |
| 1J77 | Ni77Mo4Cu5 alloy | High permeability and low coercivity | Weak-field cores, shielding and precision instruments |
| 1J79 | High-nickel molybdenum alloy | Very high permeability after proper annealing | Magnetic shielding and sensitive transformer cores |
| 1J85 | High-permeability nickel alloy | Extremely sensitive weak-field response | Precision shielding, amplifiers and measuring devices |
Equivalent Standards and International Names
| Naming System | Designation or Reference | Remarks |
|---|---|---|
| Chinese Grade | 1J77 | High-permeability nickel-iron soft magnetic alloy |
| Chemical Description | Ni77Mo4Cu5 / Ni77Cu5Mo4 | Nominal nickel-molybdenum-copper composition |
| Common Alloy Family | Permalloy Type | Commercial soft magnetic nickel-iron alloy family |
| Common Cross-Reference | Permalloy C Type | Property and composition comparison is required |
| Russian Reference | 77НХЛ / 77NKhL Type | Regional reference requiring specification confirmation |
| Chinese Standard | GB/T 32286.1 | Soft magnetic alloys, nickel-iron alloy series |
| Earlier Chinese Reference | GB/T 15018 | Common precision alloy specification reference |
Production Process Flow
| Step | Production Process | Quality Control Focus |
|---|---|---|
| 1 | Raw Material Selection | Confirm nickel, iron, molybdenum and copper purity |
| 2 | Vacuum Melting | Control composition, gas content and impurity levels |
| 3 | Ingot Casting | Manage segregation, shrinkage and internal quality |
| 4 | Homogenization | Improve chemical and microstructural uniformity |
| 5 | Hot Forging or Rolling | Control working temperature, reduction and grain structure |
| 6 | Intermediate Annealing | Restore ductility for further processing |
| 7 | Cold Drawing and Straightening | Improve dimensional accuracy and surface quality |
| 8 | Peeling, Turning or Grinding | Achieve specified diameter and tolerance |
| 9 | Final Magnetic Annealing | Reduce residual stress and develop permeability |
| 10 | Inspection and Export Packing | Verify grade, dimensions, magnetic properties and traceability |
Product Inspection
| Inspection Item | Inspection Method | Purpose |
|---|---|---|
| Chemical Composition | Spectrometer or laboratory chemical analysis | Confirm Ni, Mo and Cu content and grade compliance |
| PMI Testing | Positive Material Identification | Reduce material mix-up and substitution risk |
| Magnetic Permeability Test | Initial and maximum permeability testing | Confirm weak-field magnetic response |
| Coercivity Test | Magnetic hysteresis measurement | Verify soft magnetic and low-loss performance |
| Saturation Induction Test | Magnetic property testing | Support magnetic circuit design and material approval |
| Mechanical Testing | Tensile, elongation and hardness testing | Verify delivery and processing condition |
| Dimensional Inspection | Caliper, micrometer and straightness measurement | Confirm diameter, length and tolerance |
| Ultrasonic Testing | UT when technically applicable | Evaluate internal soundness of large bars and forgings |
| Third-Party Inspection | SGS, BV, TÜV or customer-appointed agency | Provide independent verification before shipment |
Product Packaging
| Packaging Item | Packaging Method | Purpose |
|---|---|---|
| Surface Protection | Anti-rust oil, VCI paper, plastic film or protective wrapping | Reduce oxidation, moisture and surface damage |
| Individual Separation | Paper, foam or plastic separation for finished bars | Prevent scratches and mechanical impact |
| Bundle Packing | Bars secured with protected straps | Prevent movement and bending during handling |
| End Protection | Plastic caps, foam or wooden end blocks | Protect precision-machined ends |
| Wooden Case or Pallet | Export-standard reinforced wooden packing | Support sea, air and road transportation |
| Product Marking | Grade, size, heat number and quantity | Maintain product identification and traceability |
Applications & Machinability
Industrial Applications
| Industry | Typical Components | Why 1J77 Is Used |
|---|---|---|
| Medical Instruments | Magnetic sensors, shielding parts and precision electromagnetic components | High permeability supports sensitive signal and shielding applications |
| Aerospace | Relays, transformers, sensors and magnetic shielding components | Low coercivity supports efficient response in precision electronics |
| Marine Hardware | Sealed sensors, navigation electronics and magnetic shielding parts | Useful for magnetic control, although corrosion protection is required |
| Chemical Processing | Instrument sensors, control relays and shielded measurement components | Supports sensitive instrumentation when chemical exposure is controlled |
| Electrical and Electronics | Transformer cores, chokes, relays, solenoids and recording heads | High permeability and low coercivity reduce magnetic losses |
| Magnetic Shielding | Shielding enclosures, sleeves, housings and precision covers | Redirects weak magnetic fields around sensitive equipment |
| Precision Instruments | Measuring devices, magnetic amplifiers and control components | Provides stable response in weak-field magnetic circuits |
Machinability, Welding and Heat Treatment
| Processing Property | Performance | Recommendation |
|---|---|---|
| Machinability | Moderate and not as free-cutting as 303 stainless steel | Use rigid machines, sharp tools, controlled feeds and adequate coolant |
| Cold Forming | Good in annealed condition but work-hardens during deformation | Use intermediate annealing for substantial cold reduction |
| Hot Working | Suitable for controlled forging and rolling | Control temperature to avoid surface and grain defects |
| Welding Performance | Weldable using a qualified nickel-alloy procedure | Final magnetic annealing may be needed after welding |
| Magnetic Annealing | Essential for developing high permeability and low coercivity | Use controlled atmosphere or vacuum and qualified cooling conditions |
| Heat Treatment | Suitable for annealing and stress relief, not precipitation hardening | Complete machining and forming before final magnetic annealing |
| Residual Stress Sensitivity | Magnetic performance can decline after machining or deformation | Avoid mechanical damage after final annealing |
| Corrosion Resistance | Moderate and lower than corrosion-resistant stainless steel | Use coating, plating or dry protection in aggressive environments |
Why Choose SAKY STEEL?
| Supplier Advantage | Customer Value |
|---|---|
| Soft Magnetic Alloy Experience | Supply support for 1J77, 1J79, 1J85, 1J50 and other precision magnetic alloys. |
| Customized Dimensions | Diameter, length, machining allowance, surface finish and tolerance can be customized. |
| Heat Number Control | Material markings and inspection documents can be linked to the original production heat. |
| Certificate Support | We can provide MTC (Mill Test Certificate / 质保书) and EN 10204 3.1 certificate according to order requirements. |
| Magnetic Testing Support | Permeability, coercivity, saturation induction and electrical resistivity testing can be discussed. |
| Anti-Fake Material Control | Chemical analysis, PMI, heat-number review and document checks reduce substitution risk. |
| Third-Party Inspection | SGS, BV, TÜV or customer-appointed inspection can be arranged. |
| Export Packaging Experience | Protective wrapping, wooden cases, pallets and custom shipping marks are available. |
FAQ
What is 1J77 Soft Magnetic Alloy Bar?
1J77 Soft Magnetic Alloy Bar is a high-nickel iron alloy containing molybdenum and copper. It is designed for high magnetic permeability, low coercivity and efficient response in weak magnetic fields.
What is the chemical composition of 1J77?
Typical 1J77 contains approximately 75.5% to 78.0% nickel, 4.8% to 6.0% copper and 3.9% to 4.5% molybdenum, with iron as the balance. Final values should be verified by the applicable standard and MTC.
What is 1J77 alloy used for?
1J77 is used for transformer cores, magnetic shielding, relays, solenoids, sensors, magnetic amplifiers, recording heads, precision measuring instruments and weak-field electromagnetic components.
Is 1J77 a Permalloy grade?
1J77 belongs to the high-nickel Permalloy-type soft magnetic alloy family. Commercial names should not be treated as exact equivalents without comparing composition, magnetic properties and heat-treatment requirements.
Why does 1J77 require magnetic annealing?
Machining, cold forming and welding introduce residual stress that can reduce permeability and increase coercivity. A qualified final annealing cycle helps relieve stress and develop the required soft magnetic structure.
Is 1J77 easy to machine?
1J77 has moderate machinability but is not a free-cutting material like 303 stainless steel. Rigid equipment, sharp cutting tools, controlled feeds and sufficient coolant are recommended.
Can 1J77 be welded?
1J77 can be welded using a qualified nickel-alloy procedure. Final magnetic annealing may be necessary because welding stress and heat-affected zones can change the magnetic performance.
Is 1J77 suitable for heat treatment?
Yes. Annealing and stress relief are essential processing steps for 1J77. It is not a precipitation-hardening alloy, and the main purpose of heat treatment is to restore ductility and optimize magnetic properties.
Can SAKY STEEL provide magnetic test reports?
Magnetic permeability, coercivity, saturation induction and other magnetic tests can be discussed according to the product form, specimen dimensions, heat-treatment condition and purchase specification.
Can 1J77 Bar be supplied with MTC?
Yes. SAKY STEEL can provide MTC, EN 10204 3.1 certificate, chemical analysis, PMI report, dimensional inspection report and other quality documents according to the order.
Is 1J77 corrosion resistant?
1J77 has moderate atmospheric corrosion resistance but is not equivalent to corrosion-resistant stainless steel. Protective oil, plating, coating or controlled storage may be needed in humid, marine or chemical environments.
What information is required for a quotation?
Please provide grade, standard, diameter, length, quantity, surface finish, tolerance, delivery condition, magnetic property requirements, heat-treatment condition, inspection documents, packaging requirements and delivery destination.
