6J21 Precision Resistance Alloy Bar
6J21 Precision Resistance Alloy Bar is a nickel-chromium based precision resistance alloy bar designed for stable resistance performance, controlled resistance temperature coefficient, good oxidation resistance and reliable electrical behavior. It is used in precision resistors, electrical instruments, measuring devices, heating control parts, electronic assemblies and industrial control equipment.
SASA ALLOY supplies 6J21 bars, 6J21 rods, 6J21 resistance alloy bar stock and cut-to-length resistance alloy materials in customized diameter, length, tolerance and surface finish. MTC (Mill Test Certificate), EN 10204 3.1 certificate, PMI inspection, dimensional inspection, electrical property testing and third-party inspection can be provided according to project requirements.
Product Parameters
| Item | Details |
|---|---|
| Product Name | 6J21 Precision Resistance Alloy Bar / 6J21 Resistance Alloy Rod |
| Grade | 6J21 |
| Material Type | Nickel-Chromium based precision resistance alloy |
| Shape & Sizes | Round bar, rod, cut bar, machined bar; common diameter 3 mm – 100 mm, customized size available |
| Length | 1000 mm – 6000 mm, cut-to-length available according to customer drawing |
| Surface Finish | Black, bright, peeled, turned, polished, ground |
| Standards | GB/T 15002, GB/T 15001, GB/T 1234 or customer technical specification |
| Tolerance | Standard tolerance, h9, h11, k12 or customized tolerance according to drawing |
| Certificate | MTC, EN 10204 3.1 certificate, PMI report, dimensional inspection report, electrical property report and third-party inspection available |
Chemical Composition
The following chemical composition is a typical reference for 6J21 nickel-chromium precision resistance alloy. Since 6J21 may be supplied according to different customer specifications, the final chemical values should be confirmed according to the actual Mill Test Certificate.
| Element | Typical Content | Function in Alloy |
|---|---|---|
| Nickel (Ni) | Balance | Provides stable electrical resistance and oxidation resistance |
| Chromium (Cr) | Approx. 19.0 – 23.0% | Improves oxidation resistance and high-temperature stability |
| Iron (Fe) | Controlled | Supports alloy structure and processing behavior |
| Silicon (Si) | Controlled | Supports oxidation resistance and electrical stability |
| Manganese (Mn) | Controlled | Controlled residual element for processing stability |
| Carbon (C) | Low / Controlled | Controlled impurity for electrical and mechanical reliability |
| Phosphorus (P) | Controlled | Controlled impurity for clean structure |
| Sulfur (S) | Controlled | Controlled impurity for processing quality |
Mechanical Properties
6J21 is mainly selected for precision resistance performance and stable electrical properties. Mechanical properties may vary depending on bar diameter, hot working, cold working, annealing and final processing condition.
| Property | Reference Value | Engineering Meaning |
|---|---|---|
| Material Type | Precision resistance alloy | Designed for resistor, instrument and electrical control applications |
| Electrical Resistivity | Specification dependent | Core property for precision resistance components |
| Resistance Temperature Coefficient | Specification dependent | Important for stable resistance over temperature changes |
| Tensile Strength | Condition dependent | Depends on bar size, cold working and heat treatment condition |
| Hardness | Condition dependent | Can be adjusted by processing condition |
| Oxidation Resistance | Good for Ni-Cr alloy system | Useful for electrical and heating-related resistance parts |
| Dimensional Stability | Good after proper processing | Important for precision instruments and control components |
Common Size Table
| Diameter | Typical Length | Surface Finish | Common Use |
|---|---|---|---|
| 3 – 8 mm | 1000 – 3000 mm | Bright, polished, ground | Small resistor parts, electrical pins, instrument components |
| 10 – 25 mm | 2000 – 6000 mm | Peeled, turned, bright | Precision resistance parts, electrical assemblies, control elements |
| 26 – 50 mm | 3000 – 6000 mm | Black, peeled, rough turned | Machined resistance components, industrial electrical parts |
| 55 – 100 mm | Cut-to-length | Forged, rough turned, machined | Custom electrical components and project-specific parts |
| Wire / Strip Form | Customized | Bright, annealed, cold drawn | Precision resistors, heating elements, shunts and electronic parts |
Different Specifications Comparison
| Product Form | Main Feature | Recommended Application | Selection Advice |
|---|---|---|---|
| 6J21 Round Bar | Good machining allowance and stable resistance alloy base | Precision electrical components, resistor parts, instrument parts | Recommended for machined resistance alloy components |
| 6J21 Rod | Smaller diameter and easier processing | Electrical pins, control parts, small machined components | Recommended for small precision parts |
| 6J21 Bright Bar | Better surface finish and dimensional control | Electronic instruments, precision devices and visible parts | Recommended when surface quality is important |
| 6J21 Wire | Suitable for resistance wire and winding components | Precision resistors, heating elements, electrical coils | Recommended when wire geometry is required |
| 6J21 Strip / Sheet | Suitable for stamped electrical resistance parts | Shunts, resistor sheets, control assemblies | Recommended for flat resistance components |
Equivalent Standards and International Names
| Standard / Name | Designation | Remarks |
|---|---|---|
| Chinese Grade | 6J21 | Precision resistance alloy grade |
| Alloy Family | 6J Series Resistance Alloy | Precision alloy series for resistance and electrical applications |
| Chemical Type | Ni-Cr based resistance alloy | Nickel-chromium resistance alloy system |
| Related Grades | 6J15 / 6J20 / 6J22 / 6J40 | Selected according to resistivity, temperature coefficient and application |
| Chinese Standard | GB/T 15002 / GB/T 15001 / GB/T 1234 | Technical reference for precision alloy and resistance alloy products |
| Common Product Forms | Bar, rod, wire, strip, sheet, plate | Different forms for electrical resistance and precision components |
Production Process Flow
| Step | Process | Quality Control Focus |
|---|---|---|
| 1 | Raw Material Selection | Check nickel, chromium and alloy element control, raw material source and heat number traceability |
| 2 | Melting / Refining | Control chemical composition, inclusion level and impurity elements |
| 3 | Ingot / Billet Preparation | Ensure suitable billet quality for rolling, forging or drawing |
| 4 | Hot Rolling / Forging | Control bar size, internal structure and deformation process |
| 5 | Annealing | Improve processability and stabilize electrical properties |
| 6 | Cold Working / Straightening | Adjust dimensional accuracy and mechanical condition |
| 7 | Peeling / Turning / Grinding | Improve surface quality and dimensional tolerance |
| 8 | Electrical Property Testing | Check resistivity, resistance temperature coefficient or customer-defined electrical requirements |
| 9 | Inspection and Testing | PMI, chemical analysis, dimensional inspection, surface inspection and mechanical test if required |
| 10 | Packaging and Shipment | Protective wrapping, wooden case, label, heat number and shipping mark |
Product Inspection
| Inspection Item | Inspection Method | Purpose |
|---|---|---|
| Chemical Composition | Spectrometer analysis / laboratory test | Confirm 6J21 precision resistance alloy grade and element control |
| PMI Test | Positive Material Identification | Prevent material mix-up and wrong grade shipment |
| Electrical Property Test | Resistivity and resistance temperature coefficient test if required | Verify electrical performance for resistor and instrument applications |
| Mechanical Test | Tensile strength, hardness or other required test | Verify mechanical performance according to order requirement |
| Dimension Inspection | Caliper, micrometer, straightness inspection | Confirm diameter, length, tolerance and straightness |
| Surface Inspection | Visual inspection and surface quality check | Check cracks, scratches, oxidation, peeling defects and surface finish |
| Ultrasonic Testing | UT inspection if required | Check internal defects for critical bars and forged sections |
| Certificate | MTC / EN 10204 3.1 / inspection report | Ensure material traceability and project documentation |
Product Packaging
| Packaging Item | Details | Benefit |
|---|---|---|
| Surface Protection | Plastic film, anti-rust paper, oil protection or protective wrapping | Protects bar surface from scratches and oxidation during transportation |
| Bundle Packing | Bars bundled with steel strips or protective belts | Prevents movement, bending and collision |
| Wooden Case / Wooden Pallet | Export-standard wooden case or pallet | Suitable for long-distance sea, air and truck shipment |
| Labeling | Grade, size, heat number, quantity, net weight and customer mark | Improves material traceability after delivery |
| Document Support | Packing list, invoice, MTC, EN 10204 3.1 certificate and inspection report if required | Supports customs clearance and project acceptance |
Applications & Machinability
Applications
| Industry | Typical Parts | Why 6J21 Bar Is Used |
|---|---|---|
| Medical Instruments | Electrical control parts, instrument components, precision device parts | Stable resistance performance can support precision electrical functions in instrument assemblies |
| Aerospace | Electrical measuring parts, control elements, precision resistance components | Stable electrical behavior and dimensional reliability support precision control systems |
| Marine Hardware | Electrical control components, resistor parts and sensor assemblies | Used for electrical resistance function parts; surface and environmental protection should be considered |
| Chemical Processing | Instrument electrical parts, control device parts and resistance components | Suitable for electrical function parts; corrosion environment should be evaluated before material selection |
| Electrical & Electronics | Precision resistors, heating elements, shunts, control parts and electronic assemblies | Precision resistance alloy supports stable resistance and reliable electrical performance |
Machinability, Welding and Heat Treatment
| Processing Property | Performance | Recommendation |
|---|---|---|
| Machinability | Machinable, but not a free-cutting alloy like 303 stainless steel | Use rigid machines, sharp carbide tools, suitable cutting speed and sufficient coolant |
| Forming Performance | Can be processed into bar, rod, wire, strip and electrical components under proper condition | Choose annealed or cold worked condition according to final product form |
| Welding Performance | Welding or joining may be possible, but electrical resistance and heat-affected zone should be considered | Confirm welding or joining procedure and final electrical property requirements before fabrication |
| Heat Treatment | Annealing may be used to adjust processing condition and stabilize properties | Final heat treatment should follow electrical performance target and project specification |
| Cold Working | Cold working can affect mechanical properties and dimensional accuracy | Electrical properties should be checked after final processing if required |
| Surface Protection | Surface oxidation may occur during storage and transportation | Use oil protection, dry storage and export protective packaging |
Why Choose SAKY STEEL?
| Advantage | Description |
|---|---|
| Professional Precision Alloy Supply | SAKY STEEL supplies precision alloys including 6J21, 6J15, 6J20, 6J40, 1J soft magnetic alloys, 2J permanent magnetic alloys, 3J elastic alloys and 4J expansion alloys for industrial and high-performance applications. |
| Customized Size Capability | Diameter, length, surface finish, tolerance, cutting service and machining allowance can be customized according to customer drawings or project requirements. |
| Quality Control and Traceability | Material traceability, heat number control, PMI testing, dimensional inspection, surface inspection, mechanical testing and electrical property testing can be arranged. |
| Certificate Support | We can provide MTC (Mill Test Certificate / 质保书), EN 10204 3.1 certificate, PMI report, inspection report and other quality documents according to order requirements. |
| Export Packaging Experience | Export wooden cases, wooden pallets, protective wrapping, oil protection and clear labels help ensure safe delivery for international shipments. |
| Technical Service Support | Our team can support grade selection, equivalent standard checking, electrical property requirement confirmation and technical document preparation before shipment. |
FAQ
Q1: What is 6J21?
6J21 is a precision resistance alloy grade, generally used for resistance elements, electrical instruments, measuring devices, control components and precision electrical assemblies. Final composition and electrical properties should be confirmed by MTC and customer specification.
Q2: What is 6J21 Bar used for?
6J21 Bar is used for machined resistance alloy parts, resistor components, electrical control elements, instrument parts, electronic assemblies and industrial precision components.
Q3: Which product category should 6J21 be placed in?
6J21 should be placed under Precision Alloy. If the website has a Resistance Alloy subcategory, it should be placed under Precision Alloy > Resistance Alloy.
Q4: Can SASA ALLOY provide 6J21 with MTC?
Yes. SASA ALLOY can provide MTC (Mill Test Certificate / 质保书), EN 10204 3.1 certificate, PMI report, dimensional inspection report, electrical property report and third-party inspection documents according to customer requirements.
Q5: What sizes of 6J21 Bar are available?
Common diameters include 3 mm to 100 mm. Length, tolerance and surface finish can be customized. Cut-to-length service is available for precision machining and electrical component production.
Q6: Is 6J21 easy to machine?
6J21 is machinable, but it is not a free-cutting alloy like 303 stainless steel. Rigid equipment, sharp carbide tools, suitable cutting speed and sufficient coolant are recommended.
Q7: Can 6J21 be welded?
Welding or joining may be possible, but the effect on electrical resistance and the heat-affected zone should be considered. For precision resistance parts, the final electrical properties should be checked after fabrication.
Q8: Does 6J21 require heat treatment?
Annealing or stress relief may be used to adjust processing condition and stabilize electrical properties. Final heat treatment should follow project specifications and required electrical performance.
Q9: What should be confirmed before ordering 6J21?
Customers should confirm grade, product form, diameter, length, quantity, surface finish, tolerance, resistivity, resistance temperature coefficient, heat treatment condition and certificate requirements before ordering.
Q10: How can I get a quotation for 6J21?
Please send your required grade, diameter, length, quantity, surface finish, tolerance, electrical property requirement and certificate requirements to SASA ALLOY. Our team will check availability, production route, delivery time and price for your project.
