MG Carbon Brush
MG Carbon Brush is a metal-graphite brush material in which graphite is blended or impregnated with copper or silver powder, classified as MG under JIS C2802 and in the J-type series of GB/T 1416; grades run MG-LC, MG-MC and MG-HC by metal content, plus MG-Ag and MG-SnPb variants.
Reference datasheet — MG Carbon Brush is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the MG-MC condition
MG Carbon Brush tempers and conditions
MG Carbon Brush is supplied in 5 conditions, soft to hard. MG-MC is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Copper graphite with tin/lead lubricating additions | Specify tin/lead lubricating additions when high surface speeds or dry, high-altitude air demand extra lubrication and lower ring loss; lead-bearing versions are largely replaced under RoHS. | 17 | 0.5 | 10 HV | 100 W/m·K | |
MG-MCDefault Medium-copper metal graphite | Default general-purpose ~55–75 % Cu metal-graphite grade: use for low-voltage, high-current DC motors, starters and traction motors where resistivity and wear resistance must be balanced. | 12 HV | 110 W/m·K | |||
Low-copper metal graphite | Pick for 24–110 V DC motors with demanding commutation, where the higher contact voltage drop of the 30–50 % copper content suppresses ring fire; conductivity is lower than richer copper grades. | 15 HV | 55 W/m·K | |||
Silver-graphite brush / contact grade | Use the silver-graphite grade for instruments, servo tachogenerators, fractional-horsepower motors and signal slip rings needing very low, oxidation-free contact drop; it is the costliest option. | 18 HV | 190 W/m·K | |||
High-copper metal graphite | Choose ~80–90 % copper content for plating and electrolysis rectifier sets, slip rings and ultra-low-voltage, very high current duty where minimum contact drop matters; wear life is shorter. | 20 HV | 200 W/m·K |
What is MG Carbon Brush?
MG Carbon Brush is a metal-graphite brush material in which graphite is blended or impregnated with copper or silver powder, classified as MG under JIS C2802 and in the J-type series of GB/T 1416; grades run MG-LC, MG-MC and MG-HC by metal content, plus MG-Ag and MG-SnPb variants. The high metal content gives low contact voltage drop and about 110 W/m·K conductivity for low-voltage, high-current machines, supplied as pressed and machined brush blocks. Service temperature is limited to 200 °C and the copper phase tarnishes and oxidises in humid or contaminated air. Use EG electrographite where higher resistance and better commutation are needed. MG Carbon Brush has a density of 3.6 g/cm³ (0.13 lb/in³), lighter than 64% of ceramic grades. It melts at 1,083°C (1,981 °F). MG Carbon Brush has a tensile strength of 20 MPa (2.9 ksi), weaker than 88% of ceramic grades. The elastic modulus is 13 GPa (1.89 Msi).
What is MG Carbon Brush used for?
- automotive starter motors
- low-voltage DC motors
- slip rings for high-current transfer
Advantages
- Easy to machine — 85/100, better than 91% of ceramic grades
- Conducts heat well — 110 W/m·K (63.6 BTU/hr·ft·°F), better than 86% of ceramic grades
- Low embodied carbon — 4.5 kg CO₂/kg, better than 78% of ceramic grades
Limitations
- Hard to polish — 35/100, worse than 93% of ceramic grades
- Low stiffness — 13 GPa (1.89 Msi), worse than 88% of ceramic grades
- Limited service temperature — 200°C (392 °F), worse than 84% of ceramic grades
- Needs corrosion protection — 50/100, worse than 83% of ceramic grades
MG Carbon Brush properties
Typical room-temperature values for MG Carbon Brush-MG-MC; bars are the position among ceramic grades.
Physical3
MG Carbon Brush has a density of 3.6 g/cm³ (0.13 lb/in³), lighter than 64% of ceramic grades. It melts at 1,083°C (1,981 °F).
Mechanical8
MG Carbon Brush has a tensile strength of 20 MPa (2.9 ksi), weaker than 88% of ceramic grades. The elastic modulus is 13 GPa (1.89 Msi).
Thermal5
MG Carbon Brush is rated for continuous service to 200°C (392 °F). It conducts heat at 110 W/m·K (63.6 BTU/hr·ft·°F), better than 86% of ceramic grades. Thermal expansion is 10 µm/m·K (5.56 µin/in·°F).
Electrical2
MG Carbon Brush has an electrical resistivity of 5×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is fair (50/100), worse than 83% of ceramic grades.
Sustainability4
Producing a kilogram of MG Carbon Brush takes about 55 MJ of energy and emits 4.5 kg of CO₂ — less than 78% of ceramic grades. Typical recycled content is 25%.
Manufacturability3
MG Carbon Brush's machinability is excellent (85/100, better than 91% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the ceramic family
Yield strength against density for every ceramic grade FabDigit runs. MG Carbon Brush is highlighted; hover a dot for its name, or open the interactive family chart.
Working with MG Carbon Brush
Is MG Carbon Brush easy to machine?
Cut dry with carbide or PCD tooling at high speed and low feed; explosion-protected dust extraction is required because the copper-bearing dust is electrically conductive and can short electrical equipment.
Can MG Carbon Brush be welded?
Not weldable; lead wires are fixed to the brush body by copper-tamped riveting or cast-in connections, or by ultrasonic crimping.
Can MG Carbon Brush be formed, bent or molded?
Powder-metallurgy route: copper and graphite powders are blended, die pressed at 100–400 MPa, sintered at 700–1000 °C in a reducing or inert atmosphere, re-pressed for sizing, then machined and chamfered.
MG Carbon Brush chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cuelectrolytic Cu powder; to 90% in high-Cu; Ag-graphite uses Ag | 30 – 90 | 68 |
| Snadded in some grades to improve lubrication and sintering | 0 – 5 | 0 |
| Pbtraditional self-lubricating grades; absent in RoHS grades | 0 – 8 | 0 |
| C (graphite)natural flake or synthetic graphite; minor pitch/resin residual carbon | balance |
What surface finishes work on MG Carbon Brush?
End and curved faces are ground to the commutator radius (arc fitting); impregnation or copper plating may be applied to lower contact resistance. No painting is used.
How much does MG Carbon Brush cost?
MG Carbon Brush is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
MG Carbon Brush — frequently asked
What is MG Carbon Brush used for?
MG Carbon Brush is typically used for automotive starter motors, low-voltage DC motors and slip rings for high-current transfer. In short: lowest-resistance brush grade; for low-voltage high current; 200 °C service ceiling.
What is the tensile strength of MG Carbon Brush?
MG Carbon Brush has a typical tensile strength of 20 MPa (2.9 ksi) — weaker than 88% of ceramic grades. Strength varies by condition: see the 5 listed tempers.
Is MG Carbon Brush easy to machine?
Yes — machinability is rated excellent (85/100, better than 91% of ceramic grades). Cut dry with carbide or PCD tooling at high speed and low feed; explosion-protected dust extraction is required because the copper-bearing dust is electrically conductive and can short electrical equipment.
Can MG Carbon Brush be welded?
Not weldable; lead wires are fixed to the brush body by copper-tamped riveting or cast-in connections, or by ultrasonic crimping.
What surface finishes work on MG Carbon Brush?
End and curved faces are ground to the commutator radius (arc fitting); impregnation or copper plating may be applied to lower contact resistance. No painting is used.
Can MG Carbon Brush be formed, bent or molded?
Powder-metallurgy route: copper and graphite powders are blended, die pressed at 100–400 MPa, sintered at 700–1000 °C in a reducing or inert atmosphere, re-pressed for sizing, then machined and chamfered.
What is the maximum service temperature of MG Carbon Brush?
MG Carbon Brush is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does MG Carbon Brush cost?
MG Carbon Brush is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- JIS C 2802 Carbon brushes for electrical machines — JSA (2016)
- GB/T 1416 (Carbon brushes) — SAC (2019)
- IEC 60136 Dimensions of brushes and brush-holders for electrical machinery — IEC (1986)
- Metal-graphite and silver-graphite brush grade data — Morgan Advanced Materials / Schunk / Mersen (2023)
- ASM Handbook Vol.2 — Properties of Copper–Graphite Composites — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.