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Stainless Steel CB7Cu-2 vs CD4MCuN

Stainless Steel · grade comparison

Stainless Steel CB7Cu-2 and CD4MCuN are both stainless steel grades. CB7Cu-2 is the stronger of the two: yield strength 860 MPa (125 ksi) against 550 MPa (79.8 ksi) for CD4MCuN, about 56% more; tensile strength follows at 1,000 MPa (145 ksi) vs 730 MPa (106 ksi). In exchange, CD4MCuN is the more ductile: elongation 25% versus 13% for CB7Cu-2, and CB7Cu-2 is harder (311 HB vs 250 HB). CB7Cu-2 conducts heat better (17.8 W/m·K vs 16 W/m·K). On the shop floor, CB7Cu-2 machines more easily (fair vs poor) and CB7Cu-2 welds better (65 vs 55 out of 100).

CB7Cu-2Choose it when strength drives the design, or when the part is machined in volume.

CD4MCuNChoose it when the part is bent, formed or impact-loaded.

CB7Cu-2 vs CD4MCuN: properties

CB7Cu-2CD4MCuN

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

196 GPa28.4 Msi
200 GPa29 Msi

Bulk Modulus

152 GPa22 Msi
145 GPa21 Msi

Poisson's Ratio

0.28
0.3

Tensile Strength (Ultimate)

1,000 MPa145 ksi
730 MPa106 ksi

Yield Strength (0.2% offset)

860 MPa125 ksi
550 MPa79.8 ksi

Elongation at Break

13%
25%

Compressive Strength

880 MPa128 ksi
560 MPa81.2 ksi

Shear Strength

640 MPa92.8 ksi
450 MPa65.3 ksi

Fatigue Strength (Endurance Limit)

460 MPa66.7 ksi
300 MPa43.5 ksi

Fracture Toughness (K_IC)

105 MPa·√m95.6 ksi·√in
90 MPa·√m81.9 ksi·√in

Charpy V-Notch Impact (RT)

47 J34.7 ft·lbf
70 J51.6 ft·lbf

Hardness, Brinell

311 HB
250 HB

Hardness, Rockwell C

33 HRC
24 HRC

Hardness, Vickers

325 HV
262 HV

Same in both: Shear Modulus 77 GPa11.2 Msi · Reduction in Area 40%

Physical

Density and transition temperatures.

Density

7.8 g/cm³0.28 lb/in³
7.75 g/cm³0.28 lb/in³

Melting Point (Solidus)

1,400°C2,552 °F
1,410°C2,570 °F

Liquidus Temperature

1,440°C2,624 °F
1,450°C2,642 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

17.8 W/m·K10.3 BTU/hr·ft·°F
16 W/m·K9.2 BTU/hr·ft·°F

Specific Heat Capacity

420 J/kg·K0.1 BTU/lb·°F
480 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

10.8 µm/m·K6 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Min Service Temperature

-73°C-99 °F
-50°C-58 °F

Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 300°C572 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

7.7×10⁻⁷ Ω·m30.3 µΩ·in
8×10⁻⁷ Ω·m31.5 µΩ·in

Same in both: Electrical Conductivity 2.2 % IACS

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.28 V
-0.15 V

Corrosion Resistance

58 / 100
78 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

42 / 100
30 / 100

Machinability Rating (AISI 1212 = 100 %)

38%
25%

Weldability

65 / 100
55 / 100

Formability (cold)

20 / 100
15 / 100

Castability

68 / 100
65 / 100

Brazeability / Solderability

45 / 100
35 / 100

Polishability

78 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
53 MJ/kg22,786 BTU/lb

Embodied Carbon (primary production)

4.2 kg CO₂/kg
4.6 kg CO₂/kg

Embodied Water

220 L/kg26.4 gal/lb
120 L/kg14.4 gal/lb

Same in both: Typical Recycled Content 70%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

128 kN·m/kg
94 kN·m/kg

Specific Stiffness (E / density)

25.1 MN·m/kg
25.8 MN·m/kg

Modulus of Resilience

1,887 kJ/m³
756 kJ/m³

Thermal Diffusivity

5.4 mm²/s
4.3 mm²/s

Thermal Shock Resistance Index

8
5

Strength versus weight

Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

3005007001,0001,5002,0007.27.47.67.888.2Density (g/cm³)Yield strength (MPa) — log scaleCD4MCuNCB7Cu-2

Manufacturing and finishing

CapabilityCB7Cu-2CD4MCuN
Default condition——
Relative cost$$$ Premium$$$ Premium
Min. machined wall——
Best machined surface——

Both take the same 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.

CB7Cu-2 vs CD4MCuN — frequently asked

Is CB7Cu-2 stronger than CD4MCuN?

Yes. CB7Cu-2 has a typical yield strength of 860 MPa (125 ksi) against 550 MPa (79.8 ksi) for CD4MCuN — about 56% more. Tensile strength is 1,000 MPa (145 ksi) vs 730 MPa (106 ksi).

Which is cheaper, CB7Cu-2 or CD4MCuN?

Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, CB7Cu-2 or CD4MCuN?

CB7Cu-2. Its machinability rates fair (42/100) against poor (30/100) for CD4MCuN; for welding the order is CB7Cu-2 first (good, 65/100) then CD4MCuN (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in CB7Cu-2 and CD4MCuN side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.