Cobalt #21 CTD Electrode
Class: ECoCr-E
AWS: A5.13
DURAMAX COBALT #21 CTD ELECTRODE
Conforms to Certification: AWS A5.13 | ASME SFA 5.13
Weld Process: Shielded Metal Arc
| AWS Chemical Composition Requirements | ||
| C = 0.15 – 0.40 | Mn = 1.5 max | Si = 2.0 max |
| Cr = 24 – 29 | Ni = 2.0 – 4.0 | Mo = 4.5 – 6.5 |
| Fe = 5.0 max | W = 0.50 max | Co = Remainder |
| Other = 1.0 max | ||
Product Description:
DURAMAX Cobalt #21 SMAW coated electrodes deposit a low austenitic cobalt type alloy with excellent work hardenable high temperature, strength, and impart resistance. It has excellent metal-to-metal wear resistance and bonds well to all weldable steels, including stainless. These electrodes have very good strength and ductility in temperatures up to 1600°F (871°C). The deposits are resistant to thermal shock, oxidizing, and reducing atmospheres. Early applications of these types of alloys were found in jet engine components such as turbine blades and vanes. The deposit is a solid solution straightened alloy with a relatively low weight-percent carbide phase in the microstructure. Hence, the alloy is very tough and will work harden. Deposits possess excellent self-mated galling resistance and also are very resistant to cavitation erosion. electrodes are used where the resistance to thermal shock is important.
| Typical Applications: |
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| – Guide Rolls | – Hot Extrusion Dies | – Forging Dies | |
| – Hot Shear Blades | – Cavation Repair | – Valve Trim | |
| – Chemical Valves | – Petrochemical Valves | – Tong Bits | |
| Deposited Chemical Compositon % (Typical) | |||
| C = 0.23 | Mn = 0.8 | Si = 0.8 | |
| Cr = 27.7 | Ni = 2.8 | Mo = 5.4 | |
| Fe = 2.4 | W = 0.05 | Co = Balance | |
| Typical Deposit Characteristics: |
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| – Abrasion Resistance | Fair | – Hardness | HRC 24 – 28 |
| – Impact Resistance | Excellent | – Work Hardened | HRC 40 – 45 |
| – Corrosion Resistance | Good | – Hot Weld Hardness | Excellent |
| – Deposit layers | 3 Layers Max | – Metal-to-Metal Wear | Excellent |
| – Machineability | Use Carbide tools | – Surface Cross Check | No |
Recommended Operation of Welding Rods
Flat Welding
| Diameter | Amps DCEP |
| 1/8 | 90 – 120 |
| 5/32 | 145 – 165 |
| 3/16 | 175 – 195 |