DAIKOFCW 1021

FCAW
  • COBALT ALLOYS
Gr. 21

Description

Cobalt based cored wire for hardfacing
Grade 21 flux cored wire provides a low austenitic type deposit with excellent work hardenable, high temperature, strength, and impact resistance. It is a good choice for valve trim and steam and fluid control valve bodies and seals. It bonds well to all weldable steels, including stainless steel. Excellent for corrosion resistance and metal-to-metal wear resistance. Used for integral seats and guides of large water and high-pressure valve bodies, hot shears, forging dies, pump shafts and sleeves, hot punches etc.
Specifications
EN ISO 14700
TCo1
AWS A5.21
ERCCoCr-E
DIN 8555
MF 20-MF-350-CKTZ
Shielding
I1, I3
Positions
PA, PB, PC
Current
DC+
Packaging Type
BS300 spool
Asme qualifications
F-No (QW432)
72
A-No (QW442)
-

Hardness

31-33 HRC as welded - 38-41 HRC work-hardened
Chem. Comp. %
0
C
0.25
Mn
1
Ni
2.5
Cr
28.5
Si
1
Fe
4
Welding Parameters
1.2 mm
1.6 mm
Ampere
100A - 250A
140A - 350A
Voltage
16V - 29V
26V - 30V
Packaging
Ø 1,2÷1,6mm
Ø 1,2÷1,6mm
Packaging Type
BS300 spool
BS300 spool
Anti-wear Characteristics
Adhesive wear
Abrasive wear
Impact
Corrosion
Heat
Description

Application

The Gr. 21 subfamily, cobalt-based with a low carbon content, offers an excellent combination of high-temperature resistance and high ductility. These characteristics provide greater resistance to cracking during welding compared to high carbon content types. The material possesses excellent resistance to corrosion, oxidation, and sulfurization, along with good resistance to cavitation erosion. It's particularly effective against thermal shocks, outperforming high carbon types in such contexts. Although its resistance to adhesive wear is lower than that of high carbon types, its shock-absorbing properties are significantly superior. Gr. 21 is widely used for overlaying on valve fittings and valve seats, hot cutting blades, punches and dies, ingot gripper ends, and hot steel handling equipment. Gate valves in catalytic crackers of the petrochemical industry represent a prime application. It is also employed across various sectors, including steel mills, cement plants, marine industry, and power generation. Although preheating is not strictly necessary, it is advisable for the first layer on hardenable alloy steels. Interpass control up to 200 °C is suggested to minimize the risk of hot cracking in multi-pass deposits. The deposits can be machined with carbide tools and can be finished by grinding if necessary.

Alloy Type

CoCrMo alloy matrix containing dispersed hard carbides.

Microstructure

In the as-welded condition the microstructure consists of a cobalt based austenite with a number of carbides and other complex phases.

Materials

Used for surfacing mild, low alloy and stainless steels and also for nickel base alloys. Can also be used for the repair of similar base materials (UNS R30021, Stellite 21 - Deloro Stellite) although it is optimized for surfacing not joining.

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