Lastek 256 A

Valves and valve seats

Cobalt based TIG- and oxy acetylene welding rod for hardfacing where maximum resistance to wear and corrosion at red heat temperature (up to 900-1.000 °C (1.650-1.830 °F)) is required.

Deposit machinable only with hard metal tools.

Excellent resistance to impact and thermal shocks and good resistance to acetic and nitric acid, organical chemical products such as: petroleum, plastic, rubber and resins, even liquid metals such as aluminium and zinc.

Also suitable for the food and pharmaceutical industry.

Specifications & Usage


Warm cutting tools, metal shear blades, stone breakers, hammers, valves and valve seats of combustion motors, glass cutting tools, shafts and pump bearings.

Hardness: 38-46 HRC.

Hot hardness: approx. 31 HRC @ 600 °C.


Remove all rust and dirt. Sharp edges should be rounded.

Heat the base metal until it ’sweats’ (no melting).

Use a carburising flame, length of the feather approx. 2.5 to 3 times the length of the inner cone.

The surfacing can be lightly re-melted for optimum homogeneity.

Avoid too much dilution by using an as low as possible welding current.

For TIG welding, apply at least 2 layers in order to obtain the desired characteristics. (To avoid too much dilution with the base metal.)

On difficult to weld metals a base layer with Lastek 982 is recommended.


Welding proces: Tig welding (GTAW)
Material Type: Hard facing
Welding positions: NA
Norm : DIN 8555T1
Classification: G 20-40
Norm: AWS A5.21
Classification: ER CoCr-A
Minimum packing: 5 kg in a plastic box