W.Nr. 2.4778 with Excellent Thermal Shock Resistance and Wear
A-ONE ALLOY supplies W.Nr. 2.4778 in forms of forgings, round bar,
tube and so on.
UMCo50 is a heat-resistant cobalt alloy with excellent thermal
shock resistance and wear resistance performance. It has great
strength against sulfur-and vanadium-attacks. UmCo-50 has higher
melting point compared to other cobalt based or nickel based
For example, the alloy used for skid rails at a steel mill
undergoes regular use at 1350°C.
Other alloys could not be used due to their low melting point in
the application related to heat treatments and furnaces. But W.Nr.
2.4778 shows successful results.
An example of Chemical composition XUNSHI supplied to customer
Since thermal shock resistance was given first priority when
developing W.Nr. 2.4778, this alloy shows far more outstanding
thermal shock resistance than the popularly used 25Cr-20Ni
stainless steel. For example, even after repeating the heating and
cooling cycle (1000-water cooling-7 seconds) for 500 times, no
cracking occurred. As a practical example, the alloy was used for
four and a half years as a tray which was heated up to 1000 in a
heavy oil furnace to quench various quenching agents. Hardly any
cracking occurred in W.Nr. 2.4778, whereas the 25Cr-12Ni alloys
were able to be used for only 8 months in average.
As for the wear resistance of W.Nr. 2.4778, hardly any
deterioration was found after being used as a sintering bar for
copper sulfide for 50 months. On the other hand, cast iron parts
used till then were heavily corroded, oxidized and worn even though
operations were conducted at 900, making them usable for only three
and a half months.
W.Nr. 2.4778 can be welded together by arc or oxy-acetylene
methods. When higher wear resistance is required, weld additionally
with BISHILITE (HARDFACING ALLOYS). When welding W.Nr. 2.4778 to
stainless steel or steel, MA-W welding rod can be used.
XUNSHI has strong strength in production of cobalt alloy. Available
grades include Haynes 25(L605), Haynes 188, MP35N, MP159, Waspaloy,