Dunno about the Ti, Zr suffix you have, but in the Key to Steel CD (1999) this is what it says for material code 1.4852 Heat resisting steel GX40NiCrSiNb35-25
Composition: (min/max)
C 0.35 0.24
Si 1.00 2.50
Mn 0 1.50
P 0 0.035
S 0 0.030
Cr 24.0 26.0
Ni 33.0 35.0
Nb 0.80 1.80
Heat treatment condition
State of delivery - Cast
Properties at ambient temperature
0.2% yield stress >=220 N/mm2
Tensile strength >=400 N/mm2
Elongation (Lo =5do) up to 25 mm wall thickness 5%
At elevated temperatures
1% 10 000 hr creep limit
700 C >=72 N/mm2
800 C >=41 N/mm2
900 C >=22 N/mm2
1000C >= 9 N/mm2
1100 C >= 2 N/mm2
Shrinkage - 2.5%
Working temperature <=1100 C
Physical props:
Thermal expansion between 20 and 400 C
10(-6)K(-1)
400 15.5
800 17.0
1000 18.0
Density (20C) 8.0 kg/dm3
Spec heat (20C) 8.0 J/g.K
Heat conductivity 14.6 W/(K.m)
Structure Austenite carbide
Welding Yes