Thermal expansion coefficients steel weld metal

Zirconium weld metal may corrode preferentially when H2SO4 concentration is approximately 55% and higher. Heat treatment at 775 + 15°C for 1 h per 25.4 mm of thickness can be applied to restore the corrosion resistance approaching that of the parent metal. However, this high-temperature heat treatment is not suitable for equipment made of zirconium/steel-clad materials because of the large difference in thermal expansion coefficients between these two alloys. Heat treatment at a much lower temperature, such as 510 + 20°C, should be applied when there is... 

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