**Author details**

Michal Pohanka and Petr Kotrbáček *Brno University of Technology, Heat transfer and Fluid Flow Laboratory, Brno, Czech Republic* 

## **6. References**

	- [12] Burggraf, O. R. An exact solution of the inverse problem in heat conduction theory and applications. *Int. J. Heat Transfer*, 1964, Vol. 86C, pp. 373-382.

**Chapter 2** 

© 2012 Golański, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Golański, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Cylinder and valve chamber castings of large power steam turbines are usually made of low alloy Cr - Mo - V and Cr - Mo cast steels. Forming of the microstructure and mechanical properties of cast steels takes place through heat treatment, thus far mostly consisting of normalizing and tempering. As a result of such a treatment the cast steels of diverse wall thickness reveal microstructures from ferritic – pearlitic to bainitic – ferritic with various

Operation of the cast steels under creep conditions contributes to the occurrence of deformations, fractures and changes in the microstructure, decreasing their functional properties. The resistance to crack expressed by impact energy falls drastically. The value of impact energy of test pieces taken from cast steels after long-term service was considerably

below the required level of 27J, frequently reaching the value of 6 - 10J (Fig. 1).

**Figure 1.** Impact energy of turbine cylinder cast steel in the post-operating condition

**Regenerative Heat Treatment** 

**of Low Alloy Cast Steel** 

Additional information is available at the end of the chapter

Grzegorz Golański

**1. Introduction** 

http://dx.doi.org/10.5772/50505

ferrite, pearlite and bainite amount.


**Chapter 2** 
