The influence of the constraint effect on the mechanical properties and weldability of the mismatched weld joints. Part II
Currently the welding as a technological process is concerned with special processes, the results of which cannot be checked in a complete degree by subsequent control, test of production what finally causes uncertainty of work of welded constructions. The process of welding is related to the local change of the internal energy of welded system and that leads to the local change of state of material expressing by change of microstructure and mechanical properties. This phenomena decide on the assessment of susceptibility of materials under defined welding condition and estimate of the weldability. It is compound relation and the mechanical behaviour of welded joints is sensitive to the close coupling between modules: heat transfer, microstructure evolution an mechanical fields. Welding process in physical meaning it is jointed with three laws govern mass and heat flow the laws of conservation of: mass, momentum and energy. The knowledge of the run of thermo-dynamical process under welding indicates on the possibility of active modelling and control of welding process with use intensive and extensive parameters. As the weld metal cools in the temperature range 2300 to 1800°K, the dissolved oxygen and deoxidising elements in liquid steel react to form complex oxide inclusions of 0.1 to 1 μm size range. In the temperature range 1800 to 1600°K, solidification of liquid to δ ferrite starts und envelops these oxide inclusions. After δ ferrite transforms to austenite in the temperature range 1100 to 500°K, the austenite transforms to different ferrite morphologies such as ferrite: allotriomorphic, Widmanstättena, and acicular. The macro-mechanical heterogeneity of welded structures is one of their primary features. The heterogeneous nature of the weld joints is characterised by macroscopic dissimilarity in mechanical properties. Numerical weldability analysis is a new powerful research and development tool which is useful for metallurgistics technologist and design engineers. Saying strictly the numerical analysis of weldability comprises thermodynamic, thermomechanical and microstructural modelling of the welding process. The result of this analysis is material susceptibility (SU). The fracture resistance of welded joints is mainly characterised by normalised parameters: SU1 = KIth / KIC for cold cracking or in the exploitation condition by SU2 = δ/δC or J/JC, SU1 ≠ SU2. From above-mentioned equations result that does not exist one global parameter which defines the step of susceptibility SU of base materials has been also executed with use of SINTAP program
- 1. MAN B&W Diesel A/S.:Waste Heat Recovery Systems. Copenhagen Denmark, 2007.
- 2. MAN B&W Diesel A/S.:Soot Deposits and Fires in Exhaust Gas Boilers. Copenhagen Denmark, 2004.
- 3. MAN B&W Diesel A/S.: Waste Heat Recovery System-Green Ship Technology Seminar. p.1-13, Hainan,China, 2010.
- 4. MAN B&W Diesel A/S.:Thermo Efficiency System for Reduction of Fuel Consumption and CO2 Emission. Copenhagen Denmark, 2007.
- 5. WARTSILA Diesel A/S.:Energy savings and environmental benefits via Exhaust Gas Heat Recovery.
- 6. C.J. Butcher, B.V. Reddy.: The second thermodynamic law analysis of a waste heat recovery based power generation system. International Journal of Heat and Mass Transfer,Vol.50, No.11-12, p.2355-2363, 2007.
- 7. Dai Y., Wang J., Gao L..: Parametric Optimization and Comparative Study of Organic Rankine Cycle (ORC) for Low Grade Waste Heat Recovery.Energy Conversion and Management, Vol.50, p.576-582, 2009.
- 8. Yalcin DURMUSOGLU, Tanzer SATIR, Cengiz DENIZ, Alper KILIC.:A Novel Energy Saving and Power Production System Performance Analysis in Marine Power Plant Using Waste Heat. 2009 International Conference on Marine Learning and Applications, p.751-754, 2009.
- 9. World ShippingCouncil. http://www.worldshipping.org/benefits-of-liner-shipping, 25, January 2010.
- 10. Review of Marine Transport 2008. United Nations Conference on Trade and Development , ISBN 978-92-1-112758-4, United Nations, 2008.
- 11. N.R KRISTIANSEN, H.K. NIELSEN.:Potential for Usage of Thermoelectric Generators on ships.Journal of ELECTRONIC MATERIALS, Vol.39, No.9, p.1746-1749, 2010.
- 12. J.Yang, F.R.Stabler.:J. Electron.Mater.38, 1344(2009).
- 13. Liu Shi-Jie, Chen Wu,Cai Zhen-Xiong, Zheng Chao-Yu.: Study on the application of high temperature heat pump to recover waste heat of marine diesel engine. 2009 International Conference on Energy and Environment Technology, Vol. 1, p. 361-364, 2009.
- 14. MAN B&W Diesel A/S.: TCS-PTG Savings with Extra Power. Copenhagen Denmark.
- 15. P.K. Nag, S. De.: Design and operation of a heat recovery system generator with minimum irreversibility.Appl. Therm. Eng.,Vol.17, p.385-391, 1997.
- 16. China State Shipbuilding Corporation.:Capacities of Auxiliary Machinery and Engine Performance Data for 9K98ME-C7 designed for WHR. China, 2010.