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Home Material Sciences 30% Improvement Of Ultrasonic Impact Treatment Of Welded Joints

30% Improvement Of Ultrasonic Impact Treatment Of Welded Joints

Description

The surface state plays an important role during exploitation of constructions and especially such ones, which work in the vibration conditions. Such terms lead to formation of cracks in surface layers, which result in fatigue destruction of construction as a whole during future operation. The different welded joints are the most dangerous sites of constructions. There are a plenty of methods for the surface hardening of metals, which can improve the fatigue life and durability of responsible elements and parts of different machines, mechanisms and constructions. Employment of such methods allows considerably increasing the operation life of machines and constructions. A number of them are based on the severe plastic deformation of surface due to multiple impact loads. The deformation leads to hardening of surface and formation of compressive residual stresses in surface layers. Among the traditional technologies in this direction the following methods are widely used: hammer peening, shot peening, etc. Recently, the Ultrasonic Impact Treatment (UIT) or Ultrasonic Peening (UP) becomes more widely used as a method for local hardening of the metal surfaces. Especially successful experience of application of the UP is related to hardening of welded joints.

Innovative Aspect and Main Advantages

New modification of portable ultrasonic apparatus for hardening and relaxation treatment of welded joints with the output power of 300 W is developed at the G.V.Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine. The developed ultrasonic equipment is supplied with piezoceramic transducer and has low dimensions and weight. The technological recommendations for application of this method in industry are developed at the Ye.O. Paton Welding Institute of the N.A.S. of Ukraine. Application of piezoceramic transducers instead of magnetostrictive ones as the ultrasound source is the key difference of our development in comparison with the one, which is proposed by Applied Ultrasonic Inc. (USA). The latter is much heavier (by 3-4 times), both considerable energy consumption and water-cooling are needed. Therefore, it is difficult to use the equipment in the field conditions. Application of piezoceramic transducers substantially reduces the energy consumption, cost of equipment, and also extends technological possibilities due to simplicity of the use in different branches of industry. The use of this method allows improving fatigue strength of welded joints by 20 – 30 % and permits substantially increasing their durability.

Areas of Application

Application of technology of UP treatment prolongs the operation life of responsible constructions in a bridge- and ship-building, on a transport, in production of Goliath cranes and in other branches of industry.


Fig. 1 The results of fatigue tests of welded seem:
1 – after welding; 2 – after welding and UIT in mode 1;
3 – after treatment in mode 2.


Fig. 2 The portable ultrasonic apparatus for hardening and
relaxation treatment of the welded joints with
the power output of 300 W.

Stage of Development

UIT technology and equipment are protected by:

  • Patent of USA # 6467321. Published 23.10.2002.
  • Prototype available for testing.
  • Tested, available for demonstration – field tested.

Contact Details

Contact person: Dr Sci. Prokopenko Georgiy
G.V.Kurdyumov Institute for Metal Physics, N.A.S. of Ukraine
Address: 36 Vernadsky Blvd., 03142 Kyiv, Ukraine
Tel/Fax: +(380)44 424-0521
Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

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